Installer Guide Flexible plumbing by Wavin

Installer Guide Flexible plumbing by Wavin
Installer Guide
Flexible plumbing by Wavin
Next generation Hep2O
Unique ‘next generation’ benefits:
Easier installation and proven performance Approvals
Hep2O Polybutylene Pipe
Standard pipe
Barrier pipe
Cutting Hep2O pipe
Hep2O fittings
Jointing with Hep2O pipe and fittings
SmartSleeve™ pipe support sleeve
Jointing procedure
Jointing copper pipe to Hep2O fittings
Checking the joint using In4Sure™ joint
recognition technology
Demounting joints using the Hep2O HepKey™ system
Two types of HepKey™ are available:
To use HepKey Plus™:
To use HepKey™:
Hints and tips for trouble-free Hep2O installation
Hep2O pipe
Hep2O fittings
Handling and storage
Colour-coded packaging
Connecting Hep2O pipe to compression fittings
Hep2O connections adjacent to capillary joints
Connection to chrome plated or stainless steel pipe
Connection to brass spigots
Connection to earlier Hep2O systems
Connecting Hep2O fittings to other brands of pipe
Connecting Hep2O to steel pipes and
threaded bosses
Connections to appliances using Hep2O
System alterations
Using a blanking peg to seal off a fitting
Using a stop end to seal off a pipe
Where it’s OK to use Hep2O
Where it’s not OK to use Hep2O
Cabling through joists
Less risk to health and greater site safety
Hep2O push-fit jointing also has the
following advantages:
Other system benefits include:
Drilling the floor joists
Engineered joists
Spigot tees and manifolds Connecting pumps, valves etc:
Pipe support
Cable ties
Pipe support distances
Minimum bending radius for Hep2O pipe
Other jointing applications
33 34
Pipework installation
Concealed locations
Use of metal tape to aid ‘electronic’
pipe detection
Pipes through walls and floors
Laying pipe in floor screeds
Pipes adjacent to metalwork
Hep2O pipe means quieter operation
because there’s less noise…
Installing pipes in concrete floors or walls
Hep2O conduit system
Fitting a junction box
Fitting pipe into conduit
Terminating the conduit
Hep2O Pipe-in-Pipe system
Dry lined wall feeds for radiators
Radiator outlet cover plate
First-fix radiator feeds
Connecting Hep2O pipe to storage vessels
and radiators
Connecting Hep2O to ancillaries
(pumps, valves, etc.)
Connecting boilers and heaters
Installation and performance benefits
Hep2O within internal drywall systems
Hep2O within timber framed and steel
framed buildings
General advice
Freezing for maintenance/system modification
Painting Hep2O
Use of corrosion inhibitors
Electrical safety
Equipotential bonding
Woodworm / timber treatment
External installations
Pressure testing
Testing procedure
Portable buildings, site cabins, toilets etc.
Agriculture and horticulture
Typical Problems
1. Joint weeps
2. Split fittings
3. Pipe or fitting melting
General information
Advisory service
Other sources of information
Heating systems
Important information
Fault finding
This Installer Guide is designed to help professional plumbers
obtain the best results when using Hep2O plastic push-fit
fittings and pipe. It provides guidance on good plumbing
practice and comprehensive advice to enable users to get the best possible performance from the Hep2O system.
Hep2O is a fully tried and tested system and has been the
first choice of professional plumbers in the UK for over 30 years. We’ve listened to our customers, and made some
major improvements to the fittings. The result is our ‘Next
Generation’ Hep2O system.
Next Generation Hep2O
Next Generation Hep2O is our most technologically advanced
professional plastic push-fit plumbing system available, with a fully comprehensive range of white fittings and some
unique new features designed to reduce installation time and
improve operating performance.
Hep2O pipe is now white to match the new range of fittings,
but pipe flexibility and ease of ‘cabling’ is exactly the same as before.
The Hep2O system is available in 10, 15, 22 and 28mm sizes,
and we’ve introduced a simple colour-code for the packaging
to make identification easier:
• 10mm: green
• 15mm: blue
• 22mm: purple
• 28mm: orange
Fig. 1 Next Generation Hep2O
Unique Next Generation benefits:
We’ve listened to our customers, all professional plumbers
and heating engineers, and we’ve responded to their wish list
with some unique features that are not available with any other
comparable push-fit system:
Fig. 2 Cross section of Hep2O fitting
1. In4Sure™ joint recognition tells you when the pipe’s inserted
Just insert the pipe into the fitting then rotate it. If it’s fully
inserted you’ll feel a ‘rumbling’ sensation, caused by the profiled end of the pipe support sleeve making contact with the castellated seat inside the fitting.
2. New HepKey™ demounting system
The clever new HepKey™ makes demounting quick, easy and
tamper-proof, so joints only come apart when you want them to.
3. New SmartSleeve™ for reduced force joint assembly
As well as forming part of the new In4Sure™ technology,
the clever design of the new SmartSleeve™ pipe support sleeve
also reduces the force required to push the pipe into the fitting.
4. New white fittings with sleek new look
The white colour combined with a slimmer, more streamlined and altogether more stylish design, means Hep2O fittings are
now much more acceptable for ‘on view’ applications.
5. Same quality pipe – but now in white
We’ve changed the colour but all the other traditional benefits of Hep2O pipe have been retained. It is just as flexible as ever and
with our straight coil technology stays straight when uncoiled.
Market-leading 50 year guarantee
Due to a rigorous quality control and testing programme, all Next Generation Hep2O pipe and fittings are guaranteed for
50 years against defects in materials and manufacturing.
The only proviso is that good professional installation practice is
followed, as outlined in this guide. Notably, this includes working
within the peak life cycle operating temperatures and pressures
detailed in Table No.1 - see page 7.
Easier installation and proven performance
Hep2O has evolved over 30 years and is now recognised as the
professional’s system of choice. With significant performance
benefits, easier and quicker installations without any compromise on quality or joint integrity. Pipe flexibility and joint security remain the key benefits of Hep2O.
•Flexible pipe means it can more easily be ‘cabled’ around
•‘Cabling’ the pipe means fewer joints are required.
•Fewer joints reduce installation time and system costs.
•Push-fit also means no naked flames with reduced
inherent risks.
There are also significant long-term performance benefits over
traditional rigid metal systems.
• Plastic pipe means no scale build-up.
• No corrosion and reduced risk of burst pipes.
• Quieter in service, cooler to the touch and less heat loss.
Easy demounting with HepKey™
Easy cabling. Fewer joints
High resistance to impact
Measure and cut in-situ
No scale build-up
No bursts. Corrosion free
Fig. 3 Hep2O offers significant benefits over traditional systems
Hep2O carries a British Standard Kitemark against BS7291
parts 1 & 2 Class S. Standard pipe and fittings also carry a British Standard Kitemark against BS EN ISO 15876.
Barrier pipe and fittings also carry a British Standard Kitemark against BS EN ISO 21003.
All products are manufactured under the scope of a Quality Management System that is third party accredited to BS EN ISO 9001:2008.
BS 7291
Hep2O is listed in the Water Fittings and Materials Directory –
listing number 0812080.
Hep2O is suitable for use in domestic water distribution and
central heating systems including pressurised systems and
combination boilers in accordance with Table No. 1. It may
also be used in buildings other than dwellings providing the
service conditions are not exceeded.
Hep2O pipe is offered in two types, Standard and Barrier
(see page 9). Both are accepted by British Gas / Scottish Gas
Central Heating Care Contracts.
Table No. 1 Peak life cycle operating temperatures/pressures
20°C 30°C 40°C 50°C 60°C 70°C 80°C 95°C Short
at 114°C
Safe pressures:
11.5 11
160 152
10.5 9
Head of water (m) 120
110 105
All reference to Hep2O fittings on the following pages refer
to the latest ‘Next Generation’ range of all white fittings.
Hep2O Polybutylene pipe
Available in straight lengths or coils in Standard or Barrier.
Straight lengths of Hep2O Standard and Barrier pipe are
supplied in 3m lengths in 15mm, 22mm and 28mm diameters.
