Estates and Facilities
THE UNIVERSITY OF READING
CONTROL OF LEGIONELLA
BACTERIA WITHIN WATER
SYSTEMS
POLICY
Page 1 of 103 February 2016 review – Legionella Control – University of Reading
This Document sets out the University of Reading Policy and Procedures for managing and dealing with Legionella in water systems.
Approved by Facilities Management Committee and the Health and Safety Committee.
LEGIONELLA MANAGEMENT POLICY
Statement of Intent
To define how the Duty Holder manages the potential risk from legionella contamination
in accordance with current legislation and good practice.
The University of Reading Legionella Policy conforms to the Health and Safety at Work Act
1974 etc.; The Control of Substances Hazardous to Health (COSHH) Regulations 2002 (as
amended); the H.S.E Approved Code of Practice L8, 4th edition, 2013: Legionnaires’
disease “The Control of Legionella Bacteria in Water Systems” (ACOP L8) and the
guidance documents HSG274.
This Policy and Procedures will apply to all buildings and all individuals employed and/or
engaged by the University without exception.
The University of Reading Policy on Legionella:
To comply with its legal duties, the University will:
•
•
•
•
•
•
•
Identify and assess sources of risk.
Prepare a scheme for preventing or controlling the risk.
Ensure suitable and sufficient resources are available.
Implement, manage and monitor all precautionary control measures
identified.
Keep records of all such measures.
Nominate employees and others with responsibility for implementing this
policy.
Review this Policy at least every 2 years.
Signed :
………………………..…………..
Date
……………………………………
Duty Holder Title
……………………………………
Name:
……………………………………
Page 2 of 103 February 2016 review – Legionella Control – University of Reading
Estates and Facilities
THE UNIVERSITY OF READING
CONTROL OF LEGIONELLA
BACTERIA WITHIN WATER
SYSTEMS
PROCEDURES
Page 3 of 103 February 2016 review – Legionella Control – University of Reading
INDEX
Section
Description
Page No
1
Legionella background
7
2
Responsibilities and Duties
8
3
Procedures for risk assessment (Classification)
11
4
Areas of Risk Control
12
4.1 Cooling Towers/AC equipment
4.2 Showers and Spray taps
4.3 Hot Water System/s
4.4 Tank/s and Tank fed Cold water system
4.5 Infrequently used outlets
4.6 Drinking water distribution
4.7 Water Filters
4.8 Water Heaters
4.9 Vending Machines
4.10 Water Softeners
4.11 Fogging and Misting systems
4.12 Materials in Contact with water
4.13 Legionella Sampling
4.14 Fume cupboards with scrubber units
4.15 Thermostatic Mixing Valves
4.16 Sampling of Boosted/tank water for drinking
4.17 Expansion Vessels
4.18 Dental Equipment
12
13
14
15
16
17
17
18
18
19
19
19
20
20
20
20
21
23
5
Management Procedure
24
6
Specific Non-compliance procedure
25
7
Procedure for projects
26
8
Training
26
Page 4 of 103 February 2016 review – Legionella Control – University of Reading
Appendix No
Appendix 1
Appendix 2
Appendix 3
Appendix 4
Appendix 5
Appendix 6
Appendix 7
Appendix 8
Appendix 9
Appendix 10
Appendix 11
Description
Page No
Flow Chart
Procedure
Procedure
Procedure
Procedure
Procedure (MSPT1)
Procedure (MSPT1a)
Procedure (MSPT 2)
Relevant Legislation Guidance & Standards
Key Contact Details
Requirements Cold Water Tanks
Responsibility
Risk Assessment
Temperature Monitoring
Pasteurisation of hot water system
Flushing infrequently used outlets
Complete Chlorination. (Hot & Cold)
Complete Disinfection using Peroxide
Full Risk Assessment and Schematic
27
29
30
31
32
34
35
36
38
40
41
Appendix 12
Appendix 13
Appendix 14
Appendix 15
Appendix 16
Appendix 17
Procedure (MSPT3)
Procedure (MSPT4a)
Procedure (MSPT4b)
Procedure (MSPT4c)
Procedure (MSPT5)
Procedure (MSPT6)
Calorifier/Buffer vessel De-scale
Tank Inspection Domestic
Tank Inspection <1000ltrs
Tank Inspection >1000ltrs
Tank Inspection and Sampling
TMV Failsafe
43
47
48
49
50
51
Appendix 18
Appendix 19
Appendix 20
Appendix 21
Appendix 22
Appendix 23
Appendix 24
Appendix 25
Appendix 26
Appendix 27
Appendix 28
Appendix 29
Appendix 30
Appendix 31
Appendix 31A
Appendix 32
Appendix 33
Procedure (MSPT7)
Procedure (MSPT 8)
Procedure (MSPT 9)
Procedure (MSPT10a)
Procedure (MSPT10b)
Procedure (MSPT11)
Procedure (MSPT 12)
Procedure (MSPT13)
Procedure (MSPT14)
Procedure (MSPT18)
Procedure (MSPT 19)
Procedure (MSPT20)
Procedure (MSPT21)
Procedure (MSPT22)
Procedure (MSPT23)
Procedure (MSRT1)
Procedure (MSRT1a)
Showerhead cleaning
Flushing unused outlets
Water filter change
Stored Water Heaters
Instantaneous Water Heaters
Legionella Training
Water Softener Disinfection
Fogging and Misting System Disinfection
Fogging and Misting systems
Emergency eyewash and emergency showers
Legionella Sampling
Bacterial Sampling
Monitoring Temperatures from Taps
Calorifier Temp monitoring (Flow/Return)
Expansion Vessel Inspection
Complete Chlorination. (Hot & Cold)
Complete Disinfection using Peroxide
52
53
54
55
56
57
58
59
60
61
62
63
64
66
67
68
70
Appendix 34
Appendix 35
Procedure (MSRT2)
Procedure (MSRT3)
Full Risk Assessment and Schematic
Calorifier/Buffer vessel De-scale
72
74
Appendix 36
Appendix 37
Procedure (MSRT4)
Procedure (MSRT4a)
Replace CWST
Chlorination of CWST
78
80
Appendix 38
Procedure (MSRT4b)
Chlorination using Fogging equipment
82
Appendix 39
Procedure (MSRT5)
TMV service and fail safe
83
Appendix 40
Appendix 41
Appendix 42
Procedure (MSRT6)
Procedure (MSRT7)
Procedure (MSRT8)
Descaling taps
Water Filter Change
Legionella Re-sampling
85
86
87
Page 5 of 103 February 2016 review – Legionella Control – University of Reading
Appendix No
Description
Appendix 43
Appendix 44
Appendix 45
Appendix 46
Maintenance Periods
Maintenance Different Property Type
Non-Compliance Procedure
Legionella – Action Level Guidance
88
90
91
92
Appendix 47
Appendix 48
Appendix 49
Safety Note 43
Water Softener Disinfection
Safe Occupation of new/refurbished buildings
and safe shut down of water systems
93
99
100
Procedure (MSRT9)
Page 6 of 103 February 2016 review – Legionella Control – University of Reading
Page No
PROCEDURES FOR LEGIONELLA MANAGEMENT
1.0 LEGIONELLA BACKGROUND
Legionnaires’ disease is a potentially fatal form of pneumonia which can affect anybody,
but which principally affects those who are susceptible because of age, illness,
immunosuppression, smoking etc. It is caused by the bacterium Legionella pneumophila,
and related bacteria. Legionella bacteria can also cause less serious illnesses, which are
not fatal or permanently debilitating. The collective term used to cover the group of
diseases caused by Legionella bacteria is Legionellosis.
Legionnaires’ disease is normally contracted by an individual inhaling Legionella bacteria
either in tiny droplets of water or in droplet nuclei (particles left after the water has
evaporated).
The incubation period is 2-10 days (usually 3-6 days).
General
It is possible that occupants of the University of Reading may be exposed to Legionella
bacteria, which may be present in the water system.
The presence of Legionella bacteria in water does not itself constitute a danger. However,
the mode of contracting the disease is by inhalation of water in an aerosol. An aerosol
may be caused by spraying, showering, running taps etc.
Factors to be considered in the risk assessments
•
•
•
•
•
contamination
amplification
transmission
exposure
host susceptibility
Potential areas of contamination
Risk assessments have identified a number of groups that are potentially at risk;
• Staff
• Students
• Visitors
• General public
Page 7 of 103 February 2016 review – Legionella Control – University of Reading
Areas of risk, where control is necessary
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
4.1 Cooling towers/Air Conditioning (AC) equipment
4.2 Showers and spray taps
4.3 Domestic hot water system
4.4 Tank/s and tank fed cold water systems
4.5 Infrequently used outlets
4.6 Drinking water distribution
4.7 Water filters
4.8 Water heaters
4.9 Vending machines requiring a supply of mains water
4.10 Water softeners
4.11 Fogging and misting systems
4.12 Materials in contact with water
4.13 Borehole supply
4.14 Legionella sampling
4.15 Fume Cupboards with Scrubber Units
4.16 Thermostatic Mixing Valves (TMV)
4.17 Sampling of Boosted/tanked water for drinking purposes.
4.18 Expansion Vessels
4.19 Dental Equipment
2.0 RESPONSIBILITIES AND DUTIES
General
The University of Reading has responsibility for compliance with The Health and Safety at
Work etc. Act. (1974) and all associated legislation. This includes specific legislation
relating to Legionella, as set out in Appendix 1. This document should be read in
conjunction with University of Reading Health and Safety Policy.
The management of Legionella in water is now controlled by a variety of different
legislation (see Appendix 1). Responsibility for ensuring compliance with this legislation
within the University of Reading for fixed water systems has been delegated to the Estates
and Facilities (E&F). Schools/Directorates are responsible for any non-fixed equipment
that they own. “Safety Note 43 – Control of Legionella in Departmental Equipment”
provides guidance on this aspect of Legionella control. Appendix 47
Responsibility for the implementation of the Control of Legionella bacteria within water
systems (Policy and Procedures), along with the management of Legionella rests with the
Duty Holder. The Duty Holder will appoint other ‘duty holders’ who will be responsible
for management of the control of Legionella.
The Duty Holder will ensure that all appropriate personnel are familiar with the contents
of the Control of Legionella bacteria within water systems (Policy and Procedures), insofar
as it is relevant to their roles and responsibilities.
Page 8 of 103 February 2016 review – Legionella Control – University of Reading
Legionella Duty Holder & Responsible Person
Ensure compliance with L8 policy.
Ensure the monitoring regime is adhered to.
Ensure the Inspection regime is adhered to.
Order works from providers as necessary.
Update records as appropriate.
Maintain Web based data (Electronic & Web Portal).
Ensure compliance with policy and specification.
Facilitate any monitoring or inspection work.
Facilitate and ensure completion of any remedial work identified.
Ensure all necessary documentation is completed.
Responsible for the day to day operation of Legionella management programme.
Water Quality Consultant (Deputy Responsible Person)
Advise on all university water quality matters in order with the ACOP L8 document.
Audit performance of MTC contract (Using audit check list to review Risk Assessment,
Schematic, Chlorination and other activities by MTC contactor, reporting to Duty Holder).
Ensure compliance with policy and specification.
Provide cover for Duty Holder when not available.
Specialist Water Treatment MTC
Ensure compliance with L8 policy.
Carry out Risk Assessments, Chlorination & Schematics.
Carry out tests, as required, on water systems.
Carry out investigations and remedial works as instructed.
Carry out all weekly/monthly inspection/monitoring/maintenance tasks as instructed.
Ensure all necessary documentation is completed
Provide documentation in electronic format as directed by Duty Holder.
Head of Projects & Design
Ensure systems are designed to ensure compliance with the L8 document.
Ensure systems are installed to ensure compliance with the L8 document.
Ensure compliance with policy and specification.
Direct Labour Manager
Ensure compliance with L8 policy.
Facilitate any monitoring or inspection work.
Ensure appropriately trained personnel available for L8 compliance works.
Page 9 of 103 February 2016 review – Legionella Control – University of Reading
Heads of Department:
Ensure compliance with L8 policy.
Ensure departmental equipment is maintained in house or by contractors to standard
necessary for control of Legionella.
Keep records of departmental equipment servicing and maintenance.
Facilitate any monitoring or inspection work.
Ensure that NO modifications/alterations or additions to water systems are carried out,
unless written approval is obtained from Legionella Duty Holder.
University Health & Safety Committee
Review Policy every 2 years.
Head of Health & Safety Services
Ensure compliance with L8 policy.
Where required, investigate and report to the University Health and Safety Committee on
any alleged incident of accidental Legionella exposure, and also for ensuring correct
reporting of incidents under RIDDOR, where appropriate. To notify the Occupational
Health Service should any member of staff be involved in an incident of accidental
Legionella exposure in order that medical advice can be given. Ensure that any accidental
exposure is recorded in the employee’s medical notes.
Project Managers / Consultants
Ensure compliance with L8 policy.
Employ current MTC Water Contractor to carry out Risk Assessment, schematic and
chlorination prior to handover.
see Appendices 2 and 4
Page 10 of 103 February 2016 review – Legionella Control – University of Reading
3.0 PROCEDURES FOR RISK ASSESSMENT
Classification
University of Reading buildings and equipment may fall into one of four categories, which
are:
Class A -
High Risk
Cooling towers associated with air conditioning systems. Currently
there are no cooling tower installations within the University.
Class B -
Medium Risk
Large residential or academic premises, with cold water system fed
via stored water and hot water supplied via calorifier/s with a
pumped distribution or mains water system. Generally on these
systems 2 yearly risk assessments, chlorination and schematic will be
conducted but also additionally weekly flushing (where identified),
monthly temperature monitoring, 3 monthly shower cleaning, 6
monthly tank inspections, annual calorifier cleaning and other works
recommended in their individual risk assessment.
Class C -
Low risk
Small residential and domestic premises, including large complexes
with self-contained living units. Typically the water systems are of
the "domestic" type, with high turnover, i.e. with a cold water
gravity-feed tank to a conventional copper storage cylinder.
Generally on these systems 2 yearly risk
assessments/chlorination/schematic will be conducted. Any
additional work required will be presented to the Fund Holder for
completion. It is not envisaged that monthly temperature testing, 3
monthly shower cleaning, 6 monthly tank inspection etc.. will be
carried out as access to these sites is occupier driven.
Class D -
Very Low risk
Small residential and domestic premises, including large complexes
with self-contained living units. Typically the water systems are of
the "domestic" type, with high turnover, i.e. mains water system with
a combination boiler, having no tank or cylinder. Generally these
systems can be desk risk assessed but a small percentage may be
fully risk assessed every 2 years.
Page 11 of 103 February 2016 review – Legionella Control – University of Reading
Risk Assessment
The University of Reading shall conduct risk assessments with schematics with respect to
Legionella bacteria. These will be updated every two years or more frequently as
determined by the risk assessment on:
•
•
•
•
Existing buildings.
New buildings.
Building where major refurbishment has been undertaken.
Change of use of a building.
The University of Reading will employ qualified and competent persons to carry out the
risk assessment on its behalf. The risk assessments are held centrally by Estates and
Facilities (E&F).
The Responsible Person will instigate a review as required or on a 2 yearly cycle.
A risk assessment of fixed water systems will be conducted culminating in a risk
assessment report with a schematic drawing and electronic logbook for each system.
see Appendices 11 & 5 ~ for risk assessment procedure and example (MSPT2) and flow
diagram
4.0 AREAS OF RISK AND CONTROL
4.1
Cooling Towers associated with Air Conditioning Equipment
There are currently NO COOLING TOWERS in the University of Reading. Cooling
towers may only be installed under exceptional circumstances which prevent the
use of an alternative plant. Dispensation for their use can only be granted by the
Responsible Person.
Page 12 of 103 February 2016 review – Legionella Control – University of Reading
4.2
Showers and Spray Taps
Risk
A high level of spray and therefore aerosol will result with shower and spray tap
operation. The risk of Legionellosis is higher, as infection can only occur if infected
aerosols are inhaled. Risk can be reduced by cleaning and disinfecting shower or spray
head/s.
Control:
Clean, descale and disinfect shower and spray tap heads 3 monthly.
see Appendix 18– Procedure for Shower Head Cleaning (MSPT 7)
Each showerhead to be cleaned and descaled by one of:
1.
Water Quality – Measured Term Contractor (WQ-MTC)
2.
E&F, DLO (Direct Labour Operative)
Recorded information must be returned to E&F for on-going management.
Emergency / showers, eye wash and spray taps
Should be subject to a 3 monthly flushing and disinfection maintenance regime. To be
conducted by:
1
Water Quality – Measured Term Contractor (WQ-MTC)
2
E&F, DLO (Direct Labour Operative)
see Appendix 27 – Procedure (MSPT 18)
It is the policy of University of Reading to remove any existing spray emission type taps
and prohibit the installation of any new units. Taps that produce spray emission as a result
of lime scale should be notified by WQ-MTC to E&F for replacement.
Page 13 of 103 February 2016 review – Legionella Control – University of Reading
4.3
Hot Water System/s
Risk
The ideal growth temperature range for Legionella bacteria is 20-45°C. Temperatures
between 20-45°C are not unusual in poorly managed or poorly specified water systems.
The combination of the above temperature range with the presence of scale, debris and
stagnation within a hot water system will result in Legionella growth.
Control
The University of Reading adopts a temperature regime for the control of Legionella in
domestic hot water systems by maintaining stored water at 60ºC, with a minimum return
temperature of 50°C. Experimental data has shown at 50°C Legionella bacteria die within
2 hours, at 60°C death should occur within 2 minutes and at 70°C (pasteurisation
temperature) instant death occurs.
Water should leave the calorifier/s at 60°C and should return at min 50°C.
