vd brochure.indd - Halogenated Solvents Industry Alliance Inc

vd brochure.indd - Halogenated Solvents Industry Alliance Inc
Chlorinated Solvents - The Key to
Surface Cleaning Performance
June 2008
Typical Properties of Chlorinated Solvents
Methylene
Chloride
Perchloroethylene
Trichloroethylene
1,1,1-Trichloroethane
Chemical Formula
CH2Cl2
C2Cl4
C2HCl3
C2H3Cl3
Molecular Weight
84.9
165.8
131.4
133.4
104 (40)
250 (121)
189 (87)
165 (74)
-139 (-95)
-9 (-23)
-124 (-87)
-34 (-37)
Specific Gravity @ 68oF
(g/cm3)
1.33
1.62
1.46
1.34
Pounds per gallon @ 77oF
10.99
13.47
12.11
11.10
Vapor Density (air = 1.00)
2.93
5.76
4.53
4.55
Vapor Pressure @ 77oF
(mm Hg)
436
18.2
74.3
123
71
14.5
12
2.1
30
4.5
37
6.0
Specific Heat @68oF
(cal/g per oC or BTU/lb per oF)
0.28
0.205
0.225
0.25
Heat of Vaporization (cal/g)
@ boiling point
78.9
50.1
56.4
56.7
Viscosity (cps) @ 77oF
0.41
0.75
0.54
0.79
Solubility (g/100 g)
- water in solvent
- solvent in water
0.17
1.70
1.01
0.015
0.04
0.10
0.05
0.07
Surface Tension @68oF
(dynes/cm)
28.2
32.3
29.5
25.6
Kauri-Butanol (KB) Value
136
90
129
124
Flash Point
- tag open cup
- tag closed cup
none
none
none
none
none
none
none
none
13
23
none
none
8
11
8
13
Boiling Point oF (oC)
@ 760 mm Hg
Freezing Point oF (oC)
Evaporation Rate @ 77oF
- ether=100
- n-butyl acetate=1
Flammable Limits (% solvent in air)
- lower limit
- upper limit
Information in this brochure is believed to be correct as of the publication date, but HSIA can not guarantee its completeness or accuracy.
HSIA does not assume or undertake any duty imposed on any other party by law or regulation. It is the user’s responsibility to determine
the suitability of the products and processes mentioned in this paper.
The Key to
Surface Cleaning Performance
Today's manufacturing engineers and plant managers
can face a difficult challenge when choosing among
the many available surface cleaning options. Aqueous,
semi-aqueous, flammable, combustible, fluorinated
and brominated solvents are just a few of the possibilities. Among these many choices, however, one
process stands out for its ability to produce a clean,
dry part at a reasonable price -- vapor degreasing with
the chlorinated solvents.
Trichloroethylene (TRI), perchloroethylene (PERC) and
methylene chloride (METH), have been the standard
for cleaning performance in precision parts cleaning for
more than 50 years. Today, the development of new
equipment and processes that minimize emissions
and maximize solvent recovery makes TRI, PERC,
and METH more effective than ever.
Despite their superior performance attributes, however, some companies have replaced TRI, PERC, or
METH with other solvents or processes. Their decision
was based on misperceptions about the chlorinated
solvents' regulatory status, continued availability, and
safety in use. The facts are:
TRI, PERC, and METH have not been
banned. Among the commonly used chlorinated solvents, only 1,1,1-trichloroethane
(methyl chloroform) was phased out of production, due to its ozone depletion potential.
Meanwhile, the U.S. Environmental Protection
Agency (EPA) has issued a 1994 decision
under its Significant New Alternatives Policy
(SNAP) program that the other three chlorinated solvents are viewed as acceptable
substitutes for ozone depleting solvents.
as a result of their use as raw materials in the
production of refrigerant alternatives to CFCs.
METH continues to be used in a wide variety of
applications. The producers of these solvents
remain committed to serving their markets for
many years to come.