Straight pipe is just as flexible as coiled pipe and is primarily
intended for exposed pipework where neatness is vital, or where only a short length of pipe is required.
A unique characteristic of Hep2O pipe coil is its remarkable
ability to remain straight once uncoiled, unlike some other
plastic materials which act like a spring. This makes handling
so awkward that two men may well be required to carry out a relatively simple job.
Hep2O pipe is much easier to handle and much easier to
cable because of its inherent tendency to stay where it’s put. Even though the colour has changed from grey to white, the easy handling attributes of Hep2O pipe remain unchanged.
Coiled Hep2O pipe is supplied in 25m to 100m coils, in
10mm, 15mm, 22mm and 28mm diameters, in a SmartPack™
•Choice of Standard or Barrier pipe.
•Uncoiled pipe retains its flexibility.
•For installations into screed use the Hep2O ‘Pipe-in-Pipe’
system. This incorporates Hep2O Barrier pipe in a
pre-sheathed conduit.
Fig. 4 Hep2O pipe (left) comes off the coil straight
Standard pipe
•Suitable for domestic hot/cold water and heating
•When used for heating, a suitable inhibitor such as Sentinel
or Fernox MB1 should be used.
Barrier pipe
•Designed for central heating systems.
•Incorporates an oxygen barrier to inhibit oxygen permeation.
•Use of inhibitors are recommended as corrosion can occur
in all types of system regardless of pipe material.
•May also be used for domestic hot and cold water services.
Hep2O pipe is NOT suitable for conveying gas, oil or
underground supplies
• Cut length:
Standard and Barrier
straight cut lengths.
• Standard coiled pipe:
Straight coiled lengths in SmartPack™ dispenser.
• Barrier coiled pipe:
Straight coiled lengths in SmartPack™ dispenser.
• Pipe-in-Pipe system:
Hep2O Barrier pipe in blue or red conduit.
Fig. 5 Hep2O offers a range of pipe options
Cutting Hep2O pipe
Recommended cutters (HD74, HD75, HD77 or HD78),
as shown in the current Hep2O Trade Price List should be
used to cut Hep2O pipe. Place the pipe in the jaws of the
cutter and apply pressure, then rotate the pipe and maintain
the pressure until it is severed (see Fig. 6).
Before making a joint, check that the pipe end is clean, cut square and free from burrs and surface damage.
Do use recommended
cutters to cut the pipe.
Do test the pipe is fully
inserted into the fitting when making a joint using our In4Sure™ technology. Calculate
the correct pipe length, cut the pipe at one of the cutting marks ‘ ’ printed onto the
Fig. 6 Always use
pipe (see Fig. 8). The distance
recommended cutters
between the ‘ ’ marks is the
to cut Hep2O pipe
insertion depth into the fitting and this should be allowed for.
Don’t use a hacksaw to
cut Hep2O pipe.
Don’t use damaged pipe.
Ensure pipe ends are free from burrs and surface
damage. If not, re-cut the pipe.
Fig. 7 Don’t use a hacksaw
to cut Hep2O pipe
Table No. 2 Correct insertion depths for Hep2O fittings
Pipe size
Nominal insertion depth including sleeve
SmartSleeve™ support sleeve is an integral part of
the system and should NEVER be omitted when
using Hep2O pipe.
Fig. 8 Hep2O 15mm assembly with pipe markings
Hep2O fittings
Hep2O fittings are only available in white. They are offered in
colour-coded packs (see ‘Packaging’, page 20) in a range of
sizes 10, 15, 22 and 28mm and in a comprehensive range
of types to answer all domestic hot/cold water and heating
All O-ring seals contained in Hep2O fittings have been
pre-lubricated during factory assembly and during normal
installation additional lubrication should not be required.
If the fitting has been used previously then the lubricant may
have been removed and may require replacing. In these
situations Hep2O Jointing Lubricant Spray (code HX200) must
be used to avoid contravention of Water By-laws and ensure
compatibility with other system materials (see Fig. 9).
Don’t use other manufacturer's lubricant or any alternative.
Fig. 9 Spraying used O-ring with silicone lubricant
Jointing with Hep2O pipe and fittings
SmartSleeve™ pipe support sleeve
Before making a joint using Hep2O pipe, it is essential to insert
a Hep2O SmartSleeve™ pipe support sleeve into the cut pipe
end (see Fig. 10). The only exception is when connecting to the
open spigot end of a Hep2O fitting.
The SmartSleeve™ has several purposes:
•It ensures the pipe retains its circular cross-section.
•It eases insertion of the pipe into the fitting.
•The profiled end of the SmartSleeve™ helps you to check
the pipe is fully inserted. See In4Sure™ joint recognition
technology (see page 15).
•It maintains the rigidity of the pipe within the fitting.
•It retains the circular cross-section of the pipe under extreme
•Barbs on the SmartSleeve™ lock it in the pipe, which helps
ensure it is not left in the fitting when demounting. All SmartSleeve™ pipe inserts are manufactured from ‘food
quality’ 316 stainless steel and are impervious to contaminants.
They are designed to be captive in the pipe but can be removed
if required, using long nosed pliers. However, if damaged, the
SmartSleeve™ must not be re-used.
Fig. 10 Inserting SmartSleeve™ into pipe
Jointing procedure
Whichever type of Hep2O fitting is used, the same jointing
procedure should be followed.
1. Cut the pipe squarely
at one of the ‘ ’ marks
using recommended pipe
cutters and ensure the
pipe end is free from burrs (see page 10).
2. Insert a Hep2O
SmartSleeve™ pipe
support sleeve into the pipe end.
3. Push the pipe firmly
into the fitting, then
use Hep2O’s unique
In4Sure™ joint recognition
technology to ‘feel’ if the
pipe is fully inserted
(see page 15).
4. Tug back on the pipe to
ensure the grab-ring engages correctly and prevents the pipe withdrawing.
Fig. 11 Hep2O jointing sequence
Jointing copper pipe to Hep2O fittings
Hep2O fittings have been designed to form reliable joints with
metric copper pipe which conforms to BS EN 1057 - R520.
1.Measure the pipe, allowing sufficient length for insertion
into the fitting, and mark with a pencil (see Table No.2).
2.Cut the copper pipe with a wheel cutter.
3.Carefully inspect the pipe ends for burrs or swarf.
4.Push the pipe firmly into the fitting.
5.Tug back on the pipe to ensure the grab-ring engages
correctly and prevents the pipe withdrawing.
Fig. 12 Hep2O fittings
are also compatible
with copper pipe
Fig. 13 HX3A/22 3/4"
Imperial/22mm adaptor
With a little extra care, it is also possible to connect 10mm BS EN 1057 - R220 copper pipe into Hep2O fittings.
R220 pipe is particularly ‘soft’ and therefore susceptible to
becoming misshaped or dented if it is not handled with care.
Particular attention should be paid to the cut end, looking for
any signs of damage. R220 copper pipe should be cut with a
mini wheel cutter, and then a chamfer should be filed on the
pipe and any copper filings rinsed away, and the pipe dried-off.
Hep2O can also be connected to ¾" Imperial copper pipe using
a special O-ring straight adaptor (HX3A/22) which accepts
22mm copper pipe at one end and ¾" Imperial copper pipe at
the other.
New pipe insert for copper providing joint recognition will
be available soon.
Checking the joint using In4Sure™ joint
recognition technology
Follow normal procedure to establish the insertion depth of
the pipe into the fitting as previously described (see page 13).
In4Sure™ joint recognition technology then provides a further
check by allowing you to ‘feel’ if the pipe is fully inserted.
Fig. 14 Cut-away showing In4Sure™
joint recognition technology
To use In4Sure™ joint recognition technology:
1.Hold the centre (fixed) part of the fitting in one hand.
2.After inserting the appropriate pipe sleeve, push the pipe
firmly into the fitting.
3. While still pushing, rotate the pipe using a screwing
action. If the pipe is fully inserted you will feel a ‘rumbling’
sensation as the profiled end of the SmartSleeve™ passes
over the castellated seat inside the fitting.
