I 

CALIFORNIA CLEAN AIR ACT 

GUIDANCE 

CALIFORNIA ENVIRONMENTAL PROTECTION AGENCY 

8- Air Resources Board 

RACTIBARCT 
State of California 

AIR RESOURCES BOARD 

DETERMINATION OF REASONABLY AVAILABLE CONTROL TECHNOLOGY 

AND BEST AVAILABLE RETROFIT CONTROL TECHNOLOGY 

FOR 

OR6ANIC SOLVENT CLEANING AND DEGREASING OPERATIONS 

Prepared by 

Criteria Pollutants Branch 

Stationary Source Division 

and the 

Solvents Comnittee 

Approved by 

The Technical Review Group of the 

California Air Pollution Control Officers Association 

July 18, 1991 
ACKNOWLEDGMENTS 

This determination was prepared by the Air Resources Board staff in 

cooperation with the California Air Pollution Control Officers 

Association's Technical Review Group Solvents Committee. We would like to 

particularly thank: 

Clerical Sup~ort 

Marline Hicks 

Theresa Dade 

Technical Review Grow 

Solvents Committee 

Eric Skelton, Chairman 

Bill Davis 

Laki Tisopulos 

Wayne Kino 

Don Price 

Natalie Zlotin 

Don Ames 

Dean Simeroth 

Tom Evashenk 

Sacramento Metropolitan AQMD 

U.S. EPA 

South Coast AQMD 

Bay Area AQMD 

Ventura County APCD 

San Diego County APCD 

ARB 

ARB 

ARB 

. . rinci~al Author 

Bill Riddell 

Peter D. Venturini, Chief, Stationary Source Division 

Ronald A. Friesen, Assistant Chief, Stationary Source Division 

Dean C. Simeroth, Chief, Criteria Pollutants Branch 

Gary M. Yee, Manager, Industrial Section 
Contents Paae 

INTRODUCTION AND SUMMARY ............................................. 1 

I . RACT/BARCT RECOMMENDATION ...................................... 3 

I1 . CONTROL TECHNOLOGY ........................................ 7 

A . Equipment Controls ..................................... 7 

B . Operational Controls ........................................ 9 

111 . COST EFFECTIVENESS ........................................... 11 

IV . IMPACTS ........................................................ 12 

A . Economic Impacts ............................................ 12 

B . Emission Reductions ......................................... 13 

C . Other Impacts ............................................... 13 

V . REFERENCES ..................................................... 14 

APPENDICES 

A . RACT/BARCT DETERMINATION 

B . SIGNIFICANT COMMENTS AND RESPONSES AT MAY 20. 1991 WORKSHOP 
RACTIBARCT DETERMINATION 

FOR 

ORGANIC SOLVENT CLEANING AND DEGREASING OPERATIONS 

INTRODUCTION AND SUMMARY 

This report presents the determination of reasonably available control 

technology (RACT) and best available retrofit control technology (BARCT) 

for controlling volatile organic compound (VOC) emissions from solvent 

cleaning and degreasing operations. This report also discusses the basis 

for the determination, the overview of the control technology and costeffectiveness, and economic and other impacts. This determination is 

applicable to all organic solvent cleaning and degreasing operations. 

Solvent cleaning is a term used for the cleaning of oil, grease and 

other material from surfaces by dissolving or dispersing them in organic 

solvents which do not adhere to the surface being cleaned. Solvent 

cleaning is done prior to operations such as assembly, coating, plating and 

repair. The three basic types of solvent cleaning processes are cold 

solvent cleaning, solvent vapor cleaning and conveyorized solvent cleaning. 

Cold cleaning is the imnersion of the material to be cleaned in a solvent 

tank or the use of a fluid flow into a remote reservoir in which the 

solvent may be heated but not to its boiling point. Solvent vapor cleaning 

involves boiling the organic solvent and placing the material to be cleaned 

in the solvent vapors above the liquid solvent. In this case, cooling 

coils are placed near the top of the cleaner (the solvent cleaning tank) to 

condense the solvent vapors and reduce the amount of evaporation into the 

atmosphere. Conveyorized solvent cleaners use a conveyor system to move 

material into and out of cold cleaners or vapor cleaners in a continuous 

process. 