TRI, PERC, and METH can be used safely.
From the point of view of health and the environment, the chlorinated solvents are among
the most thoroughly studied industrial chemicals. Animal tests and epidemiological studies
indicate that when the solvents are handled,
used, and disposed of in accordance with
recommended and mandated practices, they
do not cause adverse health or environmental
effects.
The potential impacts of the solvents can
be minimized. Environmental, health, and
safety regulations governing the chlorinated
solvents are strict, but manageable. In complying with these regulations companies can
get help from several sources – EPA, the
Occupational Safety and Health Administration (OSHA), and state and local agencies,
producers and distributors of solvents and
degreasing equipment, and organizations like
the Halogenated Solvents Industry Alliance.
Far from replacing chlorinated solvents with alternative cleaning technologies, manufacturers may wish
to seriously consider surface cleaning with chlorinated
solvents as the most efficient, effective and economical
cleaning process for precision products.
Chlorinated solvents will continue to be
available. TRI and PERC demand has remained steady or increased in recent years
engineers and managers
face a difficult
challenge choosing
a cleaning option
Principles of Vapor Degreasing
The vapor degreasing process is the ideal technology
for high quality cleaning of parts. It is able to remove
the most stubborn soils. It reaches into small crevices
in parts with convoluted shapes. Parts degreased in
chlorinated solvent vapors come out of the process dry,
with no need for an additional drying stage.
Vapor degreasing is particularly effective with parts that
contain recesses, blind holes, perforations, crevices,
and welded seams. Chlorinated solvent vapors readily
penetrate complicated assemblies as well. Solid particles such as buffing compounds, metal dust, chips,
or inorganic salts contained in the soils are effectively
removed by the washing action of the solvent vapor.
Vapor degreasing can be carried out in either a batch or
an in-line degreaser. The traditional batch degreaser is
a covered tank, with cooling coils at the top, into which
the dirty parts are lowered. Solvent in the bottom of
the tank is heated to produce vapor. On contacting
the cooler work, the vapor condenses into pure liquid
solvent. The condensation of solvent dissolves the
grease and carries off the soil as it drains from the
parts into the solvent reservoir below. This process
continues until the parts reach the temperature of the
vapor, at which point condensation ceases and the
parts are lifted out of the vapor, clean and dry.
Many degreasers contain one or several immersion
tanks below the vapor zone, so that parts can be lowered into liquid solvent – often in a tumbling basket
– before being raised into the vapor for final rinsing.
Ultrasonic cleaning can be added to remove heavy oil
deposits and solid soils by installing transducers in the
degreaser. When ultrasonic energy is transmitted to
a solution, it imparts a scrubbing action to the surface
of soiled parts through cavitation – the rapid buildup
and collapse of thousands of tiny bubbles.
Several types of conveyorized equipment provide inline vapor degreasing. These large, automatic units,
which can handle a volume of work and are enclosed
to provide minimal solvent loss, include the monorail
and the cross-rod degreasers. They are particularly
valuable when production rates are high.
Although conveyorized degreasers are enclosed, there
is still some solvent loss through the openings where
work enters and leaves the equipment. Consequently,
some companies have found it cost effective to install
one of the advanced types of degreasers that have
no air/vapor interface. These sealed units were first
introduced in Europe, but have become available in
the United States in recent years.
Typically these degreasers perform the cleaning
operation in a sealed chamber into which solvent is
introduced after the chamber is closed. Solvent vapor
then performs the final drying stage, and all vapors
are exhausted after each cycle and passed into a
solvent recovery system. With the sealed chamber,
control of solvent loss exceeds 90 percent. Operation
is programmed and automated, permitting a variety of
cleaning programs, including hot solvent spray.
Although these sealed units can be costly and may not
be effective for some cleaning jobs, a few U.S. plants
have installed them to ensure compliance with safety
and environmental regulations.