4.Pull back to check the joint integrity.
This simple procedure is designed to give you the peace of
mind that comes from knowing that the joint is good. You can
also make a visual check by checking the next ‘ ’ mark is
level with the end of the fitting.
Demounting joints using the Hep2O
HepKey™ system
Two types of HepKey™ are available:
•HepKey Plus™ simply clips onto the fitting and holds the
grab-ring in its release position.
•The HepKey™ is small enough to be kept in your pocket.
Fig. 15 HepKey Plus™
Fig. 16 HepKey™
Both types are colour-coded: 10 green, 15 blue, 22 purple
and 28mm orange.
Whichever type of Hep2O fitting is used, the same demounting
procedure should be followed.
Fig. 17 Cut-away drawing of HepKey Plus™
To use HepKey Plus™:
1. Place the HepKey Plus™ around the pipe
2.Clip HepKey Plus™ over the fitting
3. In this position it depresses the inner release
ring of the fitting.
4. Withdraw the pipe from the fitting.
Step 1
Step 2
Step 3
Step 4
Fig. 18 Demounting sequence using HepKey Plus™
Fig. 19 Cut-away drawing of HepKey™
To use HepKey™:
1.Clip the HepKey™ round the pipe next to the joint to
be demounted, with the flat side of the HepKey™ away
from the fitting.
2.Slide the HepKey™ up to the fitting and press so that the
protruding 'lugs' depress the inner release ring of the fitting.
3.Withdraw the pipe from the fitting.
Before re-using the fitting we recommend applying a small
amount of Jointing Lubricant Spray (code HX200) to the
O-ring seal inside the fitting (see page 11).
Hints and tips for trouble-free
Hep2O installation
These are simple and effective precautionary steps which
should be taken to avoid problems and ensure trouble free
installation of Hep2O.
Hep2O pipe
The biggest potential problem is damage to a pipe end, in the form of a deep scratch which can create a leak pathway
for water to pass. Taking a few precautionary measures can
eradicate any such problems.
•Take care how and where the pipe is stored.
•Retain pipe in protective packaging until it is to be used.
•Never use an open bladed knife to remove the
pipe packaging.
•In the case of coiled pipe, always use the shielded blade tool
supplied (see Fig. 20) to slit the packaging around the inside
of the coil. This enables the pipe to be drawn from the inside.
The packaging then serves to contain the coiled pipe until
the last metre (see Fig. 21).
•When threading pipe through holes in stone, brick or block
walls always use a pipe sleeve or a small piece of foam pipe
insulation to protect the pipe from the rough surface.
•Ensure exposed first fix pipe ends are protected from
damage by using a temporary end protector. This also
ensures no debris will enter the pipe (see Fig. 22).
•Avoid kinking the pipe during installation.
Fig. 20 Unwrapping coil
Fig. 22 Always protect
pipe ends
Fig. 21 Packaging retains
pipe until last metre
Hep2O fittings
As the fitting cannot be taken apart few problems can arise
but some basic precautions are advisable.
•Avoid dust and debris entering the fitting.
•Store materials in a secure place free from dust and dirt etc.
•Keep fittings in their bags until ready for use.
•When re-using a fitting, spray a little Hep2O HX200 Jointing
Lubricant onto the O-ring (see Fig. 9 on page 11).
Handling and storage
Hep2O is an extremely tough and durable system.
However, following the simple guidelines below will ensure its performance is not impaired by poor storage.
•Straight lengths of Hep2O pipe should be stored flat or
stacked vertically.
•Coils may be laid on their side or edge.
•Pipe and fittings, wherever possible, should be stored in their
original packaging. This ensures protection from ultra violet
light and reduces the risk of contamination.
•All Hep2O pipe and fittings should be protected from contact
with petroleum and oil derivatives.
•Avoid dragging the pipe along the ground or on other
surfaces such as walls.
•When feeding pipe through holes in walls and brickwork pipe
ends should be taped over, or an end cap should be used.
These precautions will protect the pipe end from damage
and also prevent debris entering the pipe.
•Care should be taken to avoid kinking the pipe
during installation.
Colour-coded packaging
To make buying, handling, storing and installing the Hep2O
system as simple as possible, a colour-coded system has
been introduced.
Hep2O fittings are now supplied in sealed polythene bags
colour-coded by size, which makes them easy to keep clean
and easier to identify – you can see all the 15mm fittings at a
glance – just look for the blue packs.
Just to make it easier still, the same colour-coded packaging
has also been applied to Hep2O pipe.
• 10mm: green
• 15mm: blue
• 22mm: purple
• 28mm: orange
No more searching the van to find those elusive 22mm
elbows, just look for the purple bag!
Fig. 23 Colour-coded packaging is designed to make
product selection easier
Other Jointing Applications
Connecting Hep2O pipe to compression fittings
Hep2O pipe is suitable for connecting to compression fittings
which comply with BS EN 1254.
Cut the Hep2O pipe with the recommended cutters and
proceed as follows:
1.Cut pipe and insert a Hep2O SmartSleeve™ pipe support
sleeve into the pipe end.
2.Apply PTFE tape if required.
3.Fully insert the pipe into the fitting.
4.Tighten nut, taking care not to over-tighten.
Insert support sleeve into pipe
Apply PTFE tape if required
Ensure pipe is fully inserted
Tighten nut
Fig. 24 Procedure for connecting Hep2O pipe to a
compression fitting
•Do not use oil based jointing compounds
•Always use an appropriate SmartSleeve™ pipe
support sleeve
•Use copper olives in preference to brass
•Hep2O pipe will not rotate in a compression
fitting after tightening
Other Jointing Applications
Hep2O connections adjacent to capillary joints
When using Hep2O pipe or fittings adjacent to capillary joints,
soldering work should be carried out before the Hep2O
is installed. If this is not possible, keep any heat away from Hep2O and observe the following precautions:
1.Don’t allow Flux to run onto Hep2O pipe or fittings. Flux runs
inside the pipe may occur during soldering, this effect can
be reduced by not using excessive amounts of Flux and by
applying Flux to copper pipe end only.
2.Don’t allow hot solder to come into contact with Hep2O.
3.Don’t allow Hep2O to overheat. Wrap a damp cloth around
copper pipe to minimise any likely heat transfer or use a heat absorbing gel.
Systems should be flushed with water to remove any
internal Flux residues.
Connection to chrome plated or stainless
steel pipe
Hep2O fittings cannot be connected directly to chrome plated
copper or stainless steel, because of the relative surface
hardness of these materials. The recommended method is to
use compression fitting (see page 21).
Connection to brass spigots
The only brass spigots suitable for jointing into Hep2O fittings
are those included within the Hep2O range. Brass spigots
designed for compression or capillary joints do not have the
necessary joint grooves and are too short.
Connection to earlier Hep2O systems
Hep2O is fully compatible with all current and earlier versions
of Hep2O fittings, including its immediate predecessor and the
earlier Acorn® system manufactured by Bartol.
Pre-1984 Acorn® 22mm pipe was manufactured with a
thicker wall and requires a different pipe support sleeve. If carrying out remedial work on such a system please contact our Technical Advisory Service – Tel: 0844 856 5165.
Other Jointing Applications
Connecting Hep2O fittings to other brands
of pipe
Hep2O fittings should not be used in conjunction with other
manufacturers’ plastic pipe and fittings, as dimensional
tolerances and quality control cannot be guaranteed by Wavin.
Connecting Hep2O to steel pipes and
threaded bosses
In order to facilitate connection to male and female iron threads,
four adaptors (HX28/HX29 socket adaptors) and (HX31/HX30
spigot adaptors) are available in the Hep2O range. This enables
connection to a wide range of different materials.
HX28 Socket adaptor
HX29 Socket adaptor
HX30 Spigot adaptor
HX31 Spigot adaptor
Fig. 24 Hep2O adaptors
Other Jointing Applications
Connections to appliances using Hep2O
When connecting to appliances and dishwashers always use
Hep2O appliance valves from the Hep2O range (HX38/15).