Monthly, temperatures are recorded from sentinel taps (additional sentinels will be
selected in complex buildings) and flow/return on calorifiers (see Appendices 30 & 31)
(MSPT21 & MSPT22) by the WQ-MTC Contractor. All data to be provided electronically
to E&F for further management.
Large or Commercial Systems
In large or commercial systems, due to high storage levels, stratification may occur in
calorifiers. Therefore where possible a shunt pump should be fitted and set to operate via
a time switch, which will heat the entire contents of the calorifier to 60ºC for one hour
per day. During low use period (01:00 – 06:00)
Where practicable, each system should be fitted with a circulation pump on the return
leg.
Where practicable, each system should have sensors attached to the Building
Management Systems (BMS) fitted to the flow and return legs. A daily log will be taken to
confirm the correct operating temperatures.
Non-compliances must be reported immediately to the Legionella Duty Holder.
Each calorifier must be subject to an annual maintenance inspection. The calorifier is
isolated from the building circuit, the shell is drained down, internal surfaces are
inspected and cleaned (see Appendix 12 ( MSPT 3 ). Steam heated calorifier/s are
descaled by E&F.
Immediately prior to a calorifier being returned to service a full pasteurisation process
(see Appendix 7) must be carried out. All data to be provided electronically to E&F for
further management.
Page 14 of 103 February 2016 review – Legionella Control – University of Reading
Small Water Systems
These are typically domestic residential premises. For such systems, the entire hot water
system must be subject to disinfection using chlorine every 2 years.
The procedure is shown in (Appendix 9 MSPT1).
4.4
Tank/s and Tank Fed Cold Water Systems
Risk
The ideal growth temperature range for Legionella bacteria is 20-45°C. Cold water
temperatures of 20-25°C can be found in some domestic systems. Presence of debris,
stagnation and non-approved materials will contribute to legionella growth. The aim is to
maintain the water condition as is found in mains water. The maintenance regime is
designed to keep temperatures below 20°C, and to keep debris and stagnation at a low
level.
Control
The University of Reading adopts a temperature regime for the control of Legionella at the
majority of the sites. Water temperature must not exceed 20°C.
Monthly temperatures are to be recorded from sentinel taps. More if within a complex
system.
(see appendix 6 & 30 MSPT 21) by the WQ-MTC Contractor. Records are to be returned
electronically to E&F.
Monitoring and maintenance of cold water tanks is described in (Appendix 3).
To include cold water storage tanks fitted to water heaters.
Recorded information must be returned electronically to E&F for on-going management.
The entire cold water system must be subject to chlorination every 2 years. The
procedure is shown in (Appendix 9 MSPT1 and Appendix 10 MSPT1a).
Where temperature control is identified as poor, alternative means of control will be
undertaken.
Tank turnover
Use flow meter to determine actual usage over 12 hours, and adjust tank capacity to suit
recommendation storage capacity.
Page 15 of 103 February 2016 review – Legionella Control – University of Reading
4.5
Infrequently Used Outlets
Risk
A disused or low use of an outlet, will allow localised stagnation of water within the
pipework. Stagnation results in higher cold water temperature due to warming, and lower
hot water temperature due to cooling, resulting in water temperatures which are ideal for
legionella growth.
Control
Water outlets that are unused for 7 days or more, must be flushed for 5 minutes on a
weekly basis (see Appendices 8 and 19 MSPT 8). Identification of such low use outlets
can be during risk assessment, routine monitoring or by information provided by site.
This is particularly applicable to areas such as disabled toilets.
The flushing can be undertaken by staff from one of:
• WQ-MTC Contractor.
• E&F (Estates and Facilities)
Emergency showers and eyewash sprays, which are low use, will be subject to 3 monthly
flushing or as recommended by risk assessment. Records will be returned electronically
to E&F.
Areas which are disused, but still hold water within the system are considered as a
deadleg. Such unused or redundant pipework will be removed as soon as is practicable or
drained down and clearly identified.
The following vacation arrangements have been made for some Academic Buildings,
which will be unoccupied during holiday periods. L8 recommends that low use outlets
are flushed weekly. Due to the high numbers of rooms in these building, the University of
Reading will carry out the following procedures during holiday periods and other low use
periods to ensure L8 compliance:
•
•
•
•
Flush the far ends of each floor on a weekly basis
Increase sampling for Legionella
Report to E&F if there is a change of use.
Recording will be conducted electronically.
Recorded information must be returned to Legionella Duty Holder for on-going
management.
Page 16 of 103 February 2016 review – Legionella Control – University of Reading
4.6
Drinking Water Distribution
Risk
Generally, the risk of Legionellosis is low, but can become significant in large water
systems where, due to low use, stagnation can occur with warming because of poor
lagging/location of pipework. This results in water temperatures in the 20-45°C range,
control is required to ensure good through flow.
Control
Drinking water and drink dispensers should only be attached to the rising main, where
possible. Supply from tank/s should be avoided but where not possible potable water
must be appropriately labelled.
Tank supplied water (deemed drinking water quality by E&F, i.e. boosted) shall be
monitored and tested 6 monthly. (amplified in 4.17)
Drinking water outlets are to be located in designated areas and must be suitably
labelled “Drinking Water”.
The drinking water main, where reasonably practicable, is to supply at its extremity a
urinal-flushing cistern, (or similar) programmed for 7-day operation in order to prevent
water stagnation.
No alterations or additions to the drinking water supply can be made without written
agreement from the E&F Legionella Duty Holder.
E&F must be notified by schools/department of any equipment that requires permanent
fixture to the water supply.
4.7
Water Filters
Risk
Resin beds in water filters can act as a reservoir for bacteria and if breakthrough occurs,
the supply system downstream may be contaminated with Legionella and other bacteria.
Control
For water filters, the regeneration period must be known and the service visits must be
within a set period or as specified by the manufacturer (the usual period of change for
domestic units is 6 monthly).
If installed by Department, then departmental responsibility, otherwise the responsibility
of E&F. Recorded information must be returned electronically to Legionella Duty Holder
for on-going management.
Page 17 of 103 February 2016 review – Legionella Control – University of Reading
4.8
Stored Water Heaters:
Risk
Generally the risk is low but growth of legionella bacteria can occur where the
temperatures are constantly maintained at 20-45°C.
Control
Heaters with no storage: check for operation during risk assessment and bi yearly.
Heaters with up to 15 litres storage but with no header: Operate and maintain heater at
50-60°C. Temperature monitoring of these units will be conducted 3 monthly and
adjusted to supply water at 50-60°C where appropriate.
Heaters with more than 15 litres and header tank: If holding tanks are fitted then the tank
lid must be secured and the overflow screened. Temperature monitoring of these units
will be conducted monthly and adjusted to supply water at 50-60°C where appropriate.
Combination Heaters with header tank: Tank lid must be secured and the overflow
screened. Check internal condition, and temperature monitoring of these units will be
conducted monthly and adjusted to supply water at 50-60°C where appropriate.
(Appendix 21 MSPT10a)
If installed by Department, then departmental responsibility, otherwise the responsibility
of E&F. Recorded information must be returned electronically to Legionella Duty Holder
for on-going management.
4.9
Vending Machines:
Risk
Generally the risk from Legionella is low, but other bacteria must be kept from
proliferating by maintaining suitable temperatures within the units.
Control
The hot water supply temperature must be >70°C and the cold <10°C to meet the
recommendations in the Automatic Vending Association (GB) Code of Practice. If filters
are fitted to the cold water supply to the unit, these should be changed in accordance
with manufacturer’s recommended frequency. Vending machines must be supplied via a
suitable potable source ensuring the length of pipework from the source (tee off point)
for supply is as small as possible.
If installed by Department, then departmental responsibility, otherwise the responsibility
of E&F. Recorded information must be returned electronically to Legionella Duty Holder
for on-going management.
Page 18 of 103 February 2016 review – Legionella Control – University of Reading
4.10
Water Softeners:
Risk
Resin beds in softeners can act as a reservoir for bacteria and if breakthrough occurs, the
supply system, downstream, may be contaminated with Legionella and other bacteria.
Control
Hard/soft water checks should be carried out as required (normally at least weekly by the
DLO) and recorded. The maintenance contract details should be available, which must
include a periodic service/clean as indicated by the manufacturer of the unit or
disinfection if necessary. The brine tank should be kept in clean condition and the
softener back washed regularly preferably one backwash cycle in a day.
If installed by Department, then departmental responsibility, otherwise the responsibility
of E&F. Recorded information must be returned electronically to Legionella Duty Holder
for on-going management.
4.11
Fogging and Misting Systems (including horticultural misting systems)
Risk
A high level of spray/misting occurs when such systems are operated resulting in aerosol
formation. There will also be periods of low use and therefore stagnation. The aim of the
maintenance is to prevent stagnation.
Control
Glass houses around the University premises are fitted with fogging and misting systems.
a) Where UV lamps are fitted for bacterial control, the systems must be checked
and serviced according to manufacturers’ instructions (usually 6 monthly)
b) The water from the units must be automatically purged as part of shut down
c) All wetted areas must be subject to disinfection as per risk assessment
d) Legionella sampling must be conducted as indicated by risk assessment
If installed by Department, then departmental responsibility, otherwise the responsibility
of E&F. Recorded information must be returned electronically to Legionella Duty Holder
for on-going management.
4.12
Materials in contact with water
Risk
Materials not approved by a Water Research Advisory Centre (WRAS) testing laboratory
may provide nutrients to support microbiological growth.
Control
The best method to ensure compliance is to select products from the WRAS (Water
Fittings and Materials Directory). Jointing materials such as natural rubber, hemp and
linseed oil-based jointing compounds and fibre washers must not be used.
(see Appendix 1)
Page 19 of 103 February 2016 review – Legionella Control – University of Reading
4.13
Legionella Sampling
Risk assessment at all sites will determine if Legionella testing is required. Generally,
sampling may be conducted at larger Academic sites. Where sampling is undertaken,
single samples will be collected from each hot and cold water system. Guidance is given
in the appendix on interpretation of results. (see Appendix 28 MSPT19)
4.14
Fume Cupboards with Scrubber Units
Quarterly measure tank temperature and note tank condition.
Quarterly collect legionella sample.
For each bank of fume cupboards only one tank should be left operational. Other units
must be drained down.
If installed by Department, then departmental responsibility, otherwise the responsibility
of E&F. Recorded information must be returned electronically to Legionella Duty Holder
for on-going management.
4.15
Thermostatic Mixing Valves (TMV’s)
Conduct annual service if directed by Legionella Duty Holder.
Open and clean, replace defective parts and descale filter. Conduct fail safe test (type
dependent)
If installed by Department, then departmental responsibility, otherwise the responsibility
of E&F. Recorded information must be returned electronically to Legionella Duty Holder
for on-going management.
4.16
Sampling of boosted/tanked water for drinking purposes
Risk assessment at all sites will determine if boosted/tanks water feed all outlets including
drinking water outlets for a site. Where tank water is found to be the supply of drinking
water the following minimum sampling will be undertaken. Sample should be collected
from the source tank and a furthest outlet. The samples will be subject to the following
analysis: TVC, Coliforms and E.Coli.
If installed by Department, then departmental responsibility, otherwise the responsibility
of E&F. Recorded information must be returned electronically to Legionella Duty Holder
for on-going management.
Page 20 of 103 February 2016 review – Legionella Control – University of Reading
4.17
Expansion Vessels
Risk
Water stagnation within the expansion vessel at constant pressure. Lining may not be
WRAS approved material.
In recognition that water stagnation and particulate accumulation can have
detrimental effects upon water quality it is recommended that any fitting on a
wholesome water system which accommodates expansion or pressure surges, such
as expansion vessels, pressure accumulators and surge arrestors, be installed so as
to avoid localised low turnover (stagnation) leading to the formation of biofilms
and/or the accumulation of particulates. That is to say be installed in the vertical
so that the fitting accommodating thermal expansion or a pressure surge is
Control
Where practical, flush through and purge to drain, as indicated by the risk assessment.
Where new expansion vessels are installed, ensure stop and drain off valves are fitted.
<10 litre expansion vessels:
Fit drain cock and stop valve, if not fitted, but flushing to be conducted only if poor
microbiological results are recorded
>10 litre expansion vessels:
Fit drain cock and stop valve, if not fitted, conduct annual flush through and purge
through drain.
Installation
1. Bottom fed and upright.
2. That the connecting pipework to the fitting :- rises continuously
- is kept to a minimum
Sized
3. Sized correctly for the system
System design
4. Designed to ensure an adequate turnover of water within the fitting.
Page 21 of 103 February 2016 review – Legionella Control – University of Reading
Examples of good practice for the installation of fittings accommodating thermal
expansion or pressure surges
Installation:
Orientation: Bottom fed and upright √
Connecting pipework:
-
Rises continuously √
Is kept to a minimum √
Fitting: Sized correctly for the system √
System: Designed to ensure adequate turnover
of water within the fitting. √
Examples where the installation of fittings to accommodating thermal expansion
or pressure surges may have detrimental effects upon water quality, either
because of the orientation of the fitting or design of the connecting pipework, and
should be avoided.
Orientation: Bottom fed and
upright √
Connecting pipework:
- Rises continuously x
- Is kept to a minimum x
Indicates those areas where there is the potential for low turnover which could
result in the formation of biofilms and accumulation of particulates.
Orientation: Bottom fed and upright x
Connecting pipework:
- Rises continuously x
- Is kept to a minimum √
Page 22 of 103 February 2016 review – Legionella Control – University of Reading
Orientation: Bottom fed and upright x
Connecting pipework
-
Rises continuously x
Is kept to a minimum x
Orientation: Bottom fed and upright x
Connecting pipework
-
Rises continuously x
Is kept to a minimum √
Orientation: Bottom fed and upright x
Connecting pipework
-
Rises continuously x
Is kept to a minimum x
Indicates those areas where there is the potential for low turnover which could result in
the formation of biofilms and accumulation of particulates.
(see Appendix 31a MSPT23)
4.19
Dental Equipment
Risk
High level of spray/aerosol near nose and mouth, which could cause legionellosis.
Control
Normal Dentistry practice to conform to Decontamination (Health Technical
Memorandum 01-05, Decontamination in primary care dental practices)
Check at 6 monthly intervals and record.
Page 23 of 103 February 2016 review – Legionella Control – University of Reading
5.0 MANAGEMENT PROCEDURE
General
E&F will store water records electronically for each building. Records for all control
measures implemented, will be stored.
These will be held in the E&F building and will contain the following:
- Risk assessment for the system
- Schematic diagrams of the system
- Records of control checks taken
- Disinfection record certificates
- Records of any remedial work carried out
Audit procedures will be applied using in-house and/or external auditors. The
Responsible Person will oversee the audit.
Water Quality Measured Term Contract (WQ-MTC) Contractor
WQ-MTC water quality contractor will carry out disinfections/s, risk assessment/s,
schematic/s, sampling, monitoring, shower cleaning and other legislative works ensuring
L8 compliance for the University.
Reporting
All reports will be sent electronically to Legionella Duty Holder from the WQ-MTC
contractor. The actions will be checked and authorised. Remedial works will be
authorised and WRENs (Internal Work Orders) will be produced, where required.
Monthly Management Meeting
The outcome of defects, non-compliance and any other issues relating to water systems
within the University of Reading will be reviewed at the monthly WQ-MTC Legionella
meeting. Actions undertaken will be recorded where necessary and minutes will be taken
at the meeting.
Records
Estates and Facilities
Records for legionella management are stored in the following manner
a)
THE UNIVERSITY’S ELECTRONIC SYSTEM
This is an electronic system of data storage which allows data entry at the time of
inspection. It is the system operated by the MTC contractor. The data is stored
electronically (requires password entry for authorised personnel). All records are
stored within this system.
b)
WEB PORTAL
All risk assessments, schematics and disinfection certificates and any other record
provided will be stored as PDF files and are available for inspection through a web
portal to authorised staff.
Page 24 of 103 February 2016 review – Legionella Control – University of Reading
Individual University of Reading Schools/Departments/Directorates
Will ensure departmental equipment is serviced (including inspection, cleaning and
disinfecting) and maintained to the standard required to control legionella bacteria. (see
Appendix 47)
Individual Schools/Departments/Directorates will ensure records of servicing and
maintenance are kept for at least 5 years. Records to be available for audit when
requested.
6.0 SPECIFIC NON-COMPLIANCE PROCEDURE
Water Temperature
Non compliances are assessed and prioritised by the Legionella Duty Holder, on a day to
day basis and action is taken accordingly. (see Appendix 45)
Tanks and Calorifiers
Non compliances are assessed and prioritised by the Legionella Duty Holder, on a day to
day basis and actions are taken accordingly.
(see Appendix 45)
Legionella – Action Level Guidance
Legionella testing will be conducted as and when necessary or if indicated by risk
assessment. Typically, one hot water and one cold water sample will be collected from a
single building. Action on the Legionella results should be considered in relation to the
numbers of samples collected, the locations and the system particulars at the time of the
results. (see Appendix 46)
Action in the Event of Adverse Media Reports Regarding Legionella
If Legionella or other microbiological testing results are reported in the local or national
media, then the following procedure must be followed:
1. Inform the University Communications Manager as soon as possible with as much
information as possible, so they can prepare a statement for the press.
2. Do not speak to the press but guide them to the Communications Manager.
Page 25 of 103 February 2016 review – Legionella Control – University of Reading
7.0 PROCEDURES FOR PROJECTS
All new water systems or modifications will be designed, constructed and installed in
accordance with current legislation (see Appendix 1).
In order to ensure a consistent and compliant standard of delivery for all University of
Reading projects, all final disinfection, risk assessment and sampling to project related
works must be undertaken by the WQ-MTC Contractor.