Solvent Properties
TRI, PERC, and METH are clear, heavy liquids with excellent solvency. All are virtually nonflammable, since
they have no flash point as determined by standard test
methods. Each has its own advantages for specific applications, based on its physical profile (see inside front
cover). These solvents work well on the oils, greases,
waxes, tars, lubricants, and coolants generally found
in the metal processing industries. They are widely
used in the vapor degreasing process.
TRI has been long recognized for its cleaning power.
TRI is a heavy substance (12.11 pounds per gallon)
with a high vapor density (4.53 times that of air) that
allows for relatively easy recovery from vapor degreasing systems. The solvent’s ability to provide constant
pH and to protect against sludge formation has helped
make it the standard by which other degreasing solvents are compared. Its high solvency dissolves soils
faster, providing high output.
TRI is used extensively for degreasing zinc, brass,
bronze and steel parts during fabrication and assembly.
It is especially suited for degreasing aluminum without
staining or pitting the work, because its stabilizer system protects the solvent against decomposition. For
cleaning sheet and strip steel prior to galvanizing, TRI
degreases more thoroughly and several times faster
than alkaline cleaning, and it requires smaller equipment that consumes less energy.
PERC has the highest boiling point, weight (13.47
pounds per gallon), and vapor density (5.76 times
that of air) of the chlorinated solvents. PERC’s high
boiling point gives it a clear advantage in removing
waxes and resins that must be melted in order to be
solubilized. The higher temperature also means that
more vapors will be condensed on the work than with
other solvents, thus washing the work with a larger
volume of solvent.
PERC is effective in cleaning lightweight and lightgauge parts that would reach the operating temperature of lower-boiling solvents before cleaning is
complete. When cleaning parts with fine orifices or
spot-welded seams – especially if there is entrapped
moisture – PERC’s high boiling point is essential for
obtaining good penetration.
Inherently more stable than other chlorinated (and
brominated) solvents, PERC also incorporates a multi-
component stabilizer system that provides the greatest
resistance to solvent decomposition available in the
industry. While it can be used to degrease all common
metals, PERC is especially applicable to cleaning those
which stain or corrode easily, including aluminum,
magnesium, zinc, brass, and their alloys.
METH has the lowest boiling point of the chlorinated
solvents, as well as the lightest vapor density (2.93
times that of air) and weight (10.98 pounds per gal).
METH is uniquely suited for use as a vapor degreasing
solvent in applications where low vapor temperatures
and superior solvency are desirable. The low boiling
point of METH makes it a popular choice for cleaning
temperature-sensitive parts such as thermal switches
or thermometers.
Vapor degreasing with METH allows more rapid processing and handling, particularly when cleaning large,
heavy parts. The more aggressive nature of METH
is especially useful when degreasing parts soiled with
resins, paints, or other contaminants that are difficult
to remove.
Environmental Considerations
In reviewing the acceptability of TRI, PERC, and METH
in its SNAP review, EPA noted that these compounds
are regulated under several other environmental laws
and regulations, including the occupational limits and
national emission standards described elsewhere in
this brochure. The Agency concluded that compliance with these regulations will significantly reduce
the potential for environmental releases and worker
exposure from degreasing operations. As a result, the
SNAP program does not impose further use restrictions
on the three solvents in degreasing.
Three cleaning substitutes were found to be “unacceptable” under the SNAP program because of their
significant ozone depletion potential – hydrochlorofluorocarbon (HCFC) 141b, dibromomethane, and
chlorobromomethane. Another brominated solvent,
n-propyl bromide or nPB, is listed as acceptable under
SNAP based on the ability of existing equipment to
control worker exposure.
Two other solvents or solvent classes – HCFC 225
and the perfluorocarbons (PFCs) – are listed by EPA
as “acceptable subject to use conditions” under SNAP.
According to the Agency, they may only be used in
electronics and precision cleaning for high performance, precision-engineered parts when companies
have made reasonable efforts to ascertain that alternatives are not feasible due to performance or safety
requirements. EPA also specifies that companies using HCFC-225 meet the manufacturer-recommended
occupational limit of 50 parts per million (ppm) for an
eight-hour time-weighted average (TWA).