Adjacent Hep2O pipework should be clipped in accordance
with the recommended clipping distances using screw-type
clips (HX85) (see pipe support - page 29).
HX30 Spigot adaptor
Fig. 25 Valves for connecting appliances
System alterations
Using a Blanking peg to seal off a fitting
When you need to provide a temporary or permanent seal
to one of the ports on a Hep2O fitting, insert a blanking
plug (HX44) directly into the open connection. You can use
In4Sure™ joint recognition technology to check the plug is
fully inserted. To remove the plug use a HepKey™ or HepKey
Plus™ and continue with the installation.
Fig. 26 Blanking peg shown on its own, and inserted into fitting
Using a stop end to seal off a pipe
When you need to close off the open end of a pipe, first fit a SmartSleeve™ support sleeve in to the open pipe
end then fit a stop end (HX62) onto the pipe to provide
a temporary or permanent seal.
Fig. 27 15mm stop end
Other Jointing Applications
Where it’s OK to use Hep2O
Hep2O is suitable for most domestic and commercial
hot/cold water and heating applications. A comprehensive
range of fittings meets all today’s requirements and provides
secure connection and reliable operation. Providing installation
work has been carried out using good plumbing practice
as outlined in this guide, all Hep2O pipe and fittings are
guaranteed for 50 years under normal use.
Fig. 28 New Hep2O is now more compatible with modern
sanitary ware
Where it’s not OK to use Hep2O
The Hep2O system has been designed and tested to meet
the requirements of modern heating and water distribution
Testing has not been carried out to determine suitability for
other purposes and therefore Hep2O should not be used in
the following applications:
•Conveyance of gas
•Conveyance of fuel oil
•In areas contaminated by petroleum and oil derivatives
•Conveyance of compressed air
•Hep2O is not suitable for use in systems where the water
carried in the pipe contains a high concentration of chlorine
e.g. swimming pools or decorative water features
•Hep2O will not be affected by those levels of chlorine
expected in the UK water supply (typically less than 0.5ppm).
Short term chlorination for disinfection will not have an
adverse effect on the system (see page 51).
•Hep2O should not be used for the primary circuit of a
Solar Heating System as temperature cannot be
thermostatically controlled. Hep2O is suitable for secondary
circulation of these systems. • Hep2O should be protected at all times from exposure
to direct sunlight and ultra violet light.
•Hep2O should not be installed in Continuously operated
re-circulating systems (Secondary Hot Water Circulation
/ Ring main installations). Please see Important
Information section on page 51 for more details.
Cabling through joists
The Building Regulations Approved Document A allows for
pipework to be installed in joists by either notching or drilling.
The traditional method has been to notch the joists as the
rigidity of the pipe does not easily allow for any other method
of installation. However this has a number of disadvantages:
•Pipework must be installed prior to the floorboards
being laid.
•Plumber has to work on open joists increasing risk
of accident.
•Need to return after floors are laid to connect radiators, etc.
•Tails often moved by other tradesmen, causing extra work to
reposition pipework correctly for radiators.
Fig. 29 Hep2O speeds up installations because pipework
can be easily cabled through drilled joists
The exceptional flexibility of Hep2O pipe removes most of
these restrictions by allowing pipe to be easily curved and
‘cabled’ through drilled joists, or I-beams which means:
•Flooring can be laid prior to the plumber carcassing
from below which will progress the building schedule as other trades can work on the floor above e.g. to form
studwork etc.
•Site safety enhanced as the plumber is not exposed to the
danger of falling or the discomfort of kneeling on open joists.
•Other trades working below are protected from the dangers
of falling tools, molten solder, gas bottles etc.
•Carcassing at a later stage in the construction programme
means the building is likely to be weatherproof.
•Less danger of puncturing the pipe with nails used for fixing
the floorboards and no need to use protective devices such
as ‘joist clips’.
It is worth noting that drilled holes in joists should be large
enough to allow for thermal movement of the pipe.
Less risk to health and greater site safety
The unique Hep2O system ensures:
• Effective, leak-free pipe jointing without the
use of a naked flame.
•No soldering means safety from fire, especially
in restricted spaces.
•Improved working environment.
•No Flux or Solder eliminates potential contamination
of water supplies.
Hep2O push-fit jointing also has the following advantages:
•No naked flame means that precautions such as obtaining
a ‘Hot Work’ permit, having a fire extinguisher readily
available, and remaining on site for a while after jointing, are not necessary.
•No risk of infringement of Health and Safety
recommendations applicable to some brands of Flux. e.g. means to control exposure to noxious fumes when
working in a confined space, and use of eye protection
(where appropriate).
•After jointing, the fitting is clean and safe to touch, e.g.
after soldering, the joint is hot and Flux traces need to be removed.
•Joint is rotatable after installation.
Other system benefits include:
•Longer pipe runs and less joints, due to pipe flexibility.
•Elimination of ‘dry runs’ as pipe can be cut and jointed
in situ.
•Absence of solvents means testing can be carried out as
soon as installation is complete.
•Tails for connection to sanitary ware can be left long enough
for final connection, thus eliminating the need for straight
and offset connectors as with rigid pipe systems.
•Natural flexibility of the pipe helps overcome small
Drilling the floor joists
•Hole diameters should be no greater than 0.25 of the depth
of the joist and should be drilled at the neutral axis.
•They should be not less than 3 diameters (centre to centre)
apart and should be located between 0.25 and 0.4 times the
span from the support.
The Building Regulations Approved Document A gives
exact instructions on the drilling of floor joists.
These points are illustrated (see Fig. 30).
The value 0.25 is obviously one quarter and can easily be
calculated on site. The value 0.4 is less obvious and can be
obtained (see Fig. 31).
0.4 x ‘S’
0.25 x ‘S’
Fig. 30 Explanation of drilling joists in accordance with the
Building Regulations Approved Document A
The minimum distance between a hole and a notch in the
same joist should not be less than 100mm.
Distance from Support (m)
m Su
e fro
um D
e fr
Span of joist (m)
Fig. 31 Graph showing dimension of joist drilling zone from support
This graph should be used in conjunction with Fig. 30.
Example of use: Joist span is 4.5m.
Find value on horizontal scale and read up to sloping line.
Transfer point of intersection to the vertical scale and
read 1.8m.
Engineered joists
Hep2O is ideal in buildings incorporating timber ‘I’ joists.
Piping can be properly installed through holes in the web
section without damaging flange members (eg. TJI Joist
system, Truss Joist MacMillan Ltd.) even where the preformed holes do not align on the plan.
Spigot tees and manifolds
The Hep2O system incorporates a comprehensive range of
spigot tees which can be used individually or in groups to
give manifold arrangements with the benefit of 360° rotation.
Alternatively, the system includes a selection of manifolds
from single to four ports (see page 47).
Connecting pumps, valves etc:
Where Hep2O is connected to pumps, valves and similar
devices consideration should be given to adequately
supporting the item in question (bearing in mind the rotatability
of the Hep2O joint). Equipment should not be suspended from
the pipe without adequate support.
Pipe support
The Hep2O system includes two types of pipe clip - the screw
fix type (HX85) and the nail type (HX65).
Nominal Diameter
Nominal Diameter
Nominal Diameter
The HX86/22 spacer can be
used with both the HX85/22
and HX85/28 clip.
Fig. 32 Pipe clips
The nail type is designed for use on concealed pipework for
rapid fixing to timber. The screw type may be used together
with a spacer (HX86) to allow greater spacing between the
pipe and the fixing background. The spacer therefore allows
different pipe fixing centres which can be used to facilitate
pipe cross-overs or fitting of thermal insulation to the pipe.
Pipe Clip
Pipe Clip and Spacer
Fixing hole size is 5mm diameter.
Nominal Diameter
Dimension A
Dimension B
Fig. 33 Pipe fixing centres
A cold forming bend fixture (HX75) is also available to allow
the formation of a bend on 15mm and 22mm pipes for
situations where secure fixing and neatness are important.
Fixing hole size is 5mm.