It will be the responsibility of the Principal or Main Contractors to facilitate all the
necessary arrangements with the WQ-MTC Contractor, in accordance with the current
agreed schedule of rates (available from E&F Legionella Duty Holder).
Project Managers to liaise with E&F Legionella Duty Holder when unusual or minor
domestic alterations are carried out. At a minimum compliance with BS EN 806-5:2012
Specifications for installations inside buildings conveying water for human consumption.
8.0 TRAINING
Staff involved in the management of water systems will be trained by a competent person
to carry out their responsibilities.
The following training modules will be available for staff:
•
•
•
•
Training on all aspects of Legionella control.
Training for specific monitoring i.e. temperature testing, shower cleaning and
flushing low use outlets.
Legionella Duty Holder will arrange training for E&F.
Health and Safety Services will arrange training for Schools and other Directorate
staff.
Page 26 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 1
RELEVANT LEGISLATION, GUIDANCE AND STANDARDS
Health and Safety at Work etc. Act 1974 places general duties on employers and self-employed
persons to ensure, so far as is reasonably practicable, the health, safety and welfare of all their
employees, and persons other than their employees who may be affected by any of their
undertakings. Employers must also ensure that the premises, and any plant or substance therein,
are safe and present no risks.
Relevant legislation, guidance and standards to manage Legionella are set out below.
HSE Approved Code of Practice ACOP L8 2013 ~ The control of legionella bacteria in water
systems. Provides technical guidance on the management of water systems for Legionella
control.
Legionnaires' disease - Technical guidance - HSG274
The guidance is in three parts:
Part 1: The Control of Legionella Bacteria in Evaporative Cooling Systems.
Part 2: The Control of Legionella Bacteria in Hot and Cold Water Systems.
Part 3: The Control of Legionella Bacteria in Other Risk Systems.
BS EN 806-5:2012~ has been written in the form of a practice specification. It is the fifth part of
BS EN 806 "Specifications for installations inside buildings concerning water for human
consumption" which consists of five parts:
•
•
•
•
•
Part 1: General
Part 2: Design
Part 3: Pipe sizing — Simplified method
Part 4: Installation
Part 5: Operation and maintenance.
Control of Substances Hazardous to Health Regulations 2002 (as amended)
Apply to substances that are hazardous to health, including asbestos, and place specific
responsibilities on employers, self-employed persons and employees. The regulations require a
‘suitable and sufficient’ assessment to be made of the risks and measures necessary to control
substances hazardous to health arising from work. Employers are also required to maintain the
control measures to provide information, instruction and training in relation to the risks and
control measures; to monitor exposure of the employees to the substances and (where relevant)
organise a health surveillance programme.
Page 27 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 1 (Cont’d)
Water Supply (Water Fittings) Regulations 1999
With guidance from Water Regulations Advisory Scheme (WRAS) – provides an explanation of
the water fittings regulations. Part of the WRAS guidance is provided in the Water Fittings and
Material Directory which has information on materials which have been tested
microbiologically and chemically and have been found to be appropriate for use with water
systems.
Water Supply (Water Quality) Regulations 2010
Provides water suppliers with statutory limits on water quality with information on sampling,
testing and monitoring frequency.
Private Water Supplies Regulations 2009 (with amendments)
Provides private water suppliers with statutory limits on water quality with information on
sampling, testing and monitoring frequency.
Private Water Supplies Regulations 2009 Memo
Changes to Private Water Regulations 2009
BS8580 2010 Water Quality – risk assessment for Legionella control – Code of Practice
Provides recommendations for risk assessment for legionella control in artificial water systems,
covering the preparations, desktop appraisal, site visit/survey, reporting and review.
Page 28 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 2
KEY CONTACT DETAILS
Title
Duty Holder
Key Contact
Colin Robbins
Contact numbers
Tel : 0118 378 8277
Fax: 0118 378 6928
Email:
c.robbins@reading.ac.uk
Legionella
Duty Holder/
Responsible
Person
Shane Benson
Assistant Contracts Manager
Tel : 0118 378 8274
Fax: 0118 378 6928
Mob: 07540803142
Email:
s.c.benson@reading.ac.uk
Water Quality
Consultant/s
(Deputy
Responsible
Person)
Girish Mistry
Water Scientific Ltd
9 Trafford Road,
Reading
RG1 8JP
Tel: 0118 9453078
Fax: 0118 9428897
Mobile: 07973 254578
Email:
girish@waterscientific.co.uk
WQ-MTC
Contractor
SMS Environmental
Tel: 01189 306348
Fax:01189 306349
WQ-MTC
Contractor
On Site
Supervisor
Paul Dickinson
Tel:07739 084890
Email p.dikinson@smsenvironmental.co.uk
Page 29 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 3
REQUIREMENTS - COLD WATER TANKS
Area
Tanks <1000 litres
Action
Storage Tanks are to be inspected annually by WQ-MTC
contractor with consideration to thermal insulation, lid
condition, cleanliness, ball valve operation, overflow
condition and general condition. Water temperature from
the ball valve and tank must be tested.
Tanks >1000 litres
Storage Tanks are to be inspected 6 monthly by WQ-MTC
contractor with consideration to thermal insulation, lid
condition, cleanliness, ball valve operation, overflow
condition and general condition. Water temperature from
the ball valve and tank must be tested.
Tanks in Domestic
Houses
Storage tanks in Houses to be inspected 2 yearly during risk
assessment by WQ-MTC contractor with consideration to
thermal insulation, lid condition, cleanliness, ball valve
operation, overflow condition and general condition. Water
temperature from the ball valve and tank must be conducted
Delay valves
Where possible tanks are filled with delayed action float
valves or in the case of pumped services conductivity rod
operated switches to allow for positive water displacement in
the tank.
New tanks
New tanks to be partitioned or bypass installed to allow for
the chlorination and cleaning of the tanks without
interrupting the cold water/hot water service to the building.
Where partitioned tanks are present, the procedure is to
operate both tanks together except during chlorination and
maintenance.
The incoming feed to the tank is at the opposite end to the
outgoing connections.
New tank should be GRP sectional tanks externally flanged
with integral insulation, and ditched bottom drain with a
suitably sized drain for ease of cleaning.
Page 30 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 4
RESPONSIBILITY FLOW CHART
DUTY HOLDER
Director of Estates
• Provide suitable and sufficient
resources
• Appoint through employment
the Legionella Duty Holder
LEGIONELLA DUTY HOLDER
Assistant Contracts Manager
• Ensure compliance with L8
• Appoint nominated consultants
• Appoint through tender
nominated WQ-MTC
contractor
• Oversee WQ-MTC contract
output
• Liaison with all Stakeholders
WQ-MTC
CONTRACTOR
•
•
•
Conduct risk assessments
Conduct routine monitoring
Conduct chlorination and
pasteurisation
• Conduct testing for water
quality
• Liaison with all Stakeholders
• Ensure L8 compliance
WATER QUALITY
CONSULTANT
• Provide advice on current legal
requirements
• Measure WQ-MTC contract
output
• Liaison with all Stakeholders
Page 31 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 5
PROCEDURE AND FORMAT FOR RISK ASSESSMENT
The risk assessment should be conducted as and when required, but UoR Policy requires it is
conducted at least 2 yearly.
Review previous risk assessment (if conducted) for any potential for exposure to legionella
The risk assessment must consider the following to identify if the water system is likely to create
risk
•
•
•
•
•
Water is stored or recirculated in the system
The water temperatures in all or some of the parts of the system may be between 2045˚C
There are deposits that support bacterial growth, including legionella, such as rust,
sludge, scale, organic matter and biofilms
Is it possible for water droplets to be produced and if so whether they can be dispersed
Is it likely that any employees, contractors, visitors, the public etc.. could be exposed to
contaminated water droplets
The practical risk assessment must consider other Health and Safety risks.
The following type of reporting is required for all sites. Each risk assessment must of a similar or
equivalent format.
Section 1:
Front page with dated photograph of site. Indicating risk level and general
description of site services
Section 2:
Asset Register
Listing of all assets
Section 3:
Schematic
To show the face view of building (or best angle)
Assets to be shown in locality of view or angle
Schematics to include
1. Staircases
2. Lift shafts
3. Any features which may identify location of plant
4. Entrance to building
5. Valves to be shown, on all water plant, attached to system where seen.
(including water meters, Non return valves, zonal valves etc.)
6. Sentinels and other key outlets as specified to be identified on schematic with
bar code in legend.
7. Location of incoming mains and isolation valve.
8. Generally all items concerned with the water system must be included in the
schematic (e.g. softeners, filters, expansion vessels, tmv etc..)
9. Schematics to be in unlocked pdf and skf format.
Example schematic has been provided.
10. Tank access location.
Page 32 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 5 (Cont’d)
Section 4:
Cold Water storage details
Description and detail of cold water storage including photographs
Section 5:
Hot water storage details
Description and detail of hot water storage including photographs
Section 6:
Temperatures
All sentinel taps to be measured for temperature. Additionally, in a large
building water temperature to be taken from hot and cold water services from 20%
of the site water outlets.
Section 7:
Hazard & Controls.
Location, description and actual amounts required e.g. remove deadleg (how long,
size of pipework, type of pipework, access, etc.) Include dated pictures of each
hazard with reference number
Section 8:
Operating and Maintenance Procedures
To be retained, but for each building only retain those services required.
Section 9:
Water Regulations
To be the same format as hazards and controls, but to include if wastage, misuse,
contamination, L8 non-conformance. Include pictures of each hazard with
reference number.
Priority
1
2
3
Section 10:
Description
Serious non-compliance
Significant non-compliance
General non-compliance
Immediate rectification
Urgent rectification
Planned rectification
Photographs
Ensure all other photos taken have date, location and description labelled
correctly.
Page 33 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 6
PROCEDURE FOR TEMPERATURE MONITORING
Ensure all equipment used for temperature monitoring is calibrated appropriately and
calibration certificates are current
Expectations
The hot water should be greater than 50 ˚C and less than 60˚C
The cold water should be less than 20˚C
Hot water
Run water from tap for 1 minute
(at the fastest flow possible without causing high level of splashing or aerosols)
Record water temperature
The hot temperature should be between 50-60˚C
Cold water
Run water from tap for 2 minutes
(at the fastest flow possible without causing high level of splashing or aerosols)
Record water temperature
The cold temperature should be below 20˚C
Flow and return from calorifiers
Where fitted with gauges on the flow and return
Record the temperature indicated on the gauge
Periodically check gauge reading by testing with a contact thermometer
If the gauge reading is +/-3˚C, report to Duty Holder
Where no gauges are fitted, test using a contact thermometer
Record flow and return temperatures when the temperature has stabilised.
The hot water temperature at the flow should be 50-60˚C
The hot water temperature at the return should be +/-10˚C of the flow temperature
TMV supplied taps and outlets
Run water from outlet to be tested (at the hottest setting) until the water temperature stabilises
Record water temperature
Pipe temperature may be required if the TMV tap is a sentinel.
Select pipework to be measured.
Ensure the surfaces are bare metal.
Contact temperature probe to pipework (hot or cold) and hold until steady temperature is
noted, while flushing the tap continuously
The blended water temperature should be in the range 38-44˚C
Temperature monitoring from outlets is conducted monthly (sentinels) and Annually
(representative) from each system. In large water systems, numerous sentinels may be tested.
Where temperatures are below expectations (non-compliance), then a report should be
submitted to the Duty holder
Page 34 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 7
PROCEDURE FOR PASTEURISATION
Complete H&S Risk assessment – implement appropriate safe systems of work. WQ-MTC to
liaise with Legionella Duty Holder detailing the impact on site of procedure to be carried out
Warning notices to be placed in all appropriate places before work commences
Adjust temperature control of the hot water vessel to achieve a homogeneous temperature
throughout the vessel of >70°C
Complete temperature profile of vessel – record results
If it is not possible to maintain a homogenous temperature of >70°C for a period of 1 hour and
sequentially pasteurise all outlets, then report as non-compliance and complete a chemical
disinfection of the vessel in accordance with BS6700: 1997 subject to customer approval
Where it is possible to maintain a homogenous temperature of >70°C for a period of 1 hour and
sequentially pasteurise all outlets, then maintain temperature at >70°C for a period of one hour,
ensure all anti-stratification and secondary return pumps are operational throughout the
process
After the calorifier has been disinfected for an hour, sequentially run each hot water outlet fed
from the calorifier for 5 minutes: ensuring the temperature recorded does not fall below 60°C
After all outlets have been pasteurised, reduce the temperature of the vessel and outlets by
flushing water to waste – ensure temperatures are just <60°C before running to service
Remove all warning notices and return system to service
Supply details to Legionella Duty Holder and record any non-compliance for monthly report
Page 35 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 8
PROCEDURE FOR FLUSHING AND PURGING INFREQUENTLY USED OUTLETS
The water systems at the University are regularly maintained by Estates, and are operated at
temperatures to provide conditions that prevent the growth of the bacteria that cause
legionnaires disease. However, there is a possibility that the bacteria might start to grow in parts
of the water system when not in regular use.
L8 indicates that any outlet not used for 1 week (7 days) must be flushed. The flushing should be
conducted weekly.
When flushing a low use point bear in mind that the first quantity of water might be
contaminated. Once this water has run through the risk is minimized. Therefore it is the first 30
seconds to 1 minute when the risk is greatest and it is essential that staff avoid contact with
spray from outlets during this first flush through. Avoid contact with spray during other times
where possible
Flushing
When flushing showerheads and taps that have not been used for 7 days or more it is the first
quantity of water that might be contaminated. Once this water has run through the risk is
minimized. Therefore it is the first 30 seconds to 1 minute when the risk is greatest and it is
essential that staff avoid contact with spray from outlets during this first flush through. Avoid
contact with spray during other times where possible.
Showers
Run water from both hot and cold supplies, or warm if on a single mixer tap, through the
showerhead for 5 minutes if not in use for a period of 7 days. Showerheads are designed to
produce spray, which is why they should be run through a bucket of water so that no spray
escapes into the atmosphere. In the absence of a bucket of water take showerhead off the
bracket, and if possible lay it in the bath or shower tray before turning the taps on very low so
that water flows gently out of it. If this is not possible point it into the base of the shower tray or
bath. After 1 minute, the flow rate can be increased. If the showerhead is fixed, run the shower
head very slowly for 1 minute then increase the flow for a further 4 minutes.
Taps
Run water from both hot and cold supplies, or warm if on a single mixer tap, through tap(s) for 5
minutes, if not in use for a period of 7 days. The water should be run slowly to avoid spray for 1
minute and can then run faster for a further 4 minutes.
Page 36 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 8 (Cont’d)
Purging
Where it is difficult to carry out weekly flushing, the outlet concerned needs to be purged to
drain before the outlet is used normally. Therefore the following procedure should be utilised:
Open the outlet slowly at first.
It is important that this is done with the minimum production of spray.
it may be necessary to use additional piping to purge to drain if it is envisaged that spray may be
produced.
Run the outlet for 5 minutes before using the outlet.
Records should be kept detailing the time, date, location and name of the person who carried
out the purging procedure.
It is envisaged that this procedure will only apply to outlets that are in areas difficult to access
regularly and that all of the accessible outlets will be flushed weekly.
Difficulties
When flushing or purging outlets, any difficulties or problems encountered should be noted in
the comments section of the ‘infrequently used outlet’ log sheet and a remedial job raised via
the Maintenance Services helpdesk for the outlet concerned.
Recording
Records should be kept detailing the time, date, location and name of the person who carried
out the purging procedure either manually or electronically
Page 37 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 9
PROCEDURE ~ CHLORINATION
(TANKS, CALORIFIERS and DOWN SERVICES) (MSPT1)
The procedure for cleaning and disinfecting, complete hot and cold water system within the
building.
1.
WQ-MTC contractor to report to Legionella Duty Holder and to complete any necessary
permits to work documentation.
2.
Complete health and safety risk assessment and confirm if Confined Space Regulations
1997 apply – implement appropriate safe systems of work from WQ-MTC health and safety
manual. Works Supervisor to inform relevant personnel that down water facilities may be
interrupted.
3.
Boilers to be turned off/isolated and calorifier temperature suitable to chlorinate.
4.
Warning notices and ‘DO NOT USE’ tape must be in place on all water outlets before work
commences.
5.
Identify foul drainage and mark up, surface water drainage must not be used for flushing of
tank.
6.
Close down service and make-up valves to the CWS tank.
7.
Take dated photographs of tank internal condition before and after chlorination.
8.
Drain the tank(s) using appropriate valve(s), (check oxygen levels of water within tank if
necessary).
9.
Mechanically clean out the tanks as thoroughly as possible (use extraction as required)
swabbing sides (non-abrasive material) to remove any biofilm.
10. When cleaning complete, refill the tank with water and add dose sodium hypochlorite to
achieve a free chlorine reserve of 50 mg/l. When chlorine is used as the disinfection agent,
measure pH of the treated water to ensure it does not exceed 8.0 (refer to attached chart
for the effect of pH on the efficacy of the chlorine). Chlorine concentration and pH to be
measured in the stored water and sentinel outlets using a calibrated photometer, a
comparator or an appropriate drop test kit to ensure exact measurement of chlorine
concentration is achieved.
11. All outlets should be opened and run to ensure chlorine is distributed throughout the
system (hot and cold water systems). Outlets other than sentinel outlets are to be tested on
the high range potassium iodide paper until a dark blue colouration is achieved on the test
paper.
12. When appropriate chlorine concentration is achieved at all terminal fittings, the outlets
should be closed ensuring warning label or tape still in place clearly indicating that the
facility is not to be used.