TRI, PERC, and METH
are excellent solvents with
no flash point
Results of Life Cycle Assessment
(per square meter of metal part cleaned)
Nonrenewable Resource Depletion (kg/year)
Total Energy Use (MJ)
Greenhouse Effect (g equiv. CO2)
Solid Waste (Kg)
Air Pollution (g equiv. H+)
Water Pollution (g equiv. PO4 3-)
Scenarios: VD1 - open-top degreaser without NESHAP-compliant controls; VD2 - NESHAP-compliant degreaser with on-site
distillation; VD3 - NESHAP-compliant degreaser with on-site distillation and carbon adsorption; AQ1 - aqueous cleaning with
primary wastewater treatment; AQ2 - aqueous cleaning with primary and secondary wastewater treatment and drying.
Source: LCA Comparison of Metallic Parts Degreasing with Trichloroethylene and Aqueous Solutions, Ecobilan, December 1996.
Life Cycle Assessment
Competitors and others frequently propose replacing
one of the chlorinated solvents with an alternative for
cleaning metal parts. Indeed, alternatives such as
water and detergents are often perceived as having
less environmental impact than vapor degreasing with
TRI. In 1997, the European Chlorinated Solvents Association (ECSA) sponsored a “life cycle assessment”
to provide robust data comparing the environmental
impact of metal parts cleaning in TRI with aqueous
processes.
Each cleaning technology was found to have potentially significant environmental impact. The primary
disadvantage of TRI, air pollution (i.e., air acidification), can be minimized with emission controls. The
water pollution disadvantages of aqueous cleaning,
however, can remain significant even after treatment
of the cleaning residues is applied. With aqueous
cleaning, impact on water was between 200 and 2,000
times higher than with TRI degreasing, depending on
the site under consideration.
advantages, it can be generally concluded that:
Aqueous cleaning is best for producing clean
and wet metal parts. In this case, even the
best TRI scenario studied (i.e., with carbon adsorption) had a greater environmental impact
than the aqueous technologies studied.
Enclosed solvent degreasing is best to produce clean and dry metal parts, even without
carbon recovery. Thus, solvent cleaning is
preferable when the subsequent treatment
requires dry parts.
For cleaning and drying metal parts, TRI degreasing
was found to have a lower overall environmental impact
than aqueous technology. This is true provided that
equipment complies with EPA emission standards (see
below). While air pollution with TRI degreasing can be
relatively high, use of technologies to reduce solvent
release can minimize this impact.
While both TRI degreasing and aqueous cleaning
technologies have environmental strengths and dis-
Regulatory Controls
U.S. federal regulations affecting the use, handling,
transportation, and disposal of chlorinated solvents can
be found under the Clean Air Act, the Clean Water Act,
the Occupational Safety and Health Act, the Resource
Conservation and Recovery Act (RCRA), and the Comprehensive Environmental Response Compensation
and Liability Act (CERCLA, or Superfund). State and
local regulations also exist for the purpose of controlling emissions. Though numerous, these regulations
are manageable and companies can obtain compliance assistance from numerous sources. Federal
regulations pertaining to the chlorinated solvents are
summarized below.1
Volatile Organic Compound (VOC) regulations under
the Clean Air Act apply to TRI and limit its emissions in
order to reduce smog formation, particularly in ozone
non-attainment areas. Exact requirements vary by
state, but generally include obtaining a permit allowing
a specific amount of VOC emissions from all sources
within a facility. PERC and MC, however, are exempt
from VOC regulations in most states.
The Clean Air Act also calls for the three chlorinated
solvents to be regulated as hazardous air pollutants.