Suitable for a No. 10 woodscrew
Nominal Diameter mm
Radius A mm
Fig. 34 Cold forming bend fixture radii
Cable ties
When pipe is concealed, cable ties may be used for support
instead of clips. However these should not be over-tightened.
The pipe should be allowed to slide freely to allow for thermal movement.
Pipe support distances
The recommended support distances for general purpose use are shown in Table No. 3.
Where piping is adequately supported or is run within
concealed spaces (e.g. through suspended timber floors)
clips can be reduced or omitted provided that:
•Pipe does not form part of an open vent provided for safe
operation of a heat source.
•Pipe does not form a distribution pipe or circuit where
effective air venting might be impaired by poor pipe
•Hot pipe will not come into contact with cold pipe
or vice versa.
•There is no risk that pipes or fittings will come in contact
with sharp, abrasive or other potentially damaging surfaces.
•There is no risk pipe will come in contact with materials
which may be affected by transmitted heat.
Where pipe is visible, a support distance between fixings of 300mm is suggested.
Where provision has been made for electrical wiring, such as in some partition systems, this can often be utilised for Hep2O pipework.
Table No. 3 Recommended clipping distances
Nominal Diameter
Horizontal Runs
Vertical Runs
Minimum bending radius for Hep2O pipe
Nominal Diameter
Fig. 35 Minimum bending radii (8x pipe diameter)
Fig. 34 shows a cold formed bend fixture (HX75). This is
suitable for use with 15mm or 22mm where secure fixing and neatness are important.
Hep2O pipe can easily be manipulated by hand to form bends
of any angle. In order to prevent any long term detrimental
effect on the material, the curvature of Hep2O pipe should
be not less than that shown. A bending radius of 8x the pipe
diameter is the minimum allowed.
Pipework installation
Hep2O fittings are now much sleeker and more stylish than
previously, making them a lot more acceptable for exposed
However, Hep2O pipe expands as temperature increases,
causing it to undulate along its length and this effect is
sometimes exacerbated where it is ‘cabled’ through joists.
This will not create airlocks or have any other adverse effect
on the operation of the plumbed system.
Concealed locations
Hep2O pipe is relatively easy to install in concealed locations
in floors, roof spaces etc. Any expansion in the pipe will have
little mechanical effect, this being absorbed within the pipe
length so undulation can be ignored.
Installation in difficult locations is aided by the cabling
ability of Hep2O pipe. If adequately supported, Hep2O pipe
in concealed locations need only be clipped for system
alignment e.g. at changes in direction. If preferred, cable ties
can be used in such areas.
Use of metal tape to aid ‘electronic’ pipe detection
The NHBC Standards includes a section which affects the
installation of pipework in walls. It states:
‘Where pipework is in or behind wall surfaces, and would
otherwise not be detected by a metal detector or similar
equipment, a metallic tape should be applied to the pipework’.
The NHBC has agreed that other methods of installing tape
are also acceptable, as any tape applied to plastic pipe or
fittings will require testing to ensure compatibility with the pipe
and ensure the adhesive will not pass through the pipe and
taint the water.
Metallic tape with an adhesive backing should NOT
be applied directly to Hep2O pipe and fittings, but the
following methods of aiding detection are allowed:
Metallic tape without adhesive can be lightly crimped around
the pipe to allow detection by an electronic pipe detector or,
adhesive metallic tape can be stuck to the backing wall as
close as possible to the pipe run.
Fig. 36 Metallic tape can be used to aid electronic
pipe detection
Pipes through walls and floors
Wherever Hep2O pipe passes through brickwork, stone or
concrete it should be sleeved. The annular gap between the
pipe and the sleeve should be filled with a resilient material to
provide an effective fire stop and also prevent the transmission
of noise from one room to another.
Expanding foam, in its initial wet state, must not come into
contact with the Hep2O pipe as it can cause an adverse
chemical reaction whilst drying. The use of a pipe sleeve will provide the necessary protection.
Laying pipe in floor screeds
Unlike metal pipes, Hep2O is not affected by the corrosive
effects of cement, lime, mortar or concrete. However,
account should be taken of the Water Byelaws which requires
distribution pipework to be accessible to facilitate its removal
and replacement (see page 35 Hep2O Conduit system).
Pipes adjacent to metalwork
When running Hep2O adjacent to or ‘through’ metalwork, it is
important to ensure that the pipe doesn’t come into contact
with any sharp edges as any subsequent thermal movement
could cause damage.
The following cautionary measures should be observed:
•Where pipe passes through a small drilled hole, fit a
suitable grommet •Where pipe passes through a large hole in metalwork
or adjacent to a sharp edge, fix an extruded flexible profile to the metalwork
•Provide adequate pipe clips or cable ties to prevent
abrasive contact between pipe and metalwork
•Run the pipe within a conduit
Hep2O pipe means quieter operation because there’s
less noise…
Problems with noise are often found in systems which
incorporate rigid pipes. Hep2O pipe does not transmit
noise and with careful installation, can be installed to run almost silently.
…from friction
Noise can be caused by friction between a pipe and adjacent
surfaces – typically where rigid pipes are installed beneath
timber or chipboard flooring.
Hep2O can greatly reduce this effect. Where holes are drilled
through joists they should be of sufficient diameter to allow
Hep2O pipe to slide freely (see page 26). This will prevent any
friction between the underside of a floor, and more importantly,
it will avoid the ‘ticking’ and creaking normally associated with
the thermal movement of rigid pipes
…from knocking
Noise can be caused by rigid pipes knocking together or
knocking on adjacent surfaces. Hep2O’s inherent elasticity
cushions such impact, causing less impact noise and
absorbing vibration, thus preventing the transmission of sound along the pipe.
…and from ‘water hammer’
Similarly noise from ‘water hammer’ resulting from abrupt
stoppage of water flow (typically by closure of quarter turn
valves, solenoids and reverberating ball valves). Such noise
is normally absorbed by Hep2O and is not transmitted along
the pipes.
Installing pipes in concrete floors or walls
Hep2O Conduit system
The Hep2O Conduit system allows pipe and fittings to be
installed directly into concrete floors or into walls whilst
complying with the requirements of the Water Regulations.
The flexible conduit allows Hep2O pipe to be easily
withdrawn for inspection, and junction boxes allow maximum
accessibility to fittings for inspection and possible removal.
If any bent sections of conduit pipe are formed in an
installation then future replacement of the Hep2O is likely
to require the use of a ‘draw cable’. This requires a cable to
be attached to one end of the Hep2O pipe before it is pulled
out of the conduit from the other end. The draw cable remains
in the conduit. Subsequent replacement of a new section of
Hep2O pipe may require two operatives; one pulling the draw
cable which is attached to the pipe end, and the other person
feeding-in the new length from the opposite end. Future
replacement will be easier if conduit bends are kept to a
minimum and any radius kept as large as practicable. See also ‘Fitting the conduit’, later in this section.
The system is available in all diameters, together with junction
boxes with lids and terminal fittings.
Holes can be cut in the sides of the junction box at the
appropriate position to accommodate the conduit which
simply clicks into position.
The Hep2O pipe should be fed into position at the same time
as the conduit system is installed, i.e. before screeding. The conduit system should not be installed on sub-floors
a long time in advance of screeding as damage by site
traffic could occur. The junction box allows access to pipe
fittings, and also allows pipe cross-overs (which are normally
undesirable within the floor screed material).
Dimensions are shown (see Fig. 39).
Fig. 37 Conduit junction box
Fig. 38 Cut conduit box for
wall termination
The conduit pipe should be fixed to the sub-floor using
suitable straps to prevent movement. Conduit pipes for
cold water systems should not be run in floor screeds which
incorporate underfloor heating loops. If required the junction
box can be cut in half and installed up against a wall (see Fig. 40).
Fig. 39 Junction box dimensions
Installation continued
Hep2O pipe to
radiator or sanitary appliance
Junction box lid
Hep2O elbow
Junction box cut in
half and secured to
sub floor
Fig. 40 Cut junction box
The junction box should be drilled using a hole cutter or spade bit, to allow the conduit to fit snugly and click into position. It should protrude at least 5mm inside the box. Hole sizes and conduit OD’s are shown in Table No. 4.