13. Do not allow the storage tank to empty during step 8 (or draw air into system).
Page 38 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 9 (cont’d)
14. The entire system must be left to soak as stipulated by BS6700: 1997 and the HSC’s
Approved Code of Practice L8 – A minimum 1 hour contact period is to be achieved whilst
ensuring the free chlorine concentration does not fall below 50 mg/l either at the CWS
tanks, calorifiers or outlets. Record level of free chlorine after the 1hr period. Repeat
disinfection will be required if the free chlorine level drops below 30mg/l. Inform Duty
Holder if this occurs.
15. After the contact period of 1 hour is achieved, neutralise the disinfectant with Sodium
Thiosulphate, drain the tank to foul sewer, then thoroughly flush tank and refill with fresh
water.
16. Open the outlets, and flush system until chlorine concentration equals that of the incoming
mains water, taking care not to empty the tank or draw air into the system. Remove warning
labels.
17. Clean top of CWST/s and ensure all bolts have been fastened and lid/s sealed.
18. If required take water samples as detailed in work instruction and submit to approved UKAS
laboratory.
19. Leave working area clean and tidy.
EFFECT OF pH
WATER STORAGE TANK CLEANING AND DISINFECTION INCLUDING DOWN WATER SERVICES
HOCI
H*
OCI-
Hypochlorous Acid
Hydrogen Ion
Hypochlorite Ion
Killing Agent
Inactive, but stable form
Active, but unstable form
% Chlorine as HOCI
pH
% Chlorine as OCI-
90
6.5
10
73
7.0
27
66
7.2
34
45
7.6
55
21
8.0
79
10
8.5
90
Page 39 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 10
PROCEDURE ~ DISINFECTION USING PEROXIDE
(TANKS, CALORIFIERS and DOWN SERVICES) (MSPT1A)
The procedure for cleaning and disinfecting a water storage tank will vary from one installation
to another. The details outlined below are specific and apply to the majority of systems.
Supplementary detail would be included in the Work Instruction, which would accompany this
document.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
WQ-MTC contractor to report to Legionella Duty Holder and to complete any necessary
permits to work documentation.
Complete health and safety risk assessment and confirm if Confined Space Regulations
1997 apply – implement appropriate safe systems of work from WQ-MTC health and safety
manual. Works Supervisor to inform relevant personnel that down water facilities may be
interrupted.
Warning notices and ‘DO NOT USE’ tape must be in place on all water outlets before work
commences.
Close down service and make-up valves, to the CWS tank.
Drain the tank(s) using appropriate valve(s), (check oxygen levels of water within tank if
necessary).
Take dated photographs of tank internal condition before and after chlorination.
Mechanically clean out the tanks as thoroughly as possible (use extraction as required)
swabbing sides (non-abrasive) to remove any biofilm.
When cleaning is complete, refill the tank with water and add dose Peroxide to achieve a
reserve of 50 mg/l.
All outlets should be opened and run to ensure peroxide is distributed throughout the
system (hot and cold water system). All outlets are to be tested and verified.
When appropriate peroxide concentration is achieved at all terminal fittings, the outlets
should be closed ensuring warning label’s or tape are still in place clearly indicating that the
facility is not to be used.
Do not allow the storage tank to empty, or draw air into system.
The entire system must be left to soak as stipulated by BS6700: 1997 and the HSC’s
Approved Code of Practice L8 – A minimum 1 hour contact period is to be achieved whilst
ensuring the disinfectant level does not fall below 50 mg/l either at the CWS tanks,
calorifiers or outlets. Repeat disinfection may be required if the disinfectant drops
significantly. Consultation with Legionella Duty Holder will be required.
After the contact period of 1 hour is achieved, drain the tank to foul sewer, then thoroughly
flush tank and refill with fresh water.
Open the outlets, and flush system until peroxide level drops to near zero. Remove
warning labels and tape.
Clean top of CWST/s and ensure all bolts have been fastened and lid is sealed.
If required take water samples as detailed in work instruction and submit to approved
UKAS laboratory.
Leave working area clean and tidy.
Page 40 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 11
PROCEDURE ~ FULL RISK ASSESSMENT AND SCHEMATICS (MSPT2)
The following type of reporting is required for all sites. Each risk assessment must be of a
similar or equivalent format.
Section 1:
Front page with dated photograph of site. Indicating risk level and general
description of site services.
Section 2:
Asset Register
List all assets. (And must be all shown on schematic)
Section 3:
Schematic
To show the face view of building (or best angle)
Assets to be shown in locality of view or angle
Schematics to include:1.
Staircases.
2.
Lift shafts.
3.
Any features which may identify location of plant.
4.
Entrance to building.
5.
Valves to be shown, on all water plant, attached to system where seen.
(including water meters, Non return valves, zonal valves etc.)
6.
Sentinels and other key outlets as specified to be identified on schematic
with bar code in legend.
7.
Location of incoming mains and isolation valves.
8.
Generally all items concerned with the water system must be included in
the schematic (e.g. softeners, filters, expansion vessels, TMV’s, dead legs,
showers etc.)
9.
Schematics to be in unlocked pdf and original CAD format.
Example schematic has been provided.
10.
Tank access location.
Section 4:
Cold Water storage details
Description and detail of cold water storage, including photographs.
Section 5:
Hot water storage details
Description and detail of hot water storage, including photographs.
Section 6:
Temperatures and Site inspection
All sentinel taps to be measured for temperature. Additionally, in a large building
water temperature to be taken from hot and cold water services from 20% of the
site water outlets. Record all other areas of concern.
Page 41 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 11(cont’d)
Section 7:
Hazard & Controls
Location, description and actual amounts required e.g. remove deadleg (how long,
size of pipework, type of pipework, access, etc.) Include dated pictures of each
hazard with reference number and budget costs for remedial works.
Section 8:
Operating and Maintenance Procedures
To be retained, but for each building only retain those services required.
Section 9:
Water Regulations
Same format as hazards and controls. To include if wastage, misuse,
contamination, L8 non-conformance. Include pictures of each hazard with
reference number and budget costs for remedial works.
Priority
1
2
3
Section 10:
Description
Serious non-compliance
Significant non-compliance
General non-compliance
Action
Immediate rectification
Urgent rectification
Planned rectification
Photographs
Ensure all other photos taken have date, location and description labelled.
Page 42 of 103 February 2016 review – Legionella Control – University of Reading
PROCEDURE ~ DESCALE CALORIFIER/BUFFER VESSEL
AND INSPECTION (MSPT3)
APPENDIX 12
1.
Attend site and complete any signing in of permit to works procedure.
2.
Complete a site risk assessment in the area of works and ensure all the requirements under
the COSHH 2002 regulations are applied and implement all necessary safe systems of work.
3.
Ensure that all operatives are wearing the PPE, appropriate for working with acidic
chemicals and that all equipment complies with the requirements of the Personal
Protective Equipment Regulations 2002.
4.
Post any necessary warning signs and labels – including ‘no smoking’ signs.
5.
Identify and mark foul sewer to which effluent is to be discharged – reference to site
drawings should be made – NEVER DISCHARGE TO A SURFACE WATER DRAIN.
6.
Ensure all permissions have been obtained from the water undertaker in order that
discharge of effluent can be made to the sewerage system.
7.
Inspect vessel to be de-scaled and ascertain material of manufacture so that the
appropriate descaling agent can be chosen:
a.
b.
c.
For mild steel, welded steel, or copper calorifiers, Hydrochloric acid should be used
(32% v/v) – dosage rate 10% of system volume.
For galvanised steel calorifiers use sulphamic acid (Ca 98%) inhibited with ethoxylated
amine for corrosion inhibition – dosage rate 10% of system volume.
For stainless steel vessels use Phosphoric acid (32%) – dosage rate 10% of system
volume - DO NOT USE HYDROCHLORIC ACID WITH STAINLESS STEEL.
When descaling with any acid, some hydrogen gas may be evolved. Hydrogen is a flammable gas,
and the working area should be well ventilated. Do not allow smoking or any other means of
ignition in the area of work.
8.
Disconnect or isolate cold water feed pipe – ensure all valves are holding.
9.
Disconnect or isolate flow pipe and seal off any secondary hot water return pipe – ensure
all valves are holding.
10.
Remove any sacrificial corrosion anodes, and blank off apertures.
11.
Electrically isolate vessel and implement lock off/ tag system to ensure electrical safety
(This may be fully disconnected by site depending on site policy).
12.
If there is a drain valve on calorifier, use this as pump connection point, in preference to the
water feed inlet. Check that valve is clear and will pass water through at a reasonable rate. If
necessary clear a passage through any blockage - there may be several inches of scale
accumulation on the base of a calorifier.
13.
Connect one de-scaled pump hose to the flow connection and one to the drain outlet (or
alternative).
Page 43 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 12 (cont’d)
14.
The pump connection to the lower point of the calorifier should always be through a valve.
Power failure to the de-scale pump would result in the head-of-water in the calorifier overflowing the de-scale pump tank; this can be prevented by closing the valve.
15.
Hose connections should be made so that there is a closed circuit between the pump flow
hose, through the calorifier, to the return hose. Venting of the carbon dioxide gas evolved
is achieved through the pump tank filler cap aperture. The filler cap should be screwed on
by no more than one quarter of a turn. This is sufficient to vent the gas, but at the same
time reduces fumes and prevents splashes.
16.
Connect the pump to a suitable earthed power supply - 110 Volt via a transformer. As the
pump will be used in a damp location, a residual current circuit breaker plug top should be
used.
flow and return tubing
hot water outlet
CALORIFIER
flow reverser
secondary
return
heating coil
cap
DESCALING PUMP
drain point
or valve
cold feed
flow and return tubing
Figure 1: Typical installation of descaling pump and tank.
Page 44 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 12 (cont’d)
17.
The flow reverser handle should point in the direction of flow of the liquid. Operate the
handle so that it initially points towards the hose connected to the base/drain valve of the
calorifier. The hose from the top of the calorifier will then be the return to the pump tank.
18.
Prior to adding descaling chemical to pump tank, first 'prove' the circuit with fresh water
alone. Add water to pump tank to approx. 8 cm above minimum liquid level, switch on
pump, and immediately open the calorifier drain valve to allow circulation to commence. If
water level drops initially, add more water to pump tank and check that all connections are
tight.
19.
To commence descaling, slowly add chosen descaling chemical into pump tank, waiting
until liquid is returning into the descaling pump tank from the water heater and check to
see if there is a rapid build-up of foam on top of the liquid in the pump. This may happen
when there is a large build-up of reactive limescale in the base of the calorifier. If this is
excessive, add a little anti-foam carefully to the pump tank to reduce the foam production.
20.
As the pumping commences, bubbles will be seen in the return hose to the pump,
indicating that limescale is being dissolved. Allow circulation through the calorifier and
descaling pump to continue, briefly reversing the direction of flow periodically.
21.
Check all connections regularly for tightness, and absence of leaks, and if foaming is
excessive, carefully remove descaling pump tank cap and add more anti-foam to the
descaling pump tank.
22.
A pH meter or pH indicator paper should be used to check the pH of the descaling effluent.
Once the pH has risen from 3.5 to 4, its ability to dissolve limescale is effectively spent and
more descaling chemical or a fresh solution will be required.
23.
The descaling procedure can be considered complete once the pH of the treated effluent
stabilises at a pH of <3, as the neutralising effect of the hardness salt deposits within the
vessel have all been used up and the effluent remains acidic.
24.
If, after descaling has ceased the pH of the descaling solution is still < 5, then the remaining
solution must be neutralised to bring the pH level above 5, and as close to 7 as practicable.
This may be done by slowly adding sodium carbonate crystals to the tank of the descaling
pump until there is no more effervescence as the crystals are added. If foaming is a problem
during this operation, add a few millilitres of antifoam.
25.
Check the pH of the descaling effluent once it has reached pH > 6.5 discharge to the
agreed foul sewer, flush the calorifier with fresh water. Many natural waters are slightly
alkaline, and therefore all that is needed is dilution to achieve a neutral pH within the
vessel. Alternatively, circulate a 1% solution of sodium carbonate through the
calorifier/Vessel for 15 minutes, drain, record time, and then flush with clean water once
more.
Page 45 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 12 (cont’d)
26.
At this stage any accessible calorifiers/vessels can be opened and internally inspected and
any sediment and solids that are not acid soluble can be removed by vacuuming from the
base of the vessel. Take dated photographs of the internal conditions of the vessel. Insert
new gasket material and reseal vessel checking all connections.
27.
Complete a thermal disinfection of the vessel in accordance with the requirements of the
HSC Code of Conduct L8. On completion go to representative outlets on the system and
test the pH for comparison with the pH of the incoming mains water supply to site. Flush all
outlets if necessary.
29.
Remove any warning signs and labels.
29.
Reinstate or replace as necessary any sacrificial anodes.
30.
Re-instate pipe work and any electrically isolated switches and controls.
31.
Sign off any permits to works and record any discharge consent requirements.
32.
Liaise with the point of contact on site and sign off all work sheets.
33.
Provide all results in form of inspection report complete with dated photographs and
certification.
34.
Leave working area clean and tidy.
Page 46 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 13
PROCEDURE ~ TANK INSPECTION
DOMESTIC SYSTEM (MSPT4a)
1
Take temperature at the ball valve and from the body of the water within the tank.
2
Internal inspection is carried out to determine the condition of the tank.
3
Internal condition, such as corrosion, sediment, slime must be reported.
4
Assess if complete turnover of water is occurring within 12 hours.
5
External inspection is carried out to confirm that the tank overflow is screened as is the
warning pipe (if fitted), the lagging is well fitted and generally the tank is compliant with
WRAS requirements.
6
Report is provided of the condition and with recommendations for improvement where
required. Urgent recommendations are conveyed verbally and confirmed by email
immediately.
7
Provide within report dated photographs of internal and external condition of CWST.
8
Clean top of CWST/s and ensure all bolts have been fastened and lid sealed.
9
Leave working area clean and tidy.
Page 47 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 14
PROCEDURE ~ TANK INSPECTION
TANKS <1000 litres (MSPT4b)
1
Take temperature at the ball valve and from the body of the water within the tank.
2
Internal inspection is carried out to determine the condition of the tank.
3
Internal condition, such as corrosion, sediment, slime must be reported.
4
Assess if complete turnover of water is occurring within 12 hours.
5
External inspection is carried out to confirm that the tank overflow is screened as is the
warning pipe (if fitted), the lagging is well fitted and generally the tank is compliant with
WRAS requirements.
6
Report is provided of the condition and with recommendations for improvement where
required. Urgent recommendations are conveyed verbally and confirmed by email
immediately.
7
Clean top of CWST/s and ensure all bolts have been fastened and lid sealed.
8
Provide within report dated photographs of internal and external condition of CWST.
9
Leave working area clean and tidy.
Page 48 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 15
PROCEDURE ~ TANK INSPECTION
TANKS >1000 litres (MSPT4c)
1
Take temperature at the ball valve and from the body of the water within the tank.
2
Internal inspection is carried out to determine the condition of the tank.
3
Internal condition, such as corrosion, sediment, slime must be reported.
4
Assess if complete turnover of water is occurring within 12 hours.
5
External inspection is carried out to confirm that the tank overflow is screened as is the
warning pipe (if fitted), the lagging is well fitted and generally the tank is compliant with
WRAS requirements.
6
Report is provided of the condition and with recommendations for improvement where
required. Urgent recommendations are conveyed verbally and confirmed by email
immediately.
7
Clean top of CWST/s and ensure all bolts have been fastened and lid sealed.
8
Provide within report dated photographs of internal and external condition of CWST.
9
Leave working area clean and tidy.
Page 49 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 16
PROCEDURE ~ TANK INSPECTION AND SAMPLING (MSPT5)
TANK INSPECTION
1
Take temperature at the ball valve and from the body of the water within the tank.
2
Internal inspection is carried out to determine the condition of the tank.
3
Internal condition, such as corrosion, sediment, slime must be reported.
4
Assess if complete turnover of water is occurring within 12 hours.
5
External inspection is carried out to confirm that the tank overflow is screened as is the
warning pipe (if fitted), the lagging is well fitted and generally the tank is compliant with
WRAS requirements.
6
Report is provided of the condition and with recommendations for improvement where
required. Urgent recommendations are conveyed verbally and confirmed by email
immediately.
7
Clean top of CWST/s and ensure all bolts have been fastened and lid sealed.
8
Provide within report dated photographs of internal and external condition of CWST.
9
Leave working area clean and tidy.
TANK SAMPLING
The analysis conducted is Total Viable Count at 22°C and 37°C, Coliforms and E.Coli. The analysis
is a general suite used for drinking water and provides suitable information of water condition.
Sample is collected in the following manner:1
2
3
4
5
6
Remove or open tank lid.
Take the lid of a sterile sample bottle and place carefully to prevent contamination.
Hold the body of the bottle and tip forward – dip into water within the tank.
Move forwards with the bottle opening leading – fill entire bottle.
Tip out water within the neck and replace cap.
Keep bottle cool (4°C) and return to laboratory within 24 hours for analysis.
E.Coli and Coliforms are reported the next day and Total Viable Counts within 3 days.
Urgent recommendations are conveyed verbally and confirmed by email immediately.
Page 50 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 17
PROCEDURE ~ CHECKING TMV FAIL SAFE (MSPT6)
Thermostatic mixing valves must be tested to determine if very hot water can be supplied to the
outlet.
The following should be conducted:1.
Turn off the cold supply to the TMV.
2.
Wait a few seconds and check if there is flow at the outlet.
3.
If the hot water is above 50˚C, then there should be no flow.
4.
Fail safe check is considered satisfactory.
5.
If the hot water is below 47˚C then there will be a flow and the fail safe check is
considered complete, a repeat test will be required.
6.