Most VOC emissions occur from solvent cleaning operations when 

solvents are exposed to the atmosphere both during active cleaning and 
idling. VOC emissions also occur from equipment leaks and waste solvent 

disposal. The staff estimates that VOC emissions from solvent cleaning 

operations in California were approximately 58 tons per day in 1987. 

The development of the RACTIBARCT determination for solvent cleaning 

and degreasing operations consisted of reviewing the solvent cleaning rules 

of several air pollution control districts (districts). In addition, the 

Air Resources Board (ARB) model rule for solvent cleaning and documents 

from the Environmental Protection Agency (EPA) that assess methods to 

control volatile organic emissions from solvent cleaning were reviewed. 

From the review of district rules, the degreasing rules of the South Coast 

Air Quality Management District (SCAQMD), the Bay Area Air Quality 

Management District (BAAQMD), the Ventura County Air Pollution Control 

District (APCD), the San Diego County APCD and the Santa Barbara County 

APCD were selected to make a final comparative evaluation to identify the 

most effective standards for the determination of RACT and BARCT. The 

development of the determination of RACT and BARCT was also made in 

cooperation with the Solvents Cornittee of the Technical Review Group. 

There are 27 districts with existing solvent cleaning rules and 14 

districts without such rules. Most existing rules are similar to the 

determination's major requirements. For districts without rules, many 

facilities already meet most of the requirements since solvent cleaning 

equipment manufacturers supply the same equipment to these districts as 

supplied to regulated districts. Staff estimates that full implementation 

of the determination's requirements could achieve between a 2 to 10 percent 

reduction (about 1 to 6 tons per day) in the statewide emission inventory 

for this source category. Although this emission reduction is small, staff 

believes that the development of the determination is necessary to provide 

districts with guidance for developing rules that are uniform as required 

by the California Clean Air Act. 
I. RACT AND BARCT RECOMMENDATION 

Staff recormends that the determination (See Appendix A) be defined as 

RACT and BARCT for organic solvent cleaning and degreasing operations. For 

the purpose of this determination, RACT and BARCT are considered the same 

level of control. The determination requires equipment and operating 

criteria for general solvent cleaning, cold cleaning, vapor cleaning, and 

conveyorized cleaning as summarized in Table 1. The following is a brief 

discussion of the main elements of the determination. 

RACTIBARCT Discussion 

The RACTIBARCT determination is structured according to equipment and 

operating requirements for several solvent cleaning categories. Equipment 

requirements include criteria that are specific to the design of the 

equipment such as freeboard ratios, refrigerated chillers, covers, and 

emission collection and control systems that reduce or control emissions. 

For example, cold cleaners must have a freeboard not less than 6 inches 

for cleaners using only low volatility solvents as defined in the 

determination. For cold cleaners using high volatility solvents and for 

vapor cleaners, a minimum freeboard ratio of 0.75 is required unless an 

alternative control system is provided. For conveyorized cleaners, a 

freeboard chiller or alternative control device may be used, in lieu of a 

minimum freeboard ratio of 0.75, when the freeboard ratio is not physically 

verifiable. 

The determination includes c r i t e r i a f o r operating requirements to 

minimize leaks and solvent carry-out, specified ventilation rates, and 

disposal of waste solvent residues. Another requirement includes limits on 

work load areas to minimize VOC emissions during use and standby. The 

determination exempts emulsions or solutions which contain two percent or 

less of volatile organic compounds. The compliance schedule requires full 

compliance within one year after the date of adoption of the determination. 
Table 1 

Solvent Cleaning, Degreasing Operation 

RACT/BARCT Sumnary 

Standards 

Equipment Standards: 

o All cleaners shall be equipped with the following equipment: 

- A cover where appropriate, 

- A label specifying operating instructions 

o Cold cleaners shall be equipped with: 

- At least a 6 inch freeboard for low volatility solvents. 

- At least a 0.75 freeboard ratio for all other solvents, or 

- A water cover, if solvent is insoluble in and heavier than water 

o Batch-loaded vapor cleaners shall be equipped with: 

If the surface area of the air-vapor interface is less than 1 square 

meter, 

- A primary condenser. 

- A vapor level control thermostat. 

- A condenser flow switch. 

- A spray safety switch. 

- A freeboard ratio at least 0.75. 