EPA has issued a National Emission Standard for
Hazardous Air Pollutants (NESHAP) for solvent cleaning with halogenated solvents, which is discussed in
96% of companies feel that
cleaning performance is the
most important attribute of a
solvent or process
1
This is not intended as a complete listing of regulations that may apply to degreasing with chlorinated solvents. It is important that each
individual company determine just how these regulations apply to your business, as well as whether additional state and local regulations
may apply.
detail on the next page. Other NESHAPs govern drycleaning with PERC and the use of MC in aerospace
manufacture and rework, wood furniture manufacture,
and polyurethane foam manufacture.
The Clean Water Act defines chlorinated solvents
as toxic pollutants and regulates their discharge into
waterways. Under RCRA, wastes containing chlorinated solvents from solvent cleaning operations are
considered hazardous. Generators, transporters, and
disposers of such hazardous waste must obtain an
EPA ID number.
The Superfund law requires that if a reportable quantity
of a chlorinated solvent or other hazardous chemical is
released into the environment in any 24 hour period,
the federal, state, and local authorities must be notified
immediately. Reportable quantities are 1000 pounds
(lbs.) for METH and 100 lbs. for PERC and TRI.
OSHA has set permissible exposure limits (PELs) for
chlorinated solvents. The PEL for PERC and TRI is 100
ppm for an 8-hour TWA. The limits for METH are 25
ppm for an 8-hour TWA and 125 ppm for a 15-minute
short term exposure limit, or STEL. In addition to the
TWA and STEL, the OSHA standard for METH imposes
several additional requirements. The American Conference of Governmental Industrial Hygienists (ACGIH),
moreover, recommends Threshold Limit Values®, or
TLVs, for the chlorinated solvents. The solvent producers recommend maintaining workplace exposure levels
within the OSHA limits or the ACGIH levels, whichever
is lower (see inside back cover).
OSHA’s Hazard Communication (HAZCOM) standard specifies a minimum element of training for
people working with hazardous materials, including
the chlorinated solvents. This includes how to detect
the presence or release of a solvent, the hazards of
the solvent, and what protective measures should be
used when handling it.
OSHA’s HAZCOM standard also regulates the labeling
of all hazardous chemicals. Labels must contain a hazard warning, the identity of the chemical, and the name
and address of the responsible party. Guidelines are
provided by an OSHA compliance document (OSHA
Instruction No. CPL-2-2.38 D (1998)) and by the American National Standards Institute (ANSI) publication on
precautionary labeling (ANSI Z129.1-1994).
In an open-top degreaser, although the vapor generally stays below the primary condensing coils, there
can still be considerable solvent loss. Drafts in the
work area cause solvent vapor to be pulled out. Parts
loading disturbs the solvent/air interface and causes
losses. In addition, cleaned parts may carry solvent
with them when removed from the degreaser. These
factors can cause an uncontrolled open-top degreaser
to lose up to 70 percent of the solvent over a year.
Consequently, procedures are necessary to minimize
this loss to ensure compliance with environmental and
occupational requirements.
EPA’s Degreasing NESHAP
EPA’s NESHAP for new and existing halogenated solvent cleaning operations governs emission standards
for chlorinated solvent degreasing operations. These
standards cover both vapor degreasing and cold cleaning with TRI, PERC and MC.
In developing the standards, EPA focused on equipment and work practice requirements which permit a
level of control between 50 and 70 percent. Companies
operating batch or in-line degreasers are given three
options for compliance:
Installing one of several combinations of
emission control equipment and implementing
automated parts handling and specified work
practices;
Meeting an idling-mode emission limit, in conjunction with parts handling and work practice
requirements; or
Meeting a limit on total emissions.
The multiple compliance options in the NESHAP
recognize the vast number of different industries and
operating schedules associated with the use of halogenated solvent cleaners. EPA’s standard allows
companies considerable flexibility in complying with the
control requirements. The alternative idling and total
emissions limits allow the use of new and innovative
technologies to achieve a level of control equivalent
to the available equipment combinations.