Repeat test should be conducted when the supply temperature is above 50˚C, when
during cold shut off no water should be flowing from the outlet.
7.
If hot water flows from the outlet during cold shut off above.
8.
Report any non-conformances on TMV to Legionella Duty Holder.
9.
Leave all working area clean and tidy.
Page 51 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 18
PROCEDURE ~ SHOWER HEAD CLEANING (MSPT7)
1.
Remove and dismantle shower head. Clean off any large particles and deposits.
2.
Wear gloves, goggles and other appropriate PPE.
3.
Soak showerhead and hose (if fitted) in Sulphamic acid solution (A) until scale deposits
removed.
4.
Rinse in clean water and brush off any remaining deposits.
5.
Soak in chlorinated water solution (B) for 5 minutes.
6.
Rinse in clean water.
7.
Reassemble shower head and reconnect to hose.
8.
Turn on shower and run for 2 minutes at maximum temperature.
9.
Following flushing complete a test of the water from the shower. pH should be equal to
that of the incoming main. Free chlorine concentration should be <1.0 mg.L-1prior to
returning the shower to service.
10. Leave working area clean and tidy.
NOTES
a) Solution (A) = Dissolve approximately 50g full Sulphamic Acid Powder to 1 litre hot water.
Allow to cool and store in sealed labelled* plastic container. Depending on shower
contamination the solution may be reused several times. (*Labelled “Sulphamic Acid
solution -ACID/CORROSIVE”).
b) Solution (B) = Dilute 10 ml Sodium Hypochlorite [stock solution?] in 1 litre cold water.
(14% strength will produce approx. 1400 mg.L-1 free chlorine.) Depending on
contamination this solution may be reused several times. Store in sealed plastic container
(preferably black, and labelled STRONG OXIDISING AGENT”: Do not mix with acid).
c) The shower hose fitting may also benefit from cleaning in the same way.
d) It is essential to rinse the shower head and container following the acid stage BEFORE
immersing. Failure to do so will result in DANGEROUS GASES being given off.
e) Take care to avoid splashes of both solutions.
Care should be taken with metal finished components as prolonged contact with either solution
may tarnish them.
Page 52 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 19
PROCEDURE ~ FLUSHING INFREQUENTLY USED OUTLETS (MSPT8)
When flushing showerheads, spray taps and taps that have not been used for 2 weeks or more
first quantity of water might be contaminated. Once this water has run through the risk is minimal.
Therefore it is the first 30 seconds to 1 minute when the risk is greatest and it is essential to avoid
contact with spray from outlets during this first flush through.
Showers
Run water from both hot and cold supplies, or warm if on a single mixer tap, through the
showerhead for 5 minutes. Showerheads are designed to produce spray, which is why they should
be run through a bucket of water so that no spray escapes into the atmosphere.
In the absence of a bucket of water take showerhead off the bracket, and if possible lay it in the
bath or shower tray before turning the taps on very low so that water flows gently out of it. If this
is not possible point it into the base of the shower tray or bath. After 1 minute, the flow rate can
be increased. If the showerhead is fixed, run the shower head very slowly for 1 minute then
increase the flow for a further 4 minutes.
Taps
Run water from water supplies (both hot and/or cold supplies), or warm if on a single mixer tap,
through tap(s) for 5 minutes. The water should be run slowly to avoid spray for 1 minute and can
then run faster for a further 4 minutes. Record temperature at first instance and again after 5 mins
and record.
Regular flushing through on a weekly basis should ensure that any contamination that might occur
is kept at a low level. Where it is difficult to carry out weekly flushing, that the outlet concerned
needs to be purged to drain before the outlet is used normally.
Therefore the following procedure should be utilised:
1. Identify little used outlets as specified and verified from risk assessment.
2. Open the outlet slowly at first. It is important that this is done with the minimum
production of spray. It may be necessary to use additional piping to purge to drain if it is
envisaged that spray may be produced.
3. Run the outlet for 5 minutes before using the outlet.
4. It is envisaged that this procedure will only apply to outlets that are in areas difficult to
access regularly and that all of the accessible outlets will be flushed weekly.
5. Records should be kept detailing the time, date, location and name of the person who
carried out the purging/flushing procedure.
6. Leave working area clean and tidy.
When flushing the outlets, any difficulties or problems encountered (low flow, low pressure,
intermittent flow etc.) should be noted and brought to the attention of the Legionella Duty
Holder.
Page 53 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 20
PROCEDURE ~ WATER FILTER CHANGE (MSPT9)
1.
Works Supervisor to report to Site Manager and to complete any necessary permits to
work documentation.
2.
Complete health and safety risk assessment and confirm if Confined Space Regulations
1997 apply.
3.
Isolate electrical supply to unit via fused spur.
4.
Isolate mains water supply to unit via isolation valve.
5.
Locally isolate filter and remove.
6.
Install new filter. For inline filter assemblies a directional arrow on the body of the filter
denotes the flow of supply water.
7.
For inline filter assemblies connect the supply side pipe work only and direct the open end
of the filter into an appropriate receptacle.
8.
Reinstate water supply and flush filter until discharge water is clear in appearance.
9.
Isolate mains water supply and connect post filter pipe work.
10.
Reinstate mains water supply.
Cartridge Type Assemblies
1
2
3
4
5
Once new filter is installed, reinstate mains water supply and flush through cold outlet tap
until discharge water is clear in appearance.
Label new filter with current date and date of next replacement using permanent marker
pen.
Reinstate mains water supply to unit and check integrity of isolation valves.
Reinstate electrical supply to unit.
Apply maintenance label to unit denoting:
a) Job number
b) Current Date
c) Date of next service
6
7
Leave working area clean and tidy.
Dispose of spent filter/s in line with Environmental Policy disposal recommendations.
Page 54 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 21
PROCEDURE ~ STORAGE WATER HEATERS (MSPT10a)
1.
Up to 15 litres (changed from 20 litres) storage but with no header.
2.
Check for operation between 50oc -60oc.
3.
Temperature monitoring of these units will be every 3 months.
4.
Notify Legionella Duty Holder of non-compliance.
5.
Leave working area clean and tidy.
1.
More than 15 litres.
2.
Check for operation between 50oc -60oc.
3.
Temperature monitoring of these units will be monthly.
4.
Notify Legionella Duty Holder of non-compliance.
5.
Leave working area clean and tidy.
1.
Combination water heaters with header tank.
2.
Check for operation between 50oc -60oc.
3.
Temperature monitoring of these units will be monthly.
4.
Annually check lid is secure and overflow screened, check internal condition of tank. Check
for evidence of hot water flow back into tank
5.
Notify Legionella Duty Holder of non-compliance.
6.
Leave working area clean and tidy.
Page 55 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 22
PROCEDURE ~ INSTANTANEOUS WATER HEATERS (MSPT10b)
1.
With no storage.
2.
Check for operation.
3.
Temperature monitoring of these units will be bi annual. These will be checked during the
two yearly risk assessment and alternate years.
4.
Notify Legionella Duty Holder of non-compliance.
5.
Leave working area clean and tidy.
Page 56 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 23
PROCEDURE ~ LEGIONELLA TRAINING (MSPT11)
1
Assist the University in assessing the training requirements for the University’s employees.
To be used at the University’s discretion.
2
Provide the required expertise for the necessary Legionella awareness training for the
University’s staff.
3
Design to help raise awareness of Legionnaires disease by explaining how outbreaks might
occur, and highlighting water systems that have a potentially high risk of developing the
Legionella bacterium.
4
Provide information on the relevant legislation and requirements for compliance, and
suitable for all staff :(a)
(b)
(c)
(d)
(e)
Project staff
Direct Employed Labour
Building Managers
Cleaning staff
Other relevant groups
5
On successful completion, learners will have an increased understanding of Legionnaires'
disease, including the potential consequences of an outbreak and the symptoms
associated with the disease.
6
Employees should have an understanding of the importance in their roles within the
University.
Page 57 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 24
PROCEDURE ~ WATER SOFTENER (DISINFECTION) (MSPT12)
1
Ensure compliance with COSHH assessment.
2
Agree the method of works with the client or client’s representative and complete any
required permits prior to any work being commenced.
3
Isolate/Close outlet valves from softener.
4
If necessary by-pass the equipment to sustain services. Ensure that hand isolating valves
are fully closed for the duration of the disinfection process.
5
Backwash the equipment thoroughly for 15 minutes.
6
Introduce a solution of NaOCL (Chlorine) at 0.3% - 0.5% with respect to available
chlorine, educted through the injection system.
Note! The quantity required will be approximately 2% by volume of available resin.
7
8
Monitor the effluent from the system at the drain point and record the level of chlorine.
Isolate the equipment and shut down for a period of 60 minutes.
9
Thoroughly flush the system to remove excess chlorine and test at the drain to less than
1.0 p.p.m or the equivalent level provided by the water supplier.
10
Fully regenerate the system prior to reinstatement to service.
11
Certification is issued following disinfection, detailing the time and date of these works,
and identifying the specification used.
12
Leave working area clean and tidy.
Page 58 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 25
PROCEDURE ~ FOGGING AND MISTING SYSTEMS (DISINFECTION) (MSPT13)
1.
WQ-MTC contractor to report to Legionella Duty Holder and to complete any necessary
permits to work documentation.
2.
Complete health and safety risk assessment and confirm if Confined Space Regulations
1997 apply – implement appropriate safe systems of work from WQ-MTC health and safety
manual. Works Supervisor to inform relevant personnel that down water facilities may be
interrupted.
3.
Warning notices and ‘DO NOT USE’ tape must be in place on all water outlets before work
commences.
4.
Close down service and make-up valves.
5.
Locate the injection point for chlorinated solution. Pump into system using appropriate
equipment.
6.
All outlets should be opened and run to ensure chlorine is distributed throughout the
system (cold water system).
7.
When appropriate chlorine concentration is achieved at all terminal fittings, the outlets
should be closed ensuring warning label’s or tape are still in place, clearly indicating that
the facility is not to be used.
8.
The entire system must be left to soak as stipulated by BS6700: 1997 and the HSC’s
Approved Code of Practice L8 – A minimum 1 hour contact period is to be achieved whilst
ensuring the free chlorine concentration does not fall below 50 mg/l either at the CWS
tanks, calorifiers or outlets. Repeat disinfection may be required if the free chlorine level
drops significantly. Consultation with Duty Holder will be required.
9.
After the contact period of 1 hour is achieved, neutralise the disinfectant with Sodium
Thiosulphate, drain the tank to foul sewer, then thoroughly flush tank and refill with fresh
water.
10.
Open the outlets and flush system until chlorine concentration equals that of the incoming
mains water. Remove warning labels.
11.
If required take water samples as detailed in work instruction and submit to approved
UKAS laboratory.
For more information on chlorination see MSPT1
Page 59 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 26
PROCEDURE ~ FOGGING AND MISTING SYSTEMS (SERVICE) (MSPT14)
Glass houses with fogging and misting systems.
1.
Where UV lamps are fitted for bacterial control, the systems must be checked and serviced
according to manufacturers’ instructions (usually 6 monthly). The service may involve the
changing of the UV lamp and changing of filters.
2.
The water from the units must be automatically purged as part of shut down.
3.
Operate system; ensuring sufficient flow through is occurring. Check the UV Lamp is
operational and adequate flow-through is occurring through the filter.
4.
Legionella sampling must be as required as indicated by risk assessment. See MSPT19.
5.
Leave working area clean and tidy.
Page 60 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 27
PROCEDURE ~ EMERGENCY EYEWASH AND EMERGENCY SHOWERS (MSPT18)
1.
Remove and dismantle eyewash or emergency shower. Clean off any large particles and
deposits.
2.
Soak eyewash or emergency shower and hose (if fitted) in Sulphamic acid solution (A) until
scale deposits removed.
3.
Wear gloves and goggles.
4.
Rinse in clean water and brush off any remaining deposits.
5.
Soak in chlorinated water solution (B) for 5 minutes.
6.
Rinse in clean water.
7.
Reassemble shower head and reconnect to hose.
8.
Turn on eyewash or emergency shower and run for 2 minutes and record water
temperature.
9.
Following flushing, complete a test of the water from the eyewash or emergency shower.
pH should be equal to that of the incoming main. Free chlorine concentration should be
<1.0 mg.L-1prior to returning the shower to service.
10.
Leave working area clean and tidy.
NOTES
Solution (A) = Dissolve approximately 50g full Sulphamic Acid Powder to 1 litre hot
water. Allow to cool and store in sealed labelled* plastic container. Depending on shower
contamination the solution may be reused several times. (*Labelled “Sulphamic Acid
solution -ACID/CORROSIVE”).
Solution (B) = Dilute 10 ml Sodium Hypochlorite [stock solution] in 1 litre cold water.
(14% strength will produce approx. 1400 mg/l -1 free chlorine.) Depending on
contamination this solution may be reused several times. Store in sealed plastic container
(preferably black, and labelled STRONG OXIDISING AGENT”: Do not mix with acid).
The shower hose fitting may also benefit from cleaning in the same way.
It is essential to rinse the shower head and container following the acid stage BEFORE
immersing.
Failure to do so will result in DANGEROUS GASES being given off.
Take care to avoid splashes of both solutions.
Care should be taken with metal finished components as prolonged contact with either
solution may tarnish them.
Page 61 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 28
PROCEDURE ~ LEGIONELLA SAMPLING (MSPT19)
Sampling to be conducted from sites as required or notified by Legionella Duty Holder. Each
individual system is to be sampled. Usually 1 sample is collected from each system.
1 sample from cold water
1 sample from hot water
Sample collection
Cold water
1.
2.
3.
4.
5.
Hot water
1.
2.
3.
4.
5.
Flush tap to be sampled for 2 minutes.
Record water temperature.
Take the lid off a sterile sample bottle and place carefully to prevent
contamination.
Fill bottle to the neck and replace lid.
Keep bottle at room temperature and supply to the laboratory within 24 hours of
taking sample.
Flush tap to be sampled for 1 minute.
Record water temperature.
Take the lid off a sterile sample bottle and place carefully to prevent
contamination.
Fill bottle to the neck and replace lid.
Keep bottle at room temperature and supply to the laboratory within 24 hours of
taking sample.
Reporting
Legionella analysis takes up to 10 days for completion. However laboratories regularly inspect
the plates and interim reports are issued.
Where interim reports are issued it means there is Legionella present in the sample. The receipt
of such as result is forwarded immediately to the Legionella Duty Holder.
Report to show the following information:a)
Location
b)
Date of test
c)
Time of test
d)
System (Hot or Cold)
e)
Name of Operative
f)
Recommendations
The action required is determined by the Duty Holder, dependant on system operating
information, temperature at the time of testing and on the type of Legionella Species present.
Page 62 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 29
PROCEDURE ~ BACTERIAL SAMPLING (MSPT20)
The analysis conducted is Total Viable Count at 22°C and 37°C, Coliforms and E.Coli. The analysis
is a general suite used for drinking water and provides suitable information of water condition.
Varying numbers of samples are collected depending on the size and systems within the
University. Samples are collected as below.
1.
2.
3.
4.
5.
Flush tap to be sampled for 2 minutes.
Record water temperature.
Take the lid off a sterile sample bottle and place carefully to prevent
contamination.
Fill bottle to the neck and replace lid.
Keep bottle at chilled or at 4°C and supply to the laboratory within 24 hours of
time of sample.
Reporting
The laboratory provides results as soon as they are available. E.Coli and Coliforms are reported
the next day and Total Viable Counts within 3 days. Poor results must be reported to the
Legionella Duty Holder.
Urgent recommendations are conveyed verbally and confirmed by email immediately.
Report to show the following information:a)
Location
b)
Date of test
c)
Time of test
d)
System
e)
Name of Operative
f)
Recommendations
The action required is determined by the Legionella Duty Holder.
Page 63 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 30
PROCEDURE ~ MONITORING OF TEMPERATURE FROM TAPS (MSPT21)
Select tap to be monitored (from risk assessment recommendations and schematic)
Ensure all equipment used for temperature monitoring is calibrated appropriately and
calibration certificates are current
Expectations
The hot water should be greater than 50 ˚C and less than 60˚C
The cold water should be less than 20˚C
Hot water
Run water from tap for 1 minute
(at the fastest flow possible without causing high level of splashing or aerosols)
Record water temperature
The hot temperature should be between 50-60˚C
Cold water
Run water from tap for 2 minutes
(at the fastest flow possible without causing high level of splashing or aerosols)
Record water temperature
The cold temperature should be below 20˚C
Flow and return from calorifiers
Where fitted with gauges on the flow and return
Record the temperature indicated on the gauge
Periodically check gauge reading by testing with a contact thermometer
If the gauge reading is +/-3˚C, report to Duty Holder
Where no gauges are fitted, test using a contact thermometer
Record flow and return temperatures when the temperature has stabilized.
The hot water temperature at the flow should be 50-60˚C
The hot water temperature at the return should be +/-10˚C of the flow temperature
Page 64 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 30 (Cont’d)
TMV supplied taps and outlets
Run water from outlet to be tested (at the hottest setting) until the water temperature stabilizes
Record water temperature
Pipe temperature may be required if the TMV tap is a sentinel.
Select pipework to be measured.
Ensure the surfaces are bare metal.
Contact temperature probe to pipework (hot or cold) and hold until steady temperature is
noted, while flushing the tap continuously
The blended water temperature should be in the range 38-44˚C
Temperature monitoring from outlets is conducted monthly (sentinels) and Annually
(representative) from each system. In large water systems, numerous sentinels may be tested.
Where temperatures are below expectations (non-compliance), then a report should be
submitted to the Duty holder
Page 65 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 31
PROCEDURE ~ CALORIFIER TEMPERATURE MONITORING
(FLOW AND RETURN) (MSPT22)
1
Care should be taken when gaining access to the unit.