If the surface area of the air-vapor interface is greater than or 

equal to 1 square meter, 

- A primary condenser. 

- A vapor level control thermostat. 

- A condenser flow switch. 

- A spray safety switch. 

- A freeboard ratio at least 0.75. 

- A refrigerated freeboard chiller. 

o Conveyorized cold cleaners shall be equipped with: 

- A rotating basket. 

- An average clearance less than 10 centimeters or less than 10% 

of the opening width. 

- A physically verifiable freeboard ratio at least 0.75 or a 

refrigerated freeboard chiller. 

continued 
Table 1 f~ontinued) 

o Conveyorized vapor cleaners shall be equipped with: 

- An enclosed drying tunnel or rotating basket. 

- An average clearance less than 10 centimeters or less than 10% 

of the opening width. 

- A primary condenser. 

- A condenser flow switch. 

- A spray safety switch. 

- A vapor level control thermostat. 

- A physically verifiable freeboard ratio at least 0.75, or 

a refrigerated freeboard chiller. 

A1 ternat ive Control Standard: 

Alternatively, a collection and control system that can achieve at 

least 85% overall efficiency can be used in lieu of the freeboard 

ratio and chiller requirements. 

Operating Standards: 

o Maintain equipment in a no leak condition. 

o Cover container when not in use. 

o Do not clean porous or absorbing materials such as cloth, leather, 

wood or rope. 

o Spray as a fluid stream and prevent splashes outside of container. 

o No visible solvents in the water exiting from water separator. 

o Rack parts for drainage. 

o Vertical hoist speed does not exceed 3.3 m/m (11 fpm). 

o Retain workload below the air-vapor interface until condensation 

ceases, as applicable. 

o Tip out any pool of solvent and do not remove any part until it is 

visually dried. 

o Follow start-up and shut down sequences. 

o Maintain the area occupied by the work load at 50% or less of the 

evaporative surface area of container. 

o All solvents and wipe cleaning materials containing solvent shall be 

stored in closed containers. 

o Solvents, residues, and cleaning materials containing solvent shall 

be disposed of properly. 

continued 

-5- 
New lip exhaust, unless it is vented to a control device. 

tiona 

o Cleaning operations using emulsions or solutions that contain no 

more than 2% of VOC (wt) in the solvent as determined by EPA 

Method 24. 

o Cold cleaners with less than 1 square foot of exposed solvent 

surface area. 

liancs Schedule 

Be in full compliance one year from the date of adoption. 

o ASTM 0-1078-86 for the determination of the initial boiling point of 

solvent. 

o ASTM 0-4457-85 for analyzing exempt compounds. 

o EPA Capture Efficiency Testing Document for the determination of the 

capture efficiency of collection devices. 

o EPA Method 25 for the determination of the control efficiency of 

control device. 

o EPA Methods 2, 2A, 2C, 2D for the determination of volumetric 

flowrate of the collection system. 

o EPA Method 24 for the determination of VOC content. 

Test methods are specified for the determination of initial boiling 

point, the analysis of samples, capture and control efficiency, volumetric 

flowrate and exempt compounds. Record-keeping requirements are also 

included. 

The determination does not discuss the control of exempt compounds or 

toxic compounds. Decisions regarding these compounds are left to the 

districts. 
11. CONTROL TECHNOLOGY 

Control technology refers to both equipment and operating control 

measures. Equipment controls are equipment specific and reduce the 

evaporation of solvent from cleaning tanks and associated equipment by 

design. Operational controls relate to operational techniques to minimize 

solvent evaporation. Various control measures and associated control 

efficiencies are shown in Table 2. 

A. Equipment Controls. 

1. Solvent Tank Evaporation Controls. 

These controls include freeboard ratios, coveys, remote 

reservoirs, freeboard chillers, refrigerated freeboard chillers, and 

equipment to provide solvent drainage. Freeboard ratio is a number 

which indicates how high above the liquid solvent or the solvent 

vapor-air interface the cleaner walls must extend. Increasing the 

ratio or the height of the cleaner wall above the liquid or 

solvent/vapor interface minimizes solvent evaporation. Covers are 

designed to prevent emissions from openings in the cleaner tank 

above the liquid level. 