Table No. 4 Drill size for conduit box holes
Hep2O Size
10 & 15
Conduit Code
OD (mm)
HXC25/15 - HXC50/15 - HXXC50/10 - HXXC50/15
HXC25/22 - HXC50/22 - HXXC50/22
Central heating pipework should not be run within the
same junction box as cold water pipework unless there
is space to fix adequate thermal insulation to prevent the
warming of the cold water. The prevention of cold water
becoming warm is a Water Regulations requirement.
Fitting a junction box
The junction box should be fixed to the sub-floor to prevent
movement during screeding. Fixings with suitable washers
should be used and the box should be positioned so that the
lid (when fitted) will be level with the adjacent final floor finish.
If the required screed depth exceeds that of the junction box,
suitable packing should be placed under the base.
However, if the junction box is to be installed into insulation,
there is no effective method of holding the box down, so double sided adhesive tape should be used.
Junction box lid,
drilled and secured
by fixing screws
Junction box
secured to the
Small insulating pad,
cut and placed to
separate pipes at
Tee on cold
water pipe
Thermal insulation barrier
formed across junction
box (if necessary).
Tee on hot
water pipe
Fig. 41 Hot and cold water distribution pipes at tees
Thermal pipe insulation is not necessary when the junction
box is used solely for central heating pipes.
Fitting pipe into conduit
To facilitate the possible removal and replacement of Hep2O,
the conduit should be installed without joints and should
ideally run in straight lines between junction boxes. Where
bends are unavoidable, there should not be more than two
changes of direction between adjacent junction boxes.
•Conduit carrying cold water pipes should not touch conduit
carrying hot water or central heating pipes.
•When running conduit within floor screeds the recommended
gap between hot and cold should not be less than 50mm in order to prevent the warming of cold water (see Fig. 42).
•The conduit system should not contain unused water pipes
which remain connected to water systems. Redundant
pipework will result in water stagnation which would pose a
risk to health.
Conduit for cold water pipe
Conduit for hot water or central heating pipe
Fig. 42 Spacing for cold water conduit in floor screeds
Terminating the conduit
For terminating the conduit pipe at wall and floor finish level
for direct 15mm connections to appliances, a conduit terminal
fitting is available (HX101/15). For floor terminations the plastic
housing may be drilled through the base to allow fixing. Floor termination procedure (see Fig. 45).
Fig. 43 HX101/15
15mm conduit terminal
Fig. 44 HX103 terminal
back plate
Fig. 45 HX101/15 conduit terminal installation procedure
Terminating the conduit continued
Fig. 46 HX101/15, 15mm
conduit terminal and HX103
terminal back plate
Fig. 47 HX103, terminal
back plate and HX6/15
wall plate elbow
For wall terminations the HX103 terminal back plate can be used to mount two terminals side by side (see Figs. 44
and 46) or it can be easily split to form two single plates.
The same terminal back plate can also be used to fix a
maximum of four wall plate elbows (see Fig. 47).
Fig. 48 Installation of HX102 terminal fitting plate and
HX101/15, 15mm conduit terminal
Hep2O Pipe-in-Pipe system
This consists of Hep2O Barrier pipe (see page 9) pre-sheathed
in conduit ready for underscreed installation. This saves time and effort whilst complying with the current
regulations. Hep2O Pipe-in-Pipe is available in manageable
coil lengths, and the conduit is available in red and blue to aid identification.
Fig. 49 Hep2O Pipe-in-Pipe is supplied in coils with a choice of
red or blue conduit
Heating Systems
Dry lined wall feeds for radiators
There are distinct advantages to using 10mm Hep2O pipe
instead of microbore copper feeds to radiators. Hep2O
pipe can easily be accommodated behind ‘dot and dab’
plasterboard (see Hep2O within internal drywall system on
page 48) to give a pipe-free appearance within a room,
but unlike copper, it is not susceptible to damage such as
dents or kinks which can be caused on ‘soft’ copper by other
follow-on trades.
radiator valve
90° spigot
Pipe clip
90° Elbow
90° spigot elbow
Fig. 50 Radiator pipework in 10mm Hep2O within dry lined walls
Radiator outlet cover plate
A neat solution when using 10mm Hep2O pipe, is to utilise the
HX113 Hep2O Radiator Outlet Cover Plate. This cover plate,
fitted in conjunction with a back box provides an exceptionally
neat and easy to install method of connecting radiators. It also
has the benefit of a hinged flap that provides an airtight seal.
The box is fixed in a central position behind the radiator with
the 10mm pipes dropping out to the radiator valves. This gives
a smart professional finish where little or no pipe is seen and
for new build provides an anchor point for the pipework prior
to plastering/boarding (see Fig. 51 on page 44).
Heating Systems
1. Position back box centrally
behind radiator location with
adequate pipe for left or
right connection
2. Fit cover plate which provides
an airtight seal when closed
3. Pipework can now be left
until follow-on trades have
finished working
4. The result leaves little or no
pipe on show
Fig. 51 Installation procedure of HX113 cover plate
First-fix radiator feeds
The following is good practice for first-fix pipework:
•For conventional connections to radiators, the pipe
drops should run vertically, side by side at one end of the radiator position.
•Where a radiator outlet cover plate is used, the radiator
drops should run vertically, side by side, to the centre of the radiator position.
•Lateral pipes should be run horizontally through the
stud work, avoiding any obvious fixing zones such as skirting boards.
Where subsequent wall fixings are likely, metallic tape
should be used to enable an electronic pipe detector
to be used (see page 33).
For fixing pipework to lightweight blockwork, use wooden
dowels at each clip position. The HX65 pipe clip is not suitable
for fixing directly to such walls because of the low pull-out
resistance of the nail.
Heating Systems
Connecting Hep2O pipe to storage vessels
and radiators
Although Hep2O pipe is compatible with most other makes
of fittings, when connecting it to cylinders, radiators etc.
Hep2O fittings should be used wherever possible. If an
appropriate fitting is not available from the Hep2O range,
a recognised brand should be used.
The Hep2O range includes double check valves, tank
connectors, gate valves, stopcocks and cylinder connectors.
If the use of compression fittings is unavoidable then the
jointing instructions outlined in the section, ‘Connection Using Compression Fittings’ (see page 21) should be
carefully followed.
•Do not use any jointing compound on the jointing shoulder
of the cylinder connector, use only PTFE tape.
•Do not use any jointing compound when fitting tank
connectors, use only sealing washers.
Fig. 52 Hep2O tank connector
Connecting Hep2O to ancillaries
(pumps, valves, etc.)
When connecting Hep2O to ancillary items, it is important
to follow the guidance in the section ‘Connections Using
Compression Fittings’ (see page 21).
Hep2O pipework must be clipped adjacent to the outlets of
the pumps and valves using Hep2O screw pipe clips (code
HX85). This ensures adequate support and reduces vibration
in the majority of cases. Where it is felt that the weight of the
connected equipment merits extra support, metal brackets
should be used. Where the size of the pump and/or valve
requires fixing at a greater distance from the wall than can be
accommodated by the pipe clip alone, this can be augmented
with a pipe spacer (HX86). This will allow a greater ‘stand-off’
distance whilst maintaining security.
Heating Systems
Connecting boilers and heaters
Where boilers incorporate a high limit cut out thermostat,
pump overrun device and have connections outside the boiler
casing 350mm from the heat source, direct connection can be
made using Hep2O. Typically these boilers contain a copper
heat exchanger and are low water content boilers.
Where the above criteria for direct connection to a boiler
cannot be met a minimum one metre run of copper pipe
should be installed between the boiler and the start of the
Hep2O system.
Where individual boiler manufacturers instructions state
differently, they should always be followed.
In all cases including instantaneous water heaters, caravan
heaters etc. care must be taken to ensure that appliances
have the appropriate thermostatic controls and cut outs
to ensure that operating conditions do not exceed the
temperature and pressure limits laid down for Class S pipe.
(see Table No.1 - page 7).