2
Record the ‘Set’ temperature setting of the thermostat. The temperature should be >60°C.
3
Measure the ‘Flow’ temperature using a calibrated contact thermometer or fitted gauge.
Temperature to be taken from ‘Flow’ pipework as close to the Calorifier as possible. The
temperature should be >60°C.
4
Measure the ‘Return’ temperature using a calibrated contact thermometer or fitted gauge.
Temperature to be taken from ‘Return’ pipework as close to the Calorifier as possible. The
temperature should be >50°C.
5
Ensuring safe and suitable drainage facilities are present, close the cold feed and open the
drain of the calorifier and flush until clear. Take the temperature of the drain water (closing
the cold feed will ensure that the temperature is taken from the base of the unit and not
from the higher pressure cold feed). Note the condition of the initial drain flush and
subsequent flush water.
6
Re-instate the cold feed to the system without delay.
7
Note base temperature.
8
Check the temperature to the cold feed to the calorifier using a calibrated contact
thermometer, noting if there is a non-return valve fitted. The temperature of the cold feed
should be <20°C at 1 meter from the unit.
Note:
If contact probe is to be used for temperature monitoring through copper
pipework, a +2oC temperature adjustment must be added to the recorded
temperature before reporting temperature on the Log-sheet.
Note:
The temperature measurements shall be carried out at different times during the
day in order to allow indicative temperature monitoring of the vessel during a
typical daily usage profile.
Page 66 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 31A
PROCEDURE ~ EXPANSION VESSEL INSPECTION (MSPT23)
1
Check condition of vessel
(Check for damage, dents, rusting, water marks from diaphragm entrance if possible)
2
Turn off pump set if applicable
3
Check vessel pressure (raise hazard if water emits)
4
5
Isolate and drain vessel as much as possible (if no drain or isolation valve raise hazard for
fitting)
Check air pressure with drain open to atmosphere
6
Recharge with nitrogen (OFN) to correct pressure
7
Record
Serial number
Dimensions (Length, breadth and max/min dia)
Capacity (estimated if not known)
Make and Model
Location
Pressure reading on vessel
Photograph of vessel
Photograph pressure gauge
8
Record all issues as hazards low, medium or high
9
Fitted correctly YES/ NO
Page 67 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 32
PROCEDURE ~ CHLORINATION
(TANKS, CALORIFIERS and DOWN SERVICES) (MSRT1)
The procedure for cleaning and disinfecting, complete hot and cold water system within the building.
1.
WQ-MTC contractor to report to Legionella Duty Holder and to complete any necessary
permits to work documentation.
2.
Complete health and safety risk assessment and confirm if Confined Space Regulations
1997 apply – implement appropriate safe systems of work from WQ-MTC health and safety
manual. Works Supervisor to inform relevant personnel that down water facilities may be
interrupted.
3.
4.
Boilers to be turned off/isolated and calorifier temperature suitable to chlorinate.
Warning notices and ‘DO NOT USE’ tape must be in place on all water outlets before work
commences.
5.
Identify foul drainage and mark up, surface water drainage must not be used for flushing of
tank.
6.
Close down service and make-up valves, to the CWS tank.
7.
Take dated photographs of tank internal condition before and after chlorination.
8.
Drain the tank(s) using appropriate valve(s), (check oxygen levels of water within tank if
necessary).
9.
Mechanically clean out the tanks as thoroughly as possible (use extraction as required)
swabbing sides (non-abrasive) to remove any biofilm.
10.
When cleaning complete, refill the tank with water and add dose sodium hypochlorite to
achieve a free chlorine reserve of 50 mg/l. When chlorine is used as the disinfection agent,
measure pH of the treated water to ensure it does not exceed 8.0 (refer to attached chart
for the effect of pH on the efficacy of the chlorine). Chlorine concentration and pH to be
measured in the stored water and sentinel outlets using a calibrated photometer, a
comparator or an appropriate drop test kit to ensure exact measurement of chlorine
concentration is achieved.
11.
All outlets should be opened and run to ensure chlorine is distributed throughout the
system (hot and cold water system). Outlets other than sentinel outlets are to be tested on
the high range potassium iodide papers until a dark blue colouration is achieved on the
test paper.
12.
When appropriate chlorine concentration is achieved at all terminal fittings, the outlets
should be closed ensuring warning label or tape still in place clearly indicating that the
facility is not to be used.
13.
Do not allow the storage tank to empty during step 8 (or draw air into system).
Page 68 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 32(cont’d)
14.
The entire system must be left to soak as stipulated by BS6700: 1997 and the HSC’s
Approved Code of Practice L8 – A minimum 1 hour contact period is to be achieved whilst
ensuring the free chlorine concentration does not fall below 50 mg/l either at the CWS
tanks, calorifiers or outlets. Record level of free chlorine after the hour period. Repeat
disinfection will be required if the free chlorine level drops below 30mg/l. Inform Duty
Holder if this occurs.
15.
After the contact period of 1 hour is achieved, neutralise the disinfectant with Sodium
Thiosulphate, drain the tank to foul sewer, then thoroughly flush tank and refill with fresh
water.
16.
Clean top of CWST/s and ensure all bolts have been fastened and lid sealed.
17.
Open the outlets, and flush system until chlorine concentration equals that of the
incoming mains water, taking care not to empty the tank or draw air into the system.
Remove warning labels and tape.
18.
If required take water samples as detailed in work instruction and submit to approved
UKAS laboratory.
19.
Leave working area clean and tidy
EFFECT OF pH
WATER STORAGE TANK CLEANING AND DISINFECTION INCLUDING DOWN WATER SERVICES
HOCI
H*
OCI-
Hypochlorous Acid
Hydrogen Ion
Hypochlorite Ion
Killing Agent
Inactive, but stable form
Active, but unstable form
% Chlorine as HOCI
pH
% Chlorine as OCI-
90
6.5
10
73
7.0
27
66
7.2
34
45
7.6
55
21
8.0
79
10
8.5
90
Page 69 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 33
PROCEDURE ~ DISINFECTION USING PEROXIDE
(TANKS, CALORIFIERS and DOWN SERVICES) (MSRT1a)
The procedure for cleaning and disinfecting a water storage tank will vary from one installation
to another. The details outlined below are specific and apply to the majority of systems.
Supplementary detail would be included in the Work Instruction, which would accompany this
document.
1.
WQ-MTC contractor to report to Legionella Duty Holder and to complete any necessary
permits to work documentation.
2.
Complete health and safety risk assessment and confirm if Confined Space Regulations
1997 apply – implement appropriate safe systems of work from WQ-MTC health and safety
manual. Works Supervisor to inform relevant personnel that down water facilities may be
interrupted.
3.
Warning notices and ‘DO NOT USE’ tape must be in place on all water outlets before work
commences.
4.
Close down service and make-up valves, to the CWS tank.
5.
Take dated photographs of tank internal condition before and after chlorination.
6.
Drain the tank(s) using appropriate valve(s), (check oxygen levels of water within tank if
necessary).
7.
Mechanically clean out the tanks as thoroughly as possible (use extraction as required)
swabbing sides (non-abrasive) to remove any biofilm.
8.
When cleaning complete, refill the tank with water and add dose Peroxide to achieve a
reserve of 50 mg/l.
9.
All outlets should be opened and run to ensure peroxide is distributed throughout the
system (hot and cold water system). All outlets are to be tested and verified.
10.
When appropriate peroxide concentration is achieved at all terminal fittings, the outlets
should be closed ensuring warning label or tape still in place clearly indicating that the
facility is not to be used.
11.
Do not allow the storage tank to empty, or draw air into system.
12.
The entire system must be left to soak as stipulated by BS6700: 1997 and the HSC’s
Approved Code of Practice L8 – A minimum 1 hour contact period is to be achieved whilst
ensuring the disinfectant level does not fall below 50 mg/l either at the CWS tanks,
calorifiers or outlets. Repeat disinfection may be required if the disinfectant drops
significantly. Consultation with Legionella Duty Holder will be required.
Page 70 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 33 (cont’d)
13.
After the contact period of 1 hour is achieved, drain the tank to foul sewer, then thoroughly
flush tank and refill with fresh water.
14.
Clean top of CWST/s and ensure all bolts have been fastened and lid sealed.
15.
Open the outlets, and flush system until peroxide level drops to near zero. Remove
warning labels and tape.
16.
If required take water samples as detailed in work instruction and submit to approved
UKAS laboratory.
17.
Leave working area clean and tidy.
Page 71 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 34
PROCEDURE ~ FULL RISK ASSESSMENT AND SCHEMATICS (MSRT2)
The following type of reporting is required for all sites. Each risk assessment must be of a similar
or equivalent format.
Section 1:
Front page with dated photograph of site. Indicating risk level and general
description of site services.
Section 2:
Asset Register
List all assets. (And must be all shown on schematic)
Section 3:
Schematic
To show the face view of building (or best angle).
Assets to be shown in locality of view or angle
Schematics to include:1.
Staircases.
2.
Lift shafts.
3.
Any features which may identify location of plant.
4.
Entrance to building.
5.
Valves to be shown, on all water plant, attached to system where seen.
(including water meters, Non return valves, zonal valves etc.)
6.
Sentinels and other key outlets as specified to be identified on schematic
with bar code in legend.
7.
Location of incoming mains and isolation valve.
8.
Generally all items concerned with the water system must be included in
the schematic (e.g. softeners, filters, expansion vessels, TMV’s dead legs,
showers etc).
9.
Schematics to be in unlocked pdf and original CAD format.
Example schematic has been provided.
10.
Tank access location.
Section 4:
Cold Water storage details
Description and detail of cold water storage including photographs.
Section 5:
Hot water storage details
Description and detail of hot water storage including photographs.
Section 6:
Temperatures and Site Inspection
All sentinel taps to be measured for temperature. Additionally, in a large building
water temperature to be taken from hot and cold water services from 20% of the
site water outlets. Record all areas of concern.
Section 7:
Hazard & Controls.
Location, description and actual amounts required e.g remove deadleg (how long,
size of pipework, type of pipework, access, etc) Include dated pictures of each
hazard with reference number, and budget costs for remedial works.
Page 72 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 34 (cont’d)
Section 8:
Operating and Maintenance Procedures
To be retained, but for each building only retain those services required.
Section 9:
Water Regulations
Same format as hazards and controls. To include if wastage, misuse,
contamination, L8 non-conformance. Include pictures of each hazard with
reference number, and budget costs for remedial works.
Priority
1
2
3
Section 10:
Description
Serious non-compliance
Significant non-compliance
General non-compliance
Action
Immediate rectification
Urgent rectification
Planned rectification
Photographs
Ensure all other photos taken have date, location and description labelled
correctly.
Page 73 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 35
PROCEDURE ~ CALORIFIER/BUFFER VESSEL DESCALE AND INSPECTION (MSRT3)
1.
Attend site and complete any signing in a permit to works procedure.
2.
Complete a site risk assessment in the area of works ensure all the requirements under the
COSHH 2002 regulations are applied and implement all necessary safe systems of work.
3.
Ensure that all operatives are wearing the PPE appropriate for working with acidic
chemicals, and that all equipment complies with the requirements of the Personal
Protective Equipment Regulations 2002.
4.
Post any necessary warning signs and labels – including ‘no smoking’ signs.
5.
Identify and mark foul sewer to which effluent is to be discharged – reference to site
drawings should be made – NEVER DISCHARGE TO A SURFACE WATER DRAIN.
6.
Ensure all permissions have been obtained from the water undertaker in order that
discharge of effluent can be made to the sewerage system.
7.
Inspect vessel to be de-scaled and ascertain material of manufacture so that the
appropriate descaling agent can be chosen:
a. For mild steel, welded steel, or copper calorifiers Hydrochloric acid should be used
(32% v/v) – dosage rate 10% of system volume.
b. For galvanised steel calorifiers use sulphamic acid (Ca 98%) inhibited with
ethoxylated amine for corrosion inhibition – dosage rate 10% of system volume.
c. For stainless steel vessels use Phosphoric acid (32%) – dosage rate 10% of system
volume - DO NOT USE HYDROCHLORIC ACID WITH STAINLESS STEEL.
When descaling with any acid, some hydrogen gas may be evolved. Hydrogen is a flammable gas,
and the working area should be well ventilated. Do not allow smoking or any other means of
ignition in the area of work.
8.
Disconnect or isolate cold water feed pipe – ensure all valves are holding.
9.
Disconnect or isolate flow pipe, and seal off any secondary hot water return pipe – ensure
all valves are holding.
10.
Remove any sacrificial corrosion anodes, and blank off apertures.
11.
Electrically isolate vessel and implement lock off/ tag system to ensure electrical safety
(This may be fully disconnected by site depending on site policy).
12.
If there is a drain valve on calorifier, use this as pump connection point, in preference to the
water feed inlet. Check that valve is clear and will pass water through at a reasonable rate. If
necessary clear a passage through any blockage - there may be several inches of scale
accumulation on the base of a calorifier.
Page 74 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 35 (cont’d)
13.
Connect one de-scaled pump hose to the flow connection, and one to the drain outlet (or
alternative).
14.
The pump connection to the lower point of the calorifier should always be through a valve.
Power failure to the de-scale pump would result in the head-of-water in the calorifier overflowing the de-scale pump tank, this can be prevented by closing the valve.
15.
Hose connections should be made so that there is a closed circuit between the pump flow
hose, through the calorifier, to the return hose. Venting of the carbon dioxide gas evolved
is achieved through the pump tank filler cap aperture. The filler cap should be screwed on
by no more than one quarter of a turn. This is sufficient to vent the gas, but at the same
time reduces fumes and prevents splashes.
16.
Connect the pump to a suitable earthed power supply - 110 Volt via a transformer. As the
pump will be used in a damp location, a residual current circuit breaker plug top should be
used.
flow and return tubing
hot water outlet
CALORIFIER
flow reverser
secondary
return
heating coil
cap
DESCALING PUMP
drain point
or valve
cold feed
flow and return tubing
Figure 1: Typical installation of descaling pump and tank.
Page 75 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 35 (cont’d)
17.
The flow reverser handle should point in the direction of flow of the liquid. Operate the
handle so that it initially points towards the hose connected to the base/drain valve of the
calorifier. The hose from the top of the calorifier will then be the return to the pump tank.
18.
Prior to adding descaling chemical to pump tank, first 'prove' the circuit with fresh water
alone. Add water to pump tank to approx. 8 cm above minimum liquid level, switch on
pump, and immediately open the calorifier drain valve to allow circulation to commence. If
water level drops initially, add more water to pump tank, and check that all connections are
tight.
19.
To commence descaling, slowly add chosen descaling chemical into pump tank, waiting
until liquid is returning into the descaling pump tank from the water heater, and check to
see if there is a rapid build up of foam on top of the liquid in the pump. This may happen
when there is a large build up of reactive limescale in the base of the calorifier. If this is
excessive, add a little anti-foam carefully to the pump tank to reduce the foam production.
20.
As the pumping commences, bubbles will be seen in the return hose to the pump,
indicating that limescale is being dissolved. Allow circulation through the calorifier and
descaling pump to continue, briefly reversing the direction of flow periodically.
21.
Check all connections regularly for tightness, and absence of leaks, and if foaming is
excessive, carefully remove descaling pump tank cap and add more anti-foam to the
descaling pump tank.
22.
A pH meter, or pH indicator paper, should be used to check the pH of the descaling
effluent. Once the pH has risen to 3.5 to 4, its ability to dissolve limescale is effectively
spent, and more descaling chemical or a fresh solution will be required.
23.
The descaling procedure can be considered complete once the pH of the treated effluent
stabilises at a pH of <3, as the neutralising effect of the hardness salt deposits within the
vessel have all been used up and the effluent remains acidic.
24.
If, after descaling has ceased, the pH of the descaling solution is still < 5, then the
remaining solution must be neutralised to bring the pH level above 5, and as close to 7 as
practicable. This may be done by slowly adding sodium carbonate crystals to the tank of
the descaling pump until there is no more effervescence as the crystals are added. If
foaming is a problem during this operation, add a few millilitres of antifoam.
25.
Check the pH of the descaling effluent once it has reached pH > 6.5 discharge to the
agreed foul sewer, flush the calorifier with fresh water. Many natural waters are slightly
alkaline, and therefore all that is needed is dilution to achieve a neutral pH within the
vessel. Alternatively, circulate a 1% solution of sodium carbonate through the
calorifier/Vessel for 15 minutes, drain, record time, and then flush with clean water once
more.
Page 76 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 35 (cont’d)
26.
At this stage any accessible calorifiers/vessels can be opened and internally inspected and
any sediment and solids that are not acid soluble can be removed by vacuuming from the
base of the vessel. Take dated photographs of the internal conditions of the vessel. Insert
new gasket material and reseal vessel checking all connections.
27.
Complete a thermal disinfection of the vessel in accordance with the requirements of the
HSC Code of Conduct L8. On completion go to representative outlets on the system and
test the pH for comparison with the pH of the incoming mains water supply to site. Flush all
outlets if necessary.
29.
Remove any warning signs and labels.
29.
Reinstate or replace as necessary any sacrificial anodes.
30.
Re-instate pipe work and any electrically isolated switches and controls.
31.
Sign off any permits to works and record any discharge consent requirements.
32.
Liaise with the point of contact on site and sign off all work sheets.
33.
Provide all results and certification.
34.
Leave working area clean and tidy.
Page 77 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 36
PROCEDURE ~ REMOVE CWS TANK(s), REPLACE WITH GRP or PLASTIC TANK
to the Water Supply (Water Fittings) Regulations, 1999 Standard (MSRT4)
The University is committed to replace domestic cold water storage tanks to the standard
required by the Water Supply (Water Fittings) Regulations, 1999.