Remote reservoirs are solvent containers connected to a sink by 

a small opening. The small opening reduces the size of the surface 

area available for solvent evaporation and significantly reduces the 

effect of drafts (air flow) on the rate of evaporation. During 

cleaning, the solvent is pumped to the sink and then falls through 

the hole back into the reservoir. 

Freeboard chillers and refrigerated freeboard chillers prevent 

evaporation by lowering the air temperature at the solvent vaporlair 

interface, causing the vapor to condense. Refrigerated chillers can 

achieve control efficiencies up to 40 percent. 
Table 2 

Control Equipment and Control Efficiencies 

VOC Control EaCold Cleaner (low volatility) 

o cover 

o mechanically assisted cover and 

spray and agitation control 

Cold Cleaner (high volatility) 

o cover 

o mechanically assisted covers and 

spray and agitation controls 

Batch-loaded Vapor Cleaner 

o cover 

o mechanically assisted covers and 

spray and agitation controls 

Conveyorized Vapor Cleaner 

o cover 

o mechanically assisted covers and 

spray and agitation controls 

Carbon Adsorbers 

Refrigerated Chillers 

Higher Freeboard Ratio 

Use of Non-VOC Solvents 

A typical value is about 40 percent. 

For a batch-loaded vapor cleaner. 

Based on a baseline freeboard ratio of 0.5 for batch-loaded vapor 

cleaners. Increasing the ratio from 0.5 to 0.75 and 1.0 results in 

about 25 and 50 percent emission reduction, respectively. 

Sources: References 1 and 2. 
2. Carry-out Emission Controls. 

Carry-out emissions are those from the solvent remaining on 

material when it is removed from a cleaner. Those emissions can be 

reduced by a variety of methods which keep more of the solvent 

inside the cleaner. These methods include rotating baskets, open 

racks or baskets to hold parts, and rack or basket holders inside 

the solvent container. Drying $nnels are used with some 

conveyorized vapor cleaners. 

3. Enclosure and Add-on Controls. 

Enclosures and associated col lection/control devices col lect 

solvent emissions and reduce the amount of emissions to the 

atmosphere. Enclosures with minimized entrance and exit openings 

reduce the amount of surface area available for evaporation. 

Enclosures with collection/add-on devices can achieve overall 

control efficiencies between 40-95 percent. 

B. Operational Controls. 

1. Proper Use of Equipment. 

A conspicuous label providing proper equipment operating 

instructions should be attached to solvent cleaning equipment. The 

instructions are designed to minimize solvent evaporation by operator 

education. 

2. Minimize Disturbance of the Air-vapor Interface. 

Disturbance of the air-vapor interface can affect solvent 

evaporation. Minimizing disturbances can be accomplished by reducing 

the work-load of vapor cleaners, controlling spraying and solvent 

agitation techniques, minimizing fan speeds and exposure to drafts, 
establishing maximum operating temperatures for the refrigerated 

freeboard chiller, and reducing the vertical speed of a hoist or 

conveyor when moving or removing clean parts. 

3. Use of Alternative Solvents. 

Alternative solvents have been and are currently used as a means 

to comply with regulations that control VOCs. Alternative solvents 

include halogenated compounds, aqueous-based detergents, nonhalogenated emulsions (such as terpene-based solutions), and partial ly 

hydrogenated or blends of partially hydrogenated chlorofluorocarbons 

with nonhalogenated solvents. These solvents have comparable or 

better cleaning characteristics over conventional solvents. However, 

these solvents can have disadvantages which include: 

1) increased space requirements, 2) higher energy usage (especially 

with aqueous systems), 3) longer drying times or the need of a 

separate dryer, and 4) increased wastewater discharge. 

Presently, the continued use of alternative solvents is 

questionable, since many of these solvents can cause toxic health. 

effects, or may impact global warming and stratospheric ozone 

depletion. In response to these adverse impacts, many regulatory 

entities are restricting the use of these solvents. For example, the 

1990 amendments to the Federal Clean Air Act require that the 

production of l,l,l-trichloroethane be terminated by January 1, 2002. 

In California, many local districts have developed policies to 

regulate the use of halogenated solvents and toxic compounds. Some 

districts already regulate halogenated compounds. Also, districts 

are required to regulate toxic compounds as specified in Chapter 3.5 

of the California Health and Safety Code, which delineates 

California's identification and control program for toxic air 

contaminants. Presently, solvents such as methylene chloride and 

percholorethylene are being considered in this process. 
4. General Housekeeping and Maintenance. 