Recent amendments to the NESHAP also imposed
facility-wide emission limits on companies that vapor
degrease with the chlorinated solvents. The annual
limits, including emissions from all the degreasing units
at a facility vary depending on the solvent - 60,000
kilograms, or kg, (132,000 lbs) for METH, 14,100 kg
(31,000 lbs) for TRI, and 4,800 kg (10,500 lbs) for
PERC. Higher limits - 100,000 kg for METH, 23,500
kg for TRI, and 8,000 kg for PERC - apply to federal
facilities involved in the maintenance of military vehicles. An exemption from the facility-wide limits for
narrow tube manufacturing, aerospace manufacture
and, and facilies operating continuous web cleaning
equipment is the subject of litigation and currently is
being reconsidered by EPA.
Equipment and Work Practices
When a company chooses the equipment option to
comply with the NESHAP, it may choose from a series
of combinations of two or three procedures, which
include:
Freeboard ratio of 1.0: The height of the freeboard above vapor level must be equal to the
width (shorter dimension) of the degreaser.
Freeboard refrigeration device: A refrigerated
system which supplements the traditional
water cooling system and creates a cold air
blanket above the vapor zone.
Reduced room draft: Air movements above
the freeboard must be kept at or below 50 feet
per minute (15.2 meters per minute).
Working-mode cover: A cover or machine design that shields the machine from outside air
disturbances during the parts cleaning cycle.
Dwell: The time in which cleaned parts remain
in the freeboard area above the vapor zone
after cleaning. EPA defines proper dwell time
as 35 percent of the time required for the parts
to cease dripping in the vapor zone.
Superheated vapor: Use of vapor maintained
10o F above the boiling temperature of the
solvent. This promotes more thorough drying of the work before it is removed from the
degreaser.
ries parts at a controlled speed of 11 feet per minute
or less through the complete cleaning cycle.
Compliance with one of the control options for batch
or in-line vapor equipment is demonstrated by periodic
monitoring of each of the control systems chosen.
Work practices are also required as part of the new
EPA standards. Rather than require direct monitoring
of work practice compliance, however, EPA has developed a qualification test, included as an appendix
to the standard. The test is to be completed by the
operator during inspection, if requested.
Emission Limits
A company choosing to comply with the second
NESHAP option, the idling-emission limit (0.045 lbs/
ft2-hour for batch vapor equipment, 0.021 lbs/ft2-hour
for in-line equipment), is required to demonstrate initial
compliance by using EPA’s idling reference test method
307. Data from the equipment manufacturer may be
used, provided the unit tested is the same as the one
for which the report has been submitted. Compliance
with the idling-emission limit also requires installation
of an automated parts handling system and compliance
with the work-practice requirements under the . In addition, the company must show that the frequency and
types of parameters monitored on the solvent cleaning machine are sufficient to demonstrate continued
compliance with the idling standard.
Complying with the third option, the limit on total
emissions, requires the company to maintain monthly
records of solvent addition and removal. Using massbalance calculations, the company calculates the total
emissions from the cleaning machine, based on a
three-month rolling average, to ensure they are equal
to or less than the established limit for the cleaner
(30.7 lbs/ft2-month for small batch vapor machines,
31.4 lbs/ft2-month for large batch vapor machines,
20.3 7 lbs/ft2-month for in-line machines). For new
machine designs without a solvent/air interface, EPA
has established an emission limit based on cleaning
capacity ( = 330 x (vol)0.6).
In addition to these options, solvent cleaning processes
must include an automated hoist or conveyor that car-
EPA provides considerable
flexibility in complying with
the degreaser NESHAP requirements
Companies meeting the total emission limit requirements do not need to conduct monitoring of equipment
parameters, but must maintain records of their solvent
usage and removal of waste solvent. According to
EPA, this compliance option provides an incentive for
innovative emission control strategies to limit solvent
use. For some cleaning machines, EPA calculates that
the alternative total emission limit could be more stringent than the equipment specifications. In particular,
EPA expects that this alternative standard will be more
difficult to meet for larger machines, for machines operating more than one shift, and for machines cleaning
parts with difficult configurations.