The preferred tank design is pre-insulated GRP fibre-glass. The domestic cold water storage tanks
must:
1.
WQ-MTC contractor to report to Legionella Duty Holder and to complete any necessary
permits to work documentation.
2.
Complete health and safety risk assessment and confirm if Confined Space Regulations
1997 apply – implement appropriate safe systems of work from WQ-MTC health and safety
manual. Works Supervisor to inform relevant personnel that down water facilities will be
interrupted.
3.
Isolate, drain down and disconnect existing cwst/s and remove from site.
4.
Supply and fit complete new cwst/s to be:-
5.
Appropriately sized for the demand.
6.
Shall be of the pre-insulated GRP / fibre-glass type.
7.
Have a tight fitting cover, with an access hatch if greater than 1000 litres. Again the hatch
should be secure and tight fitting, but either that hatch or cover should be easy to open for
inspection / cleaning etc (i.e. thumb screws or similar.
8.
There shall be a screened air inlet in the cover. The screen is to be corrosion resistant
and the mesh size should be smaller than 0.65mm mesh.
9.
It is recommended that ( if present) the domestic hot water vent should be to an open
tundish to drain and not into the tank.
10. The tank should be fitted with a lowest point drain / washout pipe (especially if greater
than 1000 litres in capacity).
11. The tank should be mounted on a flat surface that is suitable to carry the total weight
without deflection.
12. There are to be service valves fitted on the incoming mains supply and all outgoing downservice / flow pipes.
13. Where practicable single tanks only shall be fitted. If absolutely necessary multiple tanks
shall be fitted in parallel. Tanks shall NOT be fitted in series.
Page 78 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 36 (cont’d)
14. An insect screen is to be fitted on the overflow. The screen is to be corrosion resistant
and the mesh size should be smaller than 0.65mm mesh. Allowance must be made in
sizing to ensure that the screen will pass the same amount of water as the warning and / or
overflow pipe.
15. Float operated valves and other fittings for controlling flow of mains water make-up into
cold water tanks will comply with the requirements of Schedule 2, section 16 of the ‘Water
Supply (Water Fittings) Regulations, 1999’. They shall also comply with the relevant
British Standards (e.g. BS 1212, BS 1968, BS 2456
16. Clean and Chlorinate tank as MSRT4a.
17. Leave working area clean and tidy.
Page 79 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 37
PROCEDURE ~ CHLORINATION FOR CWS TANK/s (MSRT4a)
The procedure for cleaning and disinfecting a water storage tank will vary from one installation to
another. The details outlined below are specific and apply to the majority of systems.
Supplementary detail would be included in the Work Instruction, which would accompany this
document.
1
WQ-MTC contractor to report to Legionella Duty Holder and to complete any necessary
permits to work documentation.
2
Complete health and safety risk assessment and confirm if Confined Space Regulations
1997 apply – implement appropriate safe systems of work from WQ-MTC health and safety
manual. Works Supervisor to inform relevant personnel that down water facilities may be
interrupted.
3
Identify foul drainage and mark up, surface water drainage must not be used for flushing of
tank.
4
Close down service and make-up valves, to the CWS tank.
5
Drain the tank(s) using appropriate valve(s), (check oxygen levels of water within tank if
necessary).
6
Mechanically clean out the tanks as thoroughly as possible (use extraction as required)
swabbing sides (non-abrasive)to remove any biofilm.
7
When cleaning complete, refill the tank with water and add dose sodium hypochlorite to
achieve a free chlorine reserve of 50 mg/l. When chlorine is used as the disinfection agent,
measure pH of the treated water to ensure it does not exceed 8.0 (refer to attached chart
for the effect of pH on the efficacy of the chlorine). Chlorine concentration and pH to be
measured in the stored water, a comparator or an appropriate drop test kit to ensure exact
measurement of chlorine concentration is achieved.
8
After the contact period of 1 hour is achieved, neutralise the disinfectant with Sodium
Thiosulphate, drain the tank to foul sewer, then thoroughly flush tank and refill with fresh
water.
9
Clean top of CWST/s and ensure all bolts have been fastened and lid sealed.
10
If required take water samples as detailed in work instruction and submit to approved
UKAS laboratory.
11
Leave working area clean and tidy.
Page 80 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 37 (cont’d)
EFFECT OF pH
HOCI
H*
OCI-
Hypochlorous Acid
Hydrogen Ion
Hypochlorite Ion
Killing Agent
Inactive, but stable form
Active, but unstable form
% Chlorine as HOCI
pH
% Chlorine as OCI-
90
6.5
10
73
7.0
27
66
7.2
34
45
7.6
55
21
8.0
79
10
8.5
90
Page 81 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 38
PROCEDURE ~ CHLORINATION USING FOGGING EQUIPMENT (MSRT4b)
The disinfection of vessels using the fogger is acceptable where constraints dictated by
environmental or site condition or available time renders traditional methods impractical.
To disinfect the internal surfaces using a fine mist droplet. The vessel interior is filled with a fine
mist of disinfectant solution; tiny droplets wet the internal surfaces, providing a disinfectant film
which, after a suitable contact time effects the disinfection.
1
All preparatory work should be complete, i.e. draining, swabbing, and hosing down etc in
order to provide “clean” surfaces to all parts of the tank.
2
Position the fogger, and connect up to electrical supply using circuit
breaker/transformer/leads without causing a trip hazard.
3
Fill the fogger tank with the required disinfectant solution.
4
Place the fogger hose into the vessel and switch the fogger on (do not put fogger into
vessel).
5
Confirm correct operation, and adjust the output nozzle to desired setting.
6
Close the vessel access, and allow the mist to fill the vessel completely. If possible carry out
visual checks on progress of mist formation.
7
When production of mist complete, switch the fogger off. Allow the vessel to stand for one
hour minimum contact time.
8
On completion of contact time remove equipment, open lids and depending on site
conditions either hose down the internals, or fill the vessel with fresh water, and return to
service.
9
Leave working area clean and tidy.
Page 82 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 39
PROCEDURE ~ TMV SERVICE AND FAILSAFE (MSRT5)
1.
Mark the site address, the Job number, the date, the location and the type of TMV.
2.
Wear gloves, goggles and other appropriate PPE.
3.
Remove and dismantle TMV including Valve mechanism, strainers, Non-return valves and
isolation valves (If practicable). Clean off any large particles and deposits.
4.
Soak in Sulphamic acid solution (A) until scale deposits removed.
5.
Rinse in clean water and brush off any remaining deposits.
6.
Soak in chlorinated water solution (B) for 5 minutes.
7.
Rinse in clean water.
8.
Reassemble TMV and replace ‘O’ ring gasket if required.
9.
Turn on isolation valves and open outlet and run for 2 minutes then record mixed water
temperature.
10. Isolate cold water supply to test the cold water failsafe. If hot water continues to flow to the
outlet, then TMV has failed and will require a replacement. If the hot water has stopped, the
TMV has passed the failsafe check, and may now resume normal service.
11. Record Temperature from incoming hot water.
12. Following flushing complete a test of water from the TMV. pH should be equal to that of the
incoming main. Free chlorine concentration should be <1.0 mg.L-1prior to the outlet.
13. Check fail safe as MSPT6.
14. Leave working area clean and tidy.
Page 83 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 39 (cont’d)
NOTES
a)
Solution (A) = Dissolve ca 50g full Sulphamic Acid Powder to 1 litre hot water. Allow to
cool and store in sealed plastic container. Depending on TMV contamination the solution
may be reused several times. (Labelled “ACID/CORROSIVE”).
b)
Solution (B) = Dilute 10 mls Sodium Hypochlorite in 1 litre cold water. (14% strength will
produce approx. 1400 mg/l-1 free chlorine.) Depending on contamination this solution may
be reused several times. Store in sealed plastic container (preferably black, and labelled
“STRONG OXIDISING AGENT”).
c)
It is essential to rinse TMV and container following the acid stage BEFORE immersing.
Failure to comply will result in DANGEROUS GASES being given off.
d)
Take care to avoid splashes of both solutions.
e)
Care should be taken with metal finished components as prolonged contact with either
solution may tarnish them.
Page 84 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 40
PROCEDURE ~ DESCALE TAP/s (MSRT6)
1.
Arrange/Notify appropriate Building manager of works to be carried out.
2.
Use approved descaler/Gel and allow full hour contact time.
3.
Ensure inside of tap head is fully immersed/coated.
4.
Lightly abrade with plastic scourer/wipe clean scale sediment, ensuring no damage is
caused to tap.
5.
Stubborn scaling repeat above process.
6.
Rinse and wipe clean.
7.
Leave working area clean and tidy.
Page 85 of 103 February 2016 review – Legionella Control – University of Reading
PROCEDURE ~ WATER FILTER CHANGE (MSRT7)
APPENDIX 41
1.
Works Supervisor to report to Site Manager and to complete any necessary permits to
work documentation.
2.
Complete health and safety risk assessment and confirm if Confined Space Regulations
1997 apply.
3.
Isolate electrical supply to unit via fused spur.
4.
Isolate mains water supply to unit via isolation valve.
5.
Locally isolate filter and remove.
6.
Install new filter. For inline filter assemblies a directional arrow on the body of the filter
denotes the flow of supply water.
7.
For inline filter assemblies connect the supply side pipe work only and direct the open end
of the filter into an appropriate receptacle.
8.
Reinstate water supply and flush filter until discharge water is clear in appearance.
9.
Isolate mains water supply and connect post filter pipe work.
10.
Reinstate mains water supply.
Cartridge Type Assemblies
1.
Once new filter is installed, reinstate mains water supply and flush through cold outlet tap
until discharge water is clear in appearance.
2.
3.
Label new filter with current date and date of next replacement using permanent marker
pen.
Reinstate mains water supply to unit and check integrity of isolation valves.
4.
Reinstate electrical supply to unit.
5.
Apply maintenance label to unit denoting:
a.
b.
c.
Job number.
Current Date.
Date of next service.
6.
Leave working area clean and tidy.
7.
Dispose of spent filter/s in line with Environmental Policy disposal recommendations.
Page 86 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 42
PROCEDURE ~ LEGIONELLA RE-SAMPLING (MSRT8)
Sampling to be conducted from sites as required or notified by Legionella Duty Holder.
Sample collection
Cold water
1.
2.
3.
4.
5.
Hot water
1.
2.
3.
4.
5.
Flush tap to be sampled for 2 minutes.
Record water temperature.
Take the lid off a sterile sample bottle and place carefully to prevent
contamination.
Fill bottle to the neck and replace lid.
Keep bottle at room temperature and supply to the laboratory within 24 hours of
taking sample.
Flush tap to be sampled for 1 minute.
Record water temperature.
Take the lid off a sterile sample bottle and place carefully to prevent
contamination.
Fill bottle to the neck and replace lid.
Keep bottle at room temperature and supply to the laboratory within 24 hours of
taking sample.
Reporting
Legionella analysis takes up to 10 days for completion. However laboratories regularly inspect
the plates and interim reports are issued.
Where interim reports are issued it means there is Legionella present in the sample. The receipt
of such as result is forwarded immediately to the Legionella Duty Holder.
Report to show the following information:a)
Location
b)
Date of test
c)
Time of test
d)
System (Hot or Cold)
e)
Name of Operative
f)
Recommendations
The action required is determined by the Duty Holder, dependant on system operating
information, temperature at the time of testing and on the type of Legionella Species present.
Page 87 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 43
MAINTENANCE PERIODS FOR THE UNIVERSITY OF READING
Area
Description
Frequency
Risk assessment
Risk assessment of all sites for water
features likely to cause Legionellosis to
be conducted every 2 years or less
depending on the finding of the risk
assessment
2 years or as required
Schematics
Usually conducted during disinfection of
water system. Review to be carried out
during disinfection
2 years or as required
Chemical Disinfection
2 yearly disinfection of all water systems
with gravity feed cold water tank with
calorifier.
2 yearly or
dependant on risk
assessment
Domestic systems fed directly from
mains with small heaters will be
chlorinated by consultation with the risk
assessment
Tanks
>1000 litre internal inspection and
temperature check
<1000 litre internal inspection and
temperature check
6 month
Annual
Tanks (Drinking Quality)
Inspection and sample for TVC, Coliform, 6 month
and E.Coli
Calorifiers
Visual internal check with descaling as
necessary
Annual
Cleaned and disinfected
3 month
Flush outlet for 5 minutes (single point)
Record temperature at start and finish
Change as per manufacturers
recommendations – usually 6 monthly
Every Week
Showers
Little used outlets
Water Filters
Page 88 of 103 February 2016 review – Legionella Control – University of Reading
6 month
APPENDIX 43 (cont’d)
Area
Description
Frequency
POU
Water heaters
Test 3 monthly – check correct operation
temperature, adjust if required to maintain
at 50-60°C
3 monthly
Combination
Water Heaters
Inspect as CWST regime – Clean and
disinfect as necessary.
Annually
Water Softeners
Temperature monitor at one outlet
To ensure unit is operating satisfactorily
conduct hard/soft test weekly
Monthly
Weekly
Disinfect unit as per manufacturers
recommendations
Annually
Fogging and
Misting systems
If UV system fitted check for operation and
clean filters as per manufacturer’s
instructions
6 months
Automatically purge system when not
operational
Chlorination and sampling as per risk
assessment
Per risk assessment
Emergency
showers and eye
wash stations
Legionella
sampling
Flush for >5 minutes, with minimum of spray
on a periodic basis
3 months
As considered necessary or where indicated
by risk assessment , a single sample to be
collected from each hot and cold water
system
As necessary or as
indicated by risk
assessment
Bacterial quality
sampling
Sample to be collected from cold water tank/s or
drinking water outlets. Other systems as
required.
As necessary or as
indicated by risk
assessment
Page 89 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 44
GENERAL GUIDANCE - MAINTENANCE OF DIFFERENT PROPERTY TYPE
Area
Tenanted domestic
residences
Responsibilities
Water system controlled
by tenant
Multi occupancy
residences
Water system controlled
by tenant
Water system controlled
by E& F
Academic
Water system controlled
by E&F and all areas
accessible
Water systems
controlled by E&F but
local non fixed systems
by Departments
All other areas
Water system controlled
by E&F
Tasks to be carried out by
WQ-MTC Contractor
Minimum 2 yearly disinfection
and risk assessment review
WQ-MTC Contractor
Minimum 2 yearly disinfection
and 2 yearly risk assessment
review
WQ-MTC Contractor
Apply policy as all responsibility
with University of Reading
WQ-MTC Contractor
Apply policy as all responsibility
with University of Reading
Departments
Ensure risk assessments carried
out in local area and follow
University of Reading Policy
WQ-MTC Contractor
Apply policy as overall
responsibility with University of
Reading
WQ-MTC Contractor
Apply policy as overall
responsibility with University of
Reading
Page 90 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 45
SPECIFIC NON COMPLIANCE PROCEDURE
Water temperature
Non-compliance is assessed by the Legionella Duty Holder on a day to day basis and prioritised
and actioned accordingly.
Defect
Hot water temperature
above 70°C
Action
Raise Wren to reduce
temperature
(Priority 1)
Raise Wren to reduce
temperature (Priority 2)
Raise Wren to increase
temperature (Priority 2)
Determine reason for high
temperature
Action such as weekly
flushing, tank lagging, tank
volume reduction, pipework
lagging etc.. may be required
Period allowed
Immediate
1 Day
Defect
Cold water tank below
current guidance
requirements
Action
replace or refurbish
(WQ-MTC contract)
Period allowed
6 months
Calorifier drain not
operational for desludging
or sampling
Raise Wren to repair or
replace drain unit
(Priority 3)
1 month
Calorifier below current
guidance requirements
replace or refurbish
(WQ-MTC contract)
6 months
Hot water temperature
above 60°C
Hot water below 50°C
Cold water constantly
>20°C
1 week
1 week
2 months
Tanks and Calorifiers
Page 91 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 46
LEGIONELLA – ACTION LEVEL GUIDANCE
The notes below are just for guidance; interpretation of the results should be conducted by a
competent person or independent consultant.
Legionella testing is conducted on a regular basis around the site. Typically from a single
building one hot water and one cold water samples are collected as required.
The guidance on Legionella results should be considered with numbers of samples collected,
locations and system particulars at the time of the results.
Type of bacteria
Number of
bacteria
Action
Legionella
pneumophila
serogroup 1
>1000 cfu/l
(Hot or Cold)
System shut down
Disinfect Immediately
Up to 1000
cfu/l
Hot Water
Keep hot water at pasteurisation
temperature
Cold Water
Chemical disinfection of water
system
Any Legionella
Species other than
L. pneumophila
serogroup 1
>7,000 cfu/l
>1000 cfu/l
Shut down shower systems.
Hot Water
Keep hot water at pasteurisation
temperature
Cold Water
Chemical disinfection of water
system
Shut down shower systems.
Hot Water
Keep hot water at pasteurisation
temperature
Cold Water
Chemical disinfection of water
system
No of days for
action to be
completed
1 day or 24
hours
3 days or 72
hours
3 days or 72
hours
7 days or 168
hours
Shut down shower systems.
Up to 1000
Pasteurise hot water system and
14 days or
cfu/l
flush cold water to full system
336 hours
turnover
After completion of actions as indicated above, the system must be tested by sampling to ensure
that, the actions taken have resulted in a significant reduction of legionella levels.
Page 92 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 47
Health and Safety Services
Safety Note 43
The control of Legionella in departmental equipment
Scope
This Safety Note applies to the control of Legionella in items of equipment that are not
considered to be part of the building fabric and which are susceptible to colonisation by
Legionella. Such equipment would contain water which is held or recirculated at a
temperature between 20 – 45oC, and would not be maintained by Estates and Facilities (E
&F). In this context, the term “departmental” applies equally to Schools, Departments or
Units.