General housekeeping and maintenance consists of the following: 

o Proper disposal and containment of contaminated material, 

o Proper disposal of waste solvents and residual, 

o Maintenance and repair. 

111. COST-EFFECTIVENESS 

The cost of implementing the determination is dependent on the degree 

of compliance a facility must make to meet the requirements of the 

determination. EPA estimates (Reference 1) indicate that cost savings can 

occur when covers are used or solvent distillation is practiced. 

Additionally, complying with operational requirements should result in 

minimal costs. However, costs for some equipment retrofits may be 

significant. 

ARB staff has estimated the cost-effectiveness of retrofitting a 

batch-loaded vapor cleaner with a refrigerated freeboard chiller. The 

cost-effectiveness ranges from $2.00 per pound for a cleaner with a working 

area of 0.42 square meters (4.5 square feet) to $1.00 per pound for a 

cleaner with a working area of 1.5 square meters (16 square feet). The 

cost-effectiveness for retrofitting a freeboard chiller on a conveyorized 

cleaner can result in a cost savings. These estimates are based on data 

obtained from the EPA (Reference 6). In addition to this, staff has 

obtained the following cost-effectiveness estimates from the SCAQMD 

(Reference 4). Raising the freeboard ratio of batch-loaded vapor cleaners 

from 0.75 to 1.0 would result in a cost-effectiveness of $0.10 per pound of 

VOC reduced. 
The cost of hoods and add-on control systems can be significant for 

most batch-loaded vapor cleaners. Staff estimates that the costeffectiveness for batch-loaded vapor cleaners equipped with carbon 

absorbers to range from $2 per pound to $14 per pound. However, for most 

conveyorized vapor cleaners add-on control systems are more cost-effective. 

EPA estimates (Reference 6) the cost-effectiveness of a carbon absorber on 

a conveyorized vapor cleaner to be $0.70 per pound. 

IV. IMPACTS 

A. Economic Impacts. 

There are 27 districts with existing solvent cleaning rules 

that will require upgrading to some extent. Additionally, there 

are 14 districts that do not have solvent cleaning rules. As 

mentioned before, staff believes that most facilities located in 

districts with or without rules are in compliance with most of the 

determination's requirements. Therefore, staff estimates that the 

economic impact to most facilities, including small businesses, 

will be minimal. 

For facilities that may need to retrofit their equipment to 

comply with the determination's requirements, significant economic 

impacts may result. Staff estimates that the cost-effectiveness 

for retrofitting existing equipment with the anticipated controls 

will range from $1.00 to $2.00 per pound of emissions reduced. 

These cost-effectiveness values are within acceptable limits 

contained in many past control measures. 

B. Emission Reductions. 

Emissions from solvent cleaners can be reduced by 10 to 100 

percent, depending on the type and size of the equipment, and the 

type of controls applied. Staff estimates that the net emission 

reductions achieved by the implementation of the determination's 
requirements to be nominal; about 1 to 6 tons per day, statewide. 

This nominal reduction in emissions is due to the current 

compliance status of facilities. Staff estimates that many 

facilities are in compliance with most of the requirements of the 

determination. 

C. Other Impacts. 

Staff has identified no adverse environmental impacts 

associated with the implementation of the RACT/BARCT standards 

with respect to global warming, plant and animal life, noise 

levels, waste disposal, land use or natural resources. 
V. REFERENCES 

1. Alternate Control Technoloav Document - loaenated Solvent 

Cleaners, United States Environmental Protection Agency, Office 

of Air and Waste Management, Office of Air Quality Planning and 

Standards, Emissions Standards Division, Research Triangle Park, 

North Carolina 27711, EPA-450/33-89-030, August 1989. 

2. California Clean Air Act Guidance. Determination of Reasonablv 

Available Control Technoloav and Best Available Retrofit Control 

Jechnoloay, State of California Air Resources Board, Stationary 

Source Division, April 1990. 

3. Consideration of a Proposed Model Rule for the Control of 

Yolati le Oraanic Cempsund Em1 ss Ions from Oraanic Solvent . . 