For Further Information
Users of chlorinated solvents can obtain help in meeting regulated standards, and in applying emission
control procedures, from a number of sources.
The 1990 Amendments to the federal Clean Air Act
mandate EPA to provide funding to each state to set up
a small business assistance program (SBAP). State
SBAPs provide a state Small Business Ombudsman
and a Technical Assistance Director to facilitate communications between the EPA and small businesses
and to provide information on new and existing environmental regulations and policies. To qualify as a
small business, a company must have fewer than 100
employees and must not be “dominant in its field.”
The federal Small Business Ombudsman provides
literature and a toll-free hot-line to answer questions,
although primary assistance for a business comes
from the state SBAP office. You can find out whom
to contact on a state level by calling the federal Small
Business Ombudsman’s hot line, 1-800-368-5888, or
visiting the website, www.epa.gov/smallbusiness.
Producers and distributors of chlorinated solvents also
provide support for solvent users. Federal law requires
these companies to provide a Material Safety Data
Sheet (MSDS), containing complete information on
safety and handling, to all customers. In addition, the
Responsible CareTM initiative of the Chemical Manufacturers Association and the Responsible Distribution
ProcessTM of the National Association of Chemical
Distributors require members to share product stewardship information on use, disposal, and regulatory
compliance with customers.
HSIA provides legislative and regulatory news to the
industry, sponsors research on chlorinated solvents,
and presents information to EPA, OSHA, and other
regulatory agencies in support of solvent users. Companies can obtain information and literature from HSIA
on use of the solvents and applicable regulations by
calling the Alliance at 703-741-5780, or visiting our
website at www.hsia.org.
Operating Parameters for the Chlorinated Solvents
Methylene
Chloride
Perchloroethylene
Trichloroethylene
1,1,1-Trichloroethane
Vapor Thermostat Setting
o
F (oC)
95 (35)
180 (82)
160 (71)
130 (54)
Boil Sump Thermostat Setting1
o
F (oC)
110 (43)
260 (127)
195 (91)
175 (79)
1 -3
40 - 60
5 - 15
1-6
Solvent Condensate Temperature2 100 (38)
o
F (oC)
190 (88)
155 (68)
130(54)
Cooling Coil Outlet Temperature
Range (oF)
75 - 85
100 - 120
100 - 120
100 - 120
25
125
-
100
200
300
100
200
300
350
-
50
-
25
100
10
25
350
450
Steam Pressure (psi)
Occupational Exposure Limits
OSHA PELs3
- 8-hour TWA
- 15-minute STEL
- Ceiling
- Peak
ACGIH TLVs4
- 8-hour TWA
- 15-minute STEL
1
2
3
4
Maximum boiling temperature, based on 25-percent contamination with oil.
To facilitate effective separation of the solvent from the water.
8-hour time weighted average (TWA) is an employee's permissible average exposure in any 8-hour work shift of a 40hour week. The short-term exposure limit (STEL) is a 15-minute TWA exposure that should not be exceeded at any
time during a work day. The Acceptable Ceiling Concentration is the maximum concentration to which a worker may
be exposed during the shift, except that brief excursions to the Acceptable Maximum Peak are permissible.
Threshold Limit Values (TLVs) are established by the American Conference of Governmental Industrial Hygienists
(ACGIH).
Sources:
ASTM Standard D3698 Standard Practice for Solvent Vapor Degreasing Operations; ACGIH Guide to Occupational
Exposure Values (2008); 29 CFR 1910.1052; and 29 CFR 1910.1000, Table Z-1 - Limits for Air Contaminants.
Halogenated Solvents Industry Alliance
1300 Wilson Boulevard - 12th Floor
Arlington, Virginia 22207
703-741-5780 X 703-741-6077 (fax)
www.hsia.org
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