The control of Legionella in most areas of the University is described in the Control of Legionella
Bacteria Within Water Systems Policy and Procedures document (Ref. 1), which has been
produced by the Maintenance Services department of E&F. This policy applies to the water
systems which are considered to be part of the fabric of each building, and is designed to ensure
compliance with the Health and Safety Commission (HSC) Approved Code of Practice for the
control of Legionella bacteria in water systems, L8 (Ref. 2). The policy sets out the responsibility
for preventing or controlling the risks arising from systems that may be contaminated or
colonised by Legionella bacteria. The associated procedures do not refer in detail to items of
equipment which are owned, operated and maintained by Schools, Units or Departments. In
such cases, the responsibility for ensuring control of any risks that may arise from Legionella is
devolved to the relevant Heads of School or Unit Managers.
Responsibilities and Duties (See section 2 of the Control of Legionella Procedures document.)
Heads of Schools, Directorates, Departments and Units that possess equipment to which
this Safety Note applies are regarded as duty holders within the meaning of the Control of
Legionella Bacteria within Water Systems Policy & Procedures document. Their prime
responsibilities are to:
1. Ensure compliance with the requirements of the Approved Code of Practice, L8;
2. Ensure that departmental equipment is maintained to the standard necessary for the
control of Legionella.
3. Provide suitable and sufficient resources to enable compliance with the Policy
document in so far as it affects equipment under their control;
4. Keep records of departmental equipment servicing and maintenance;
5. Facilitate any monitoring or inspection work;
Page 93 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 47 (cont’d)
6. Ensure that no modifications/alterations or additions to water systems are carried
out, unless written approval is obtained from the E&F duty holder.
Where a School or Unit is responsible for the maintenance of individual items of equipment at
risk of colonisation, the School/ Unit is also responsible for minimising the likelihood that the
equipment may be colonised by Legionella, and ensuring that it does not present a risk of
infection when the equipment is used, maintained or repaired.
Hazard identification, risk assessment and control
The first priority is to identify all departmental equipment at risk of colonisation, and then
to assess the magnitude of the risk. The risk assessment must also identify those persons at
risk, for example because of their duties in respect of use, cleaning, adjustment or
maintenance of relevant items of equipment. Sampling for Legionella is not normally
required or recommended, unless the need is identified by the risk assessment.
Anyone who is allocated duties under this requirement must be given suitable
information, instruction and training to enable them to understand the nature of the risks,
and to undertake their duties in a safe manner.
Following the risk assessment, appropriate control measures must be put in place. In most
cases, this would be by the establishment of a suitable cleaning and/or maintenance
schedule, which may also involve the use of suitable biocides. The equipment manufacturer
should be consulted regarding “suitability” of any biocide being considered for use. Note
that the use of biocides will require a COSHH assessment before being undertaken.
The prevention and maintenance schedule must be operated in such a way that exposure
to any contaminated aerosols is either prevented, or (if prevention is not possible),
minimised. Note that exposure minimisation must not rely on the routine use of
respiratory protective equipment (R.P.E.): there are no items of R.P.E. that are certified to
provide protection against infection by airborne biological agents, as only one viable
organism/ contaminated droplet of water may be sufficient to cause infection.
The highest risk of colonisation or contamination of equipment will arise where water is
stored or recirculated in the critical temperature range of 20o – 45oC (peaking at 37oC),
but temperatures outside this range may also present a risk. Equipment producing sprays of
fine droplets of water will create the greatest risk of exposure.
Page 94 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 47 (cont’d)
Guidance:
Examples of such items of equipment include:
• Laboratory water baths;
• Water-jacketed incubators;
• Humidification equipment (however, most examples are covered under the
Legionella policy document);
• Items of equipment containing an integral water cooler or water purifier;
• Vending machines that are not permanently plumbed into the building water system, and
• Other equipment where stored water could be recirculated at room temperature and
where there is a potential for the dissemination of water droplets containing viable
Legionella bacteria.
Note that some equipment such as vending machines dispensing drinks may well be under a
maintenance contract from the manufacturer/ supplier. The terms of the contract should be
carefully studied to examine whether (for example) routine cleaning is included. See also the
E&F “Policies and Procedures” document, section 4.9.
Control procedures
Recommendations for specific items of departmental equipment are:
1. Laboratory water baths recirculating or storing water between 20 – 45oC
If possible, the water bath should be thermally disinfected on a monthly basis, by
increasing the temperature to >60o and maintaining the increased temperature for
30 minutes. After treatment, the water should be disposed of to drain without
splashing, and the bath thoroughly cleaned and descaled before being refilled with
deionised or distilled water. Using
deionised or distilled water will reduce the accumulation of limescale, which can
harbour biofilms / Legionella organisms. If thermal disinfection is not possible and
the volume of water contained is large, it may be impracticable to regularly drain
the water. In such cases, the use of a chemical biocide may be necessary – the
manufacturer of the water bath should be consulted to identify suitable chemicals
that are compatible with the equipment. In all cases, measures must be taken to
prevent splashing both during use and cleaning/ maintenance.
Page 95 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 47 (cont’d)
Case study:
Laboratory water baths operating in the critical temperature zone are liable to support a
thriving population of Legionella, and even baths operating at a lower temperature (<20oC) may
become contaminated, but the growth rate of the organisms is reduced. Baths regularly
operated at temperatures > 55oC are normally free of Legionella.
Normally, the risk of dissemination of contaminated water droplets is low, but if a stirrer or
recirculation Pump is fitted to the waterbath and the water level is allowed to drop to expose
the top of the stirrer paddles, then there is an increased risk of splashing and aerosol generation.
Older-style shaking waterbaths also present a risk of aerosol generation.
2. Water jacketed incubators
Water-jacketed incubators contain water which is normally held at the operating
temperature of the incubator. This is normally only ever drained if the incubator is
moved to a new position, or repair is required. The water contained within the
jacket may be in place for years, and may become heavily contaminated by biofilms
and Legionella, as the water within the jacket is normally static. During normal
operation, topping-up of the water jacket may be the only routine operation that is
undertaken. This operation presents a minimal risk of exposure to contaminated
aerosols, for example, when the filling-port is opened. By contrast, if the incubator
has to be moved, or the water-jacket drained down for repair, then there is a greater
potential for exposure to contaminated aerosols. This operation must be done in
such a way that splashing and generation of aerosols is minimised. A flexible hose
should be attached to the drain port, and the drainage water
directed into the waste pipe of a sink. Flushing deionised water through the water
jacket should minimise recolonisation. When the jacket is refilled to bring the
equipment back into use, deionised or distilled water should be used. Many such
incubators have a copper water jacket, which may in itself have an initial biocidal
action against Legionella and so minimise recolonisation.
Page 96 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 47 (cont’d)
3. Departmental water purification equipment
Most Departmental water purification equipment (such as water softeners - see
Section 4.10 of the Control of Legionella policy document) are permanently plumbed
into the water supply for the building. Such systems would normally be the
responsibility of E&F Maintenance, as they are considered to be part of the building
fabric. Departmental staff may however be involved in the routine regeneration of
resins in the equipment, and they must be made aware of the possibility that the
waste water arising during regeneration may be contaminated by Legionella. Disposal
of the waste water must be effected without splashing or aerosol generation.
Servicing or maintenance of such units is frequently under a maintenance contract
with the manufacturer of the equipment: the manufacturer’s recommendations
should be followed. The results of any water quality control checks required by the
equipment manufacturer must be recorded and returned to E&F Maintenance.
In some cases, specific items of equipment may be purchased with their own integral
water purification systems. Such systems must not be plumbed into the building
water supply without prior approval from E&F.
The manufacturer’s recommendations and instructions should be followed if
cleaning and routine maintenance is undertaken by Departmental staff. The results
of any quality checks must be recorded and returned to the E&F Legionella Duty
Holder.
Guidance:
Examples include units to provide ultra-pure water for analytical instruments in
laboratories, reverse osmosis units; hollow-fibre cartridge water purifiers etc.
However, note that biocidal action requires the presence of free Copper ions, usually at a
pH of 5.5 or less. Once water in the jacket has been in place for several weeks, the copper
will be covered in a thin oxide film, which will prevent any further dissociation of copper
ions into the water.
Normally, the ultra-pure or High Quality (HQ) water produced by the unit is not
liable to be contaminated: it is the “feed” side of the unit which may become
contaminated by the growth of a biofilm, especially if the water velocity through the
unit is low. In a cartridge unit for example, development of a biofilm would be
evident from the reduction in flow and increase in pressure required to generate a
given volume of ultra-pure water. The manufacturer’s instructions should be followed
for cartridge / membrane regeneration, but operators must be made aware of the
probability of Legionella contamination in the flush water. Splashing and aerosol
generation must be avoided when disposing of the effluent.
Page 97 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 47 (cont’d)
4. Items of susceptible equipment in University-owned buildings
There may be several types of equipment to which this description applies, and where
the equipment is the property of the building occupant (tenant). Unless the tenant
has an arrangement with E&F to undertake maintenance of the equipment, the
responsibility for ensuring that the equipment remains free from risk of colonisation
by or dissemination of Legionella remains with the building tenant.
5. Items of susceptible equipment that are the responsibility of E&F Maintenance and the
Water Quality Measured Term Contractors [WQ-MTC]
Equipment such as emergency drench showers and emergency spray heads in
laboratories are the responsibility of E& F Maintenance, who will arrange for risk
assessment and any associated control measures such as regular flushing (normally
undertaken by E&F Maintenance or by the WQ-MTC). IF Departmental staff are involved
in flushing of emergency showers/spray heads, the flushing operation must be
undertaken in such a way that creation of aerosols is avoided, and any potentially
contaminated water discharged to drain without splashing. A suitable system of work
should be identified by the risk assessment.
References
1
Control of Legionella Bacteria Within Water Systems – Policy and procedures document
issued by E&F
2
Legionnaires’ disease: The control of Legionella bacteria in water systems. Approved Code of
Practice and Guidance. Health and Safety Commission, ref. L8. HSE Books, 2000, ISBN 07176-1772-6
Page 98 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 48
PROCEDURE ~ WATER SOFTNER (DISINFECTION) (MSRT9)
1
Ensure compliance with COSHH assessment.
2
Agree the method of works with the client or client’s representative and complete any
required permits prior to any work being commenced.
3
Isolate/Close outlet valves from softener.
4
If necessary by-pass the equipment to sustain services. Ensure that hand isolating valves
are fully closed for the duration of the disinfection process.
5
Backwash the equipment thoroughly for 15 minutes.
6
Introduce a solution of NaOCL (Chlorine) at 0.3% - 0.5% with respect to available
chlorine, educted through the injection system.
Note! The quantity required will be approximately 2% by volume of available resin.
7
Monitor the effluent from the system at the drain point and record the level of chlorine.
8
Isolate the equipment and shut down for a period of 60 minutes
9
Thoroughly flush the system to remove excess chlorine and test at the drain to less than
0.5 p.p.m or the equivalent level provided by the water supplier.
10
Fully regenerate the system prior to reinstatement to service.
11
Certification is issued following disinfection, detailing the time and date of these works,
and identifying the specification used.
Page 99 of 103 February 2016 review – Legionella Control – University of Reading
APPENDIX 49
SAFE OCCUPATION OF NEW/REFURBISHED BUILDINGS AND SAFE SHUT DOWN OF WATER
SYSTEMS
This section identifies the control measures in place to mitigate against the risk from legionella
bacteria within the risk systems identified in the policy and where appropriate, design and
operational guidance for those undertaking new installations or refurbishment projects.
Operation of Systems - General
Occupation of New/Refurbished Buildings
Where new or refurbished buildings or parts of buildings are occupied, there is a risk of legionella
bacteria growing to high numbers within the water systems, particularly if there is a delay
between completion/handover of an area and its’ occupation.
Project managers and others responsible for the delivery of capital or refurbishment works shall
ensure that any water systems are cleaned and disinfected immediately before occupation &
suitable precautions measures to protect against contamination, e.g. regular recorded flushing, is
implemented during any commissioning or pre-occupancy period.
Where it is anticipated that there will be a delay in occupation of greater than one week, the
project manager or other responsible person shall notify the Legionella Duty Holder.
Arrangements should take into account the complexity of the system(s) concerned, any activity
or partial occupation of the area and any requirement for operation of the systems during the
delay period. Depending on the outcome of these discussions, options may include:
•
•
•
•
Implementation of the procedure for “Temporary Closure”
Implementation of the procedure for “Indefinite Closure”
A combination of the above, or other arrangements deemed appropriate to the risk.
Any arrangements implemented should be documented
Closure or vacation of buildings or parts of buildings
Where a building or part of a building is to be closed or vacated for a period of greater than one
week, the relevant Project Manager (Building Manager) must notify the Legionella Duty Holder to
discuss appropriate management arrangements to reduce the risk of legionella contamination.
In general, if the unoccupied period is anticipated to be less than 60 days, then the procedure for
“Temporary Closure” should be implemented.
If the closure is anticipated to be in excess of 60 days or is indeterminate, then the procedure for
“Indefinite Closure” should be implemented. Project managers should note that, where works are
involved in implementation, a recharge for these will be made.
Where the procedure for “Indefinite Closure” has been implemented, the following information
should be supplied at least one month to any re-occupation:
Page 100 of 103 February 2016 review – Legionella Control – University of Reading
•
•
•
•
Intended date of occupation
Any change in use of the building or area
Any areas which will not be used.
Any works undertaken on any of the risk systems within the building or area.
Note that before any water systems are returned to service following an “Indefinite Closure”,
modifications and/or maintenance will be required and the system will be chlorinated in
accordance with “Procedure MSPT1” Complete chlorination (Hot and Cold)
Safe Shutdown of Water Systems (Temporary Closure)
This procedure may only be used where systems, or parts of systems, are to be placed out of use
for a period of less than 60 days and MUST be used in conjunction with Procedure MSPT8 Flushing
unused outlets
Domestic Hot Water Systems
Pasteurise Calorifiers and the Hot Water Systems in full.
Switch off secondary circulating pumps, de-stratification pump (if fitted) and close calorifier feed
valve.
Isolate primary heat source(s) to calorifier(s) including immersion heater(s) if fitted
Identify suitable flushing points and set up a flushing regime. Initiate flushing regime until site is
to be reopened.
Cold Water Systems
Inspect CWS Storage tank, ensuring lids, screens, etc. are in place, overflow arrangements are
operational and clear of any obstruction and ball valve is operating correctly. Record tank
temperature.
Inspect any water pressure boosting system, ensuring that pressure switches are operating
correctly and auto pump changeover arrangements (if fitted) are operational.
Identify suitable flushing points and set up a flushing regime. Initiate flushing regime until site is
to be reopened.
Page 101 of 103 February 2016 review – Legionella Control – University of Reading
Safe Start Up of Water Systems (Temporary Closure)
Note: This procedure may only be used where a system, or part of a system, has been out of use
for maintenance purposes for less than 7 days, OR where a system, or part of a system, has been
out of use for up to 60 days AND a record of flushing of outlets is available for inspection. If a
record of flushing is NOT available, then Safe Start Up of Systems (Indefinite Closure) MUST be
followed.
Inspect system(s) and confirm operational status.
Domestic Hot Water Systems
Carry out Pasteurisation of Calorifiers/Hot Water Systems in full.
(Switch on secondary circulating pumps, de-stratification pump (if fitted) and open calorifier feed
valve.
Initiate primary heat source(s) to calorifier(s) including immersion heater(s) if fitted)
Cold Water Systems
Inspect CWS Storage tank, ensuring lids, screens, etc. are in place, overflow arrangements are
operational and clear and ball valve (fitted) is operating correctly. Record tank temperature.
Inspect any water pressure boosting system, ensuring that pressure switches are operating
correctly and auto pump changeover arrangements (if fitted) are operational.
Purge and flush water from all outlets on site. Record in logbook system.
System is ready for reoccupation
Safe Shutdown of Water Systems (Indefinite Closure)
Domestic Hot Water Systems only
Carry out Pasteurisation of Calorifiers/Hot Water Systems in full.
Switch off secondary circulating pumps, de-stratification pump (if fitted) and close calorifier feed
valve.
Isolate primary heat source(s) to calorifier(s) including immersion heater(s) if fitted)
Desludge calorifier via drain and allow system to cool.
System will remain charged and therefore ensure the Building is kept cold
Domestic Cold Water Systems
Clean and disinfect cold water tanks.
Isolate & label incoming water supply & water booster equipment (if fitted).
System will remain charged and therefore ensure the Building is kept cold
Page 102 of 103 February 2016 review – Legionella Control – University of Reading
Safe Start Up of Water Systems (Indefinite Closure)
Inspect system(s) and confirm operational status. If necessary refer to Facilities Team to confirm
procedure or for further advice.
Inspect CWS storage tank, ensuring lids, screens, etc.. are in place, overflow arrangements are
operational and clear and ball valve (if fitted) is operating correctly.
Carry out Chlorination of Water System including the mains water system. Chlorination should
be conducted with a 4 hour contact time.
Ensure that all parts of the system are filled and free of airlocks.
Inspect any water pressure boosting system, ensuring that pressure switches are operating
correctly and auto pump changeover arrangements (if fitted) are operational.
Reinstate secondary DHW circulation & de-stratification pumps (if fitted).
Reinstate primary heat source to calorifier including immersion heaters (if fitted). Ensure DHW
temperature control(s) are operational and set at 60 deg.C. .
When DHW calorifier temperature has reached 60 deg. C, allow one hour for temperatures to
stabilise and undertake standard monthly temperature checks.
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