Deareasina Ooerations, State of Cal ifornia Air Resources Board, 

Sacramento, CA, August 1978. 

4. Control of Volatile Oraanic Emissions from Solvent Metal . . 

Cleaning, United States Environmental Protect ion Agency, Off ice 

of Air and Waste Management, Office of Air Quality Planning and 

Standards, Research Triangle Park, North Carolina 27711, 

November 1977. 

5. Final Air Oualitv Management Plan. 1989 Revision. Ap~endix IV A. . . - 

Jier I. Tier 11. and Continwncv Control Measures, South Coast 

Air Quality Management District, March 1989. 

6. Studv to Support New Source Performance Standards for Solvent 

Metal Cleanina O~erations, Final Report, June 30, 1976, Dow 

Chemical Company, Midland, Michigan. 
APPENDIX A 

RACTIBARCT DETERMINATION 
DETERMINATION OF REASONABLY AVAILABLE CONTROL TECHNOLOGY 

AND BEST AVAILABLE RETROFIT CONTROL TECHNOLOGY 

FOR 

ORGANIC SOLVENT CLEANING AND DEGREASING OPERATIONS 

APPLICABILITY. 

Except as provided in Section V., this determination shall apply to 

all volatile organic compound solvent cleaning and degreasing 

operations. 

DEFINITIONS 

A. Air-Vapor Interface means the top of the solvent-vapor layer, and 

the air touching this layer. 

0. Batch-loaded means material placed in a nonconveyorized container 

for cleaning. 

C. Cold Cleaner means any cleaner using solvent which, if heated, is 

maintained below the initial boiling point temperature. The 

cleaners include, but are not limited to, remote reservoirs, spray 

sinks and batch-loaded dip tanks. 

D. Condenser (or primary condenser) means a device, such as cooling 

coils, used to condense (liquify) solvent vapor. 

E. Condenser Flow Switch means a safety switch connected to a 

thermostat which shuts off the sump heater if the condenser 

coolant is either not circulating or exceeds its designed 

operating temperature. 

F. Control Device means a device for reducing emissions of VOC to the 

atmosphere. 

G. Conveyorized Solvent Cleaner means any conveyorized cold or vapor 

solvent cleaner, including but not limited to gyro, vibra, 

monorail, cross-rod, mesh, belt and strip cleaners. Strip 

cleaners clean material by drawing the strip itself through the 

unit for cleaning prior to coating or other fabrication processes. 

H. Emulsion means a suspension of small droplets of one liquid in a 

second liquid. 

I. Evaporation means to change into a vapor, normally from a liquid 

state. 

J. Evaporative Surface Area means: 

(1) Cold Cleaner: 

(a) The surface area of the top of the solvent. 

(b) The surface area of the solvent sink or work area for a 

remote reservoir. 

(2) Vapor Solvent Cleaner: The surface area of the top of the 

solvent vapor-air interface. 

(3) Conveyorized Solvent Cleaner: 

(a) Cold Cleaner: The surface area of the top of the solvent. 

(b) Vapor Solvent Cleaner: The surface area of the top of the 

solvent vapor-air interface. 

K. Executive Officer means the Executive Officer or Air Pollution 

Control Officer, or his or her delegate, of an air quality 

management district or an air pollution control district. 
L. Freeboard Height means: 

(1) Cold Cleaner: The vertical distance from the top of the 

solvent, or the solvent drain of a remote reservoir cold 

cleaner, to the top of the cold cleaner. 

(2) Batch-loaded Vapor Solvent Cleaner: The vertical distance from 

the top of the solvent vapor-air interface to the top of the 

solvent cleaner. 

(3) Conveyorized Solvent Cleaner: 

(a) For non-boiling solvent, the vertical distance from the top 

of the solvent to the bottom of the lowest opening in the 

solvent cleaner where vapors can escape. 

(b) For boiling solvent, the vertical distance from the top of 

the solvent vapor-air interface to the bottom of the lowest 

opening in the solvent cleaner where vapors can escape. 

M. Freeboard Ratio means the freeboard height divided by the smaller 

of the inside length or the inside width of the solvent cleaner 

evaporative area. 

N. Initial Boiling Point means the boiling point of a solvent as 

defined by ASTM D-1078-86. 