For any type of back boiler, all the water connections should
be extended from the appliance to the outside of the fireplace
opening using copper pipe.
Any gravity circuit of a solid fuel boiler should always be
installed in copper. Regulations require that metal pipe be
used as the discharge pipe from temperature/pressure relief
valves on unvented water heaters, to or from a tundish, or from safety valves on sealed central heating systems. On sealed systems where the safety valve is not provided
within the boiler casing, the pipe between the safety valve and the boiler should be in copper. All boiler connections
should be made in accordance with the requirements of BS 5955, part 8.
During commissioning it is important to ensure that all
trapped air is purged from the heating system before
the boiler is operated. ‘Pockets’ of air can effect
proper circulation and impair the correct operation
of boiler temperature controls, and this can cause
severe overheating.
Heating Systems
Hep2O 10mm manifolds are particularly suited to microbore
plumbing and are available in 2 and 4 port versions. They are
designed primarily for use in central heating systems but can
also be used for hot and cold water supplies. Hep2O 15mm
manifolds are available in 2 and 3 port versions.
A Hep2O manifold is a single fitting which brings together
multiples of 10mm or 15mm pipe, on the flow or return
pipework, to one area of a building, enabling easy access.
A comprehensive range of Hep2O manifolds is available,
and these can be connected in series to allow any number of outlets. Alternatively, a range of ‘spigot tee’ fittings can be coupled together to give independent 360° joint rotation.
Fig. 53 Hep2O manifolds are used to connect multiples
of 10mm or 15mm pipe
Heating Systems
Installation and performance benefits
•Choice of 2, 3 or 4 port manifolds reduce the number
of fittings required to connect 22mm pipe to 10mm or 15mm pipe.
•Manifolds reduce the number of fittings required
and cut installation time.
•Manufactured from Polybutylene, an extremely robust
yet lightweight material, they are easy to install.
•Lightweight Polybutylene manifolds enable pipe to
be suspended between joists without fear of it being
dragged down.
•Hep2O blanking pegs can be used to close off any
unused sockets.
Hep2O within internal drywall systems
The Hep2O system can easily be cabled within timber
studwork and within wall systems (eg. Paramount Board)
during construction. This method is often used for running
feeds to radiators or where concealed plumbing is necessary,
e.g. supplies to a recessed shower mixer.
A connection for a radiator can be made by using a secured
elbow in the wall and fixing a plastic snap-on escutcheon to
neatly cover the hole through the wall surface.
Alternatively for 10mm Hep2O a dry lining box can be used
which gives the advantage of allowing minor alignment
adjustment to the ‘tail’ during ‘second-fix’ (see Fig 54) and
allowing access to the elbow. ‘First-fix’ pipework should follow
the good practice advice in the text headed ‘Dry lined wall
feeds to radiators’ described above, and ‘pipes adjacent to
metalwork’ (see page 34).
To radiator
Dry lining box
and cover plate
(single gang
electrical fitting)
elbow (HD5/10)
Non load-bearing
internal drywall system
Fig. 54 Radiator
connection using 10mm
Hep2O and a dry lining
box within a drywall
This solution can
also be used where
the radiator is fed from
below in which case
the risers should be
located directly under
each box.
Heating Systems
Hep2O within timber framed and steel
framed buildings
The Hep2O system is ideal for use within both timber framed
and steel framed buildings but consideration must be given to:
1.Early detection of leaks which could damage the building
fabric if left unattended. Resultant repair delays would also
contravene Water Bylaws.
2.Installation of the pipework which should be on the warm
side of any thermal insulation layer. It must also be possible
to replace any pipes which pass through vapour control
layers without affecting the integrity of the layer.
To comply with the above, pipework should either be run
within a recessed duct designed by the architect, or run within
a conduit system. Whichever method is used it is necessary to
consider the detail at the junction between the wall and floor
to avoid floor joist problems and to agree pipe penetrations
at header rails/bottom rails. For radiator connections, 10mm
Hep2O within conduit pipe may be used (see Fig. 55).
When cutting
vapour control
care should be
taken not to
displace vapour
control material
To radiator
conduit pipe
Fig. 55 Radiator
connection using
10mm Hep2O within
timber or steel framed
external wall
The conduit
be firmly
within dry
lining box
Dry lining box
and cover plate
(single gang
electric fitting)
Heating Systems
General advice
•For drilling holes through timber joists (see Figs. 30 and 31). •Within steel framed buildings, pipework should be routed
through preformed holes in steelwork wherever practicable.
No holes should be formed in steelwork without the
approval of the architect. See text headed ‘Pipes adjacent to
metalwork’ (see page 34).
•Do not lay pipework in areas where plasterboard is likely
to be fixed.
•Care should be taken to ensure pipework located within
compartments or passing through party walls or floors does
not impair the fire rating of the building.
Fig. 56 Installation is quicker and easier due to the flexibility
of the Hep2O system
Important Information
Continuously operated re-circulating systems
(Secondary Hot Water Circulation / Ring
main installations)
A continuously operated re-circulating system is a water-replenished circulating system which is maintained at a constant high temperature to provide a constant source of hot water.
Continuously operated re-circulating systems are used to
distribute constant hot water to draw off points that may be
distant from the heat source or hot water storage vessel.
Continuously operated re-circulating systems are very different
from conventional hot water supply and central heating
systems found in domestic properties, for which our products
have been tested to, under either BS 7291 2010 Class S
or WRAS approval standards, and for this reason Hep2O
products must NOT be used on any continuously operated
re-circulating systems as they are not approved under the
current version of these standards.
Freezing for maintenance/system modification
Hep2O pipe can be frozen for maintenance/repairs
without damage to the system. When freezing equipment,
manufacturers' instructions should be followed. Always freeze
at a reasonable distance from where pipe is to be cut.
Painting Hep2O
Hep2O can be painted. In fact, painting is strongly advised
for outdoor applications to protect the pipe from the effects
of sunlight and ultra violet light. Painting with emulsion
paint is preferred but oil based gloss paint can also be used
in conjunction with undercoat. Before painting, ensure all
surfaces are clean, free of grease and dry. Cellulose based
paints, paint strippers or thinners must not be used.
Use of corrosion inhibitors
Corrosion of metals is a hazard in all installations therefore it is essential that possible causes of corrosion are kept to a minimum.
To provide maximum system protection, independent of
pipe material, all heating circuits should be protected using
an inhibitor. Fernox and Sentinel have been tested and are
suitable for use with Hep2O pipe and fittings.
Oxygen will almost always be present in any system as it can enter through a variety of points. Hep2O Barrier pipe
incorporates an additional oxygen barrier to reduce the ingress
of oxygen through the pipe wall. It is accepted by
Important Information
British Gas and is suitable for use in heating systems which
specify SuperWarm, GasWarm or are covered by British Gas
Contract Service.
Antifreezes based on Ethylene Glycol mixtures will not have
any adverse effect on Hep2O, however if there is any doubt,
please contact our Technical Advisory Service – Tel: 0844 856 5165.
Electrical safety
Hep2O does not conduct electricity therefore there is no risk
of electric shock, and the practice of utilising metal pipework
system for earthing was discontinued in 1966.
However, if Hep2O forms a break in the continuity of existing
metal pipework which may have been used for earthing or
bonding, the electrical continuity must be reinstated by fixing
the bonding lead permanently to both ends of the existing
metal pipework. For further information contact the Technical
Advisory Service – Tel: 0844 856 5165, or for information on
electrical safety and the IEE regulations, contact a registered
electrical contractor or your local electricity provider.
Equipotential bonding
A Hep2O installation requires no more and in many cases
needs less equipotential bonding than metal pipework.
Woodworm / timber treatment
When treating timber for woodworm or rot, aqueous based solutions are generally accepted, and it is preferable
to carry out any such spraying prior to Hep2O being installed.
Where this is not practical, care should be taken to protect
and cover Hep2O pipe and fittings prior to any spraying.
Please note that solvent based treatments should not be used.
For further information contact the Technical Advisory Service
– Tel: 0844 856 5165.