0. Leak means 3 or more drops of liquid solvent per minute. 

P. Lip Exhaust means a system which collects solvent vapors escaping 

from the top of a cleaner and directs them away from personnel 

using the cleaner. 

Q. Low Volatility Solvent means a aolventowith an initial boiling 

point which is greate~ than A20 C (248 F) and with a temperature 

as used, at least 100 C (180 F) below the initial boiling point. 

R. Make-up Solvent means that solvent added to the solvent cleaning 

operation to replace solvent lost through evaporation or other 

means. 

S. Refrigerated Freeboard Chiller means a secondary cooling coil 

mounted above the primary condenser which provides a chilled air 

blanket above the solvent vapor air-interface to cause the 

condensation of additional solvent vapor. 

T. Remote Reservoir means a cold cleaner with a tank which is 

completely enclosed except for a solvent return opening no larger 

than 100 square centimeters which allows used solvent to drain 

into it from a separate solvent sink or work area and which is not 

accessible for soaking workloads. 

U. Solvent means compounds which are used as diluents, thinners, 

dissolvers, viscosity reducers, cleaning agents or for other 

similar uses. 

V. Spray Safety Switch means a manually reset switch which shuts off 

the spray pump if the vapor level drops more than 10 cm (4in). 

W. Ultrasonics means enhancement of the cleaning process by agitation 

of liquid solvents with high frequency sound wave vibrations. 

X. Vapor Level Control Thermostat means a manually reset safety 

switch which turns off the sump heater if the thermostat senses 

the temperature rising above the designed operating level at the 

air-vapor interface. 
Y. Vapor Solvent Cleaner means any solvent cleaner that cleans 

through the condensation of hot solvent vapor on colder workloads. 

Z. Volatile Organic Compound means any compound containing at least 

one atom of carbon, except methane, carbon monoxide, carbon 

dioxide, carbonic acid, metallic carbides or carbonates, ammonium 

carbonate, l,l,l-trichloroethane, methylene chloride, 

trichlorofluoromethane (CFC-ll), dichlorodifluoromethane (CFC-12), 

chlorodifluoromethane (HCFC-22), trifluoromethane (HFC-23), 

trichlorotrifluoroethane CFC-113), dichlorotetrafluoroethane (CFC114), chloropentaf luoroethane (CFC-115), dichlorotr if luoroethane 

(HCFC-123), 2-chloro-1,1,1,2-tetraf luoroethane (HCFC-124), 

pentaf luoroethane (HFC-125), 1,1,2,2-tetraf luoroethane (HFC-134), 

tetraf luoroethane (HFC-134a), dichlorof luoroethane (HCFC-14lb), 

chlorodifluoroethane (HCFC-142b), l,l,l-trifluoroethane (HFC143a), 1,l-difluoroethane (HFC-152a), and the following four 

classes of perfluorocarbon (PFC) compounds: 

1) cylic, branched, or linear, completely fluorinated 

a1 kanes ; 

2) cyclic, branched, or linear, completely fluorinated 

ethers with no unsaturations; 

3) cylic, branched, or linear, completely fluorinated 

tertiary amines with no unsaturations; and 

4) saturated sulfur containing perfluorocarbons with sulfur 

bonds only to carbon and fluorine. 

AA. Volatile Solvent means any solvent that is not a low volatility 

solvent. 

BB. Waste Solvent Residue means material which may contain dirt, oil, 

metal particles, and/or other waste products concentrated after 

heat distillation of the waste solvent either in the solvent 

cleaner itself or after distillation in a separate still. 

CC. Wipe Cleaning means that method of cleaning which utilizes a 

material such as a rag wetted with a solvent, coupled with a 

physical rubbing process to remove contaminants from surfaces. 

DD. Workload means the objects put in a cleaner for the purpose of 

removing oil, grease, soil, coating, dirt or other undesirable 

matter from the surface of the objects. 

EE. Workload area means: 

(1) The plane geometric surface area of the top of the submerged 

parts basket, or 

(2) The combined plane geometric surface area(s) displaced by the 

submerged workload, if no basket is used. 

111. STANDARDS. 

A. Equipment Requirements. 

(1) All cleaners shall be equipped with the following: 

(a) An apparatus or cover(s) which reduces solvent evaporation, 

except as provided in Section III.A.2. 