External installations
If Hep2O is installed outdoors or in an unheated environment,
it should be protected from frost in accordance with BS 5422, BS 6700, Water Bylaws and Building Regulations
Approved Document L.
Hep2O should be protected from the effects of ultraviolet
radiation. If insulation has been installed to avoid freezing this
provides adequate protection. Where insulation is not used,
painting or covering is recommended.
Testing has demonstrated that vermin do not show a
preference for Hep2O over other materials. However, all items
which are softer than rodents’ teeth are liable to be gnawed in vermin infested property. If vermin infestation is suspected, a reputable rodent exterminator should be consulted. If vermin are present they may damage Hep2O pipework.
Hep2O will not be affected by the levels of chlorine expected
in the UK water supply (typically less than 0.5ppm), nor will
short term chlorination for disinfection have an adverse effect
on the system.
However, high sustained concentrations of chlorine will have an adverse effect on plastic pipe. Hep2O is therefore
not suitable for use in systems where the water contains a high concentration of chlorine e.g. swimming pools or
decorative water features.
Pressure testing
When testing Hep2O pipework systems, the recommended
test is 1.5 times working pressure.
If the system contains ANY earlier version grab-ring or
SlimLine fitting, a further test to a maximum of 18 bar should
always be undertaken, but any non-Hep2O appliances or
fittings that will not withstand testing at 18 bar should be
disconnected – check with other manufacturers instructions.
The duration of the test should be not less than 1 hour in
accordance with BS 6700.
Fig. 57 Pressure testing
Valve 1
Valve 2
Fig. 58 Pressure testing kit (HX81)
Testing procedure
1.Disconnect any non-Hep2O components that will not
withstand the test pressure.
2.Blank off all open ends using Hep2O blanking pegs
‘System alterations’ (see page 24).
3.Connect pressure hose to system at a convenient point
using a Hep2O socket.
4.Close valve V2 and open valve V1 (see Fig. 58).
5.Completely fill system to be tested with water and purge
all air.
6.Raise pressure to test pressure and close valve V1
(see Fig. 58).
7.At end of test duration, tap gauge (to ensure pointer is ‘free’)
and read pressure on gauge. If there is no appreciable drop
in pressure, the system is watertight.
8.Release valve V1 and V2 to release pressure and drain
system if necessary.
Pressure testing is NOT a substitute for making sure the
pipe has been correctly inserted into the Hep2O fittings.
This should be achieved by following the correct jointing
procedure and wherever possible, checking the joints
using Hep2O joint recognition technology as detailed
(see page 15).
Special Application
Hep2O is resistant to corrosion and light in weight.
This makes it ideally suited to marine applications.
The flexibility of Hep2O pipe means it can be cabled around
the interior cavities of boats and easily hidden behind
bulkheads. The mechanical flexibility of the Hep2O system
also allows it to absorb vibrations from the engine and forces
of the sea which may cause soldered or compression joints to crack or work themselves loose. Hep2O is impervious to
electrolytic corrosion and performance is further assured
through jointing technology which carries a 50 year guarantee.
Hep2O is ideal for caravans where its lightness and flexibility
allows fitting in confined spaces without damage to the fabric of the vehicle, or adding unduly to the kerbside weight.
Resistance to corrosion and freezing make Hep2O an obvious
choice for this application.
Easy to install and dismantle, Hep2O provides an ideal
solution. The temporary nature of exhibitions combined with the requirement that services be run for considerable
distances with multiple take-off points, requires a plumbing
system which is flexible and capable of regular dismantling
and re-installing to different layouts. A Hep2O system answers
all the requirements for flexibility and economy.
Portable buildings, site cabins, toilets etc.
The Hep2O range includes all the necessary items to
ensure compliance with local Water Bylaws (e.g. double check
valves) whilst allowing the building to be moved
to another location when required, with the minimum disruption to internal systems. Hep2O is the ideal choice
for these structures.
Agriculture and horticulture
Inherent durability and resistance to corrosion and cold weather make Hep2O ideal for many applications
in agricultural and horticultural environments. Typical
applications include water supplies to milking parlours,
drinking troughs and horticultural watering systems.
Fault Finding
In the unlikely event of a problem occurring, the following
notes will help to identify the cause:
Typical Problems
1.Joint weeps
Probable causes:
a. Deeply scored or scratched pipe.
Evidence: Visual inspection of pipe.
b. Pipe has been inserted through grab-ring but not
through O-ring.
Evidence: Joint leaks but pipe remains in fitting.
c. Dust or burrs under O-ring seal (usually occurs if a
hacksaw has been used to cut the pipe).
Evidence: Contamination evident on visual examination
of components.
d. O-ring seal has been damaged, usually by the insertion
of a sharp ended copper pipe), or the pipe support sleeve
has been omitted.
Evidence: Cause evident on visual examination
of the component.
e. Fitting may have been connected to old Imperial copper.
Evidence: Measurement of pipe will reveal discrepancy
with current standard diameter (BS 2871 Part: 1 1971).
2. Split fittings
Probable cause:
Formation of ice within a system containing metal pipework,
or adjacent to metal taps. Evidence: Splitting of fitting or fitting pulled off pipe after
severe cold spell.
Water freezes at 0°C and increases 9% in volume.
Hep2O pipe can absorb this volume increase without
rupture, but if metal pipe or components are involved
in the system, the extra pressure generated may
occasionally be sufficient to
split the fitting.
Fault Finding
3.Pipe or fitting melting
Probable causes:
a. Melting point of Polybutylene is approximately 125°C.
Direct contact with any naked flame, electric fire, or hot flue pipe etc. would cause the pipe to melt.
b. Water/steam within pipe reaches temperatures in excess
of normal boiler safety and malfunction levels. This is very
rare and if found should initiate a thorough investigation
of both heating and electric systems. One cause has been
found to be stray electric current passing through impurities
in water.
Evidence: Visual examination shows material to be
deformed. Surface of material may appear ‘glossy’. If in any doubt please return the pipe and fitting to the
Technical Advisory Department for further analysis.
If a fitting is being returned, care should be taken not
to damage the sample which may hinder analysis.
As much of the affected installation should be returned
as possible, but sufficient pipe should be left in fittings
to allow pressure testing (minimum requirement 50mm).
If possible a full metre of pipe should be returned complete
with markings or a note made of all pipe markings.
The above notes cover some possible malfunctions generally
resulting from incorrect installation or service conditions. By following the procedures and advice contained in this
guide these problems will be avoided.
General Information
Advisory service
Wavin provides a comprehensive range of support services to
ensure that any queries are dealt with swiftly and efficiently.
Hep2O is a professional product and is distributed nationwide
via a network of builders’ and plumbers’ merchants. It is not
available through DIY or other retail outlets.
For details of your nearest Hep2O stockist visit our website
Other sources of information
The Plumbing Engineering Services Design Guide published
by: The Institute of Plumbing.
Building Regulations - Approved Documents A, G and L.
BS 5449: Code of Practice for Central Heating for
Domestic Premises.
BS 5955: Part 8: Specification for the installation of
themoplastics pipes and associated fittings for use in
domestic hot and cold water services and heating systems.
BS 6700: Design, Installation, Testing and Maintenance of
services supplying water for domestic use within buildings and
their curtilages.
The Water Bylaws Listed in the Water Fittings and Materials
Directory listing number 0112066.
This guide follows requirements stated in the standards,
byelaws and regulations listed previously. Should it differ from
any new UK or European requirements issued since we went
to print, please obtain clarification by calling the appropriate
enquiry hotline.
Technical Advisory Service:
Tel 0844 856 5165
Literature Service:
[email protected]
[email protected]
Web Site:
Registered Office:
Wavin Limited, Hazlehead, Crow Edge, Sheffield S36 4HG
©Wavin 2009. Hep2O is a registered trademark of Wavin. Wavin operates a programme
of continuous improvement, and reserves the right to modify or amend the specification of
products without notice. All information in this publication is believed correct at the time of going
to press. However, no responsibility can be accepted for any errors or omissions.
PL311 – Hep2O 10/10
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