(b) A permanent, conspicuous label summarizing the applicable 

operating requirements contained in Section 1II.C. 
(c) A device for draining cleaned parts which permits the 

drained solvent or drag-out to be returned to the cleaner 

solvent tank. 

(2) Remote Reservoir Cold Cleaners shall be equipped with all of 

the following: 

(a) A sink or work area which is sloped sufficiently towards 

the drain to prevent pooling of solvent. 

(b) A single drain hole, not larger than 100 square centimeters 

(15.5 square inches) in area, for the solvent to flow from 

the sink into the enclosed reservoir. 

(c) Except for cleaners using low volatility solvents, a drain 

plug or a cover for placement over the top of the sink, 

when the equipment is not in use. 

(d) A freeboard height not less than 6 inches. 

(3) Cold Cleaners: 

(a) Freeboard Requirements: 

(i) Cold cleaners using only low volatility solvents which 

are not agitated, shall operate with a freeboard height 

not less than 6 inches. 

(ii) Cold cleaners (including remote reservoir cold 

cleanersb usingosolvents which are agitated, heated 

above 50 C (120 F) or volatile solvents, shall operate 

with a freeboard ratio equal to or greater than 0.75. 

(iii) A water cover may be used as an acceptable control 

method to meet the freeboard requirements, if the 

solvent is insoluble in water and has a specifie 

gravity greater than 1. 

(b) Cover Requirements: 

For cold cleaners using volatile solvents, a cover that is 

a sliding, rolling or guillotine (bi-parting) type which is 

designed to easily open and close. 

(c) A permanent, conspicuous mark locating the maximum 

allowable solvent level conforming to the applicable 

freeboard requirements. 

(4) Batch-loaded Vapor Cleaners shall be equipped with the 

following: 

(a) A cover that is a sliding, rolling or guillotine (biparting) type which is designed to easily open and close 

without disturbing the vapor zone. 

(b) A vapor level control thermostat. 

(c) A condenser flow switch. 

(d) A spray safety switch. 

(e) A freeboard ratio greater than or equal to 0.75. 

(f) A primary condenser. 

(g) In addition to the above, cleaners with an evaporative 

surface area greater than or equal to 1 square meter, shall 

be equipped with a refrigerated freebgard chiller for which 

the chilled air blanket temperature ( F) at the coldest 

point on the vertical axis in the center of the air-vapor 

interface shall be no g~eater than 30 percent of the 

initial boilingopoint ( F) of the solvent used or no 

greater than 40 F. If the chiller operates below the 
freezing temperature of water, it shall be equipped with an 

automatic defrost. 

(5) Conveyorized Cold Cleaners shall be equipped with the 

following: 

(a) A rotating basket or other method, to prevent cleaned parts 

from carrying out solvent liquid. 

(b) Minimized entrance and exit openings which silhouette the 

work loads such that the average clearance between material 

and the edges of the cleaner openings is less than 10 

centimeters (4 inches) or less than 10% of the opening 

width. 

(c) A freeboard ratio greater than or equal to 0.75 which is 

physically verifiable. 

(6) Conveyorized Vapor Cleaners shall be equipped with the 

following: 

(a) An enclosed drying tunnel or other method, such as a 

rotating basket, sufficient to prevent cleaned parts from 

carrying out solvent liquid. 

(b) Minimized entrance and exit openings which silhouette the 

work loads such that the average clearance between material 

and the edges of the cleaner openings is less than 10 

centimeters (4 inches) or less than 10% of the opening 

width. 

(c) A primary condenser. 

(d) A vapor level control thermostat. 

(e) A condenser flow switch. 

(f) A spray safety switch. 

(g) A freeboard ratio greater than or equal to 0.75 which is 

physically verifiable, or a refrigerated freeboard chiller 

for which the chilled air blanket temperature ( F) at the 

coldest point on the vertical axis in the center of the airvapor interface shall b& no greater than 30 percent of the 

initialoboiling point ( F) of the solvent used or no greater 

than 40 F. If the chiller operates below'the freezing 

temperature of water, it shall be equipped with an automatic 

defrost. 

B. Alternative Control Requirements. 

Alternatively, a system to collect emissions which are 

vented to a control device may be used to satisfy the 

requirements of I11 .A. (3)(a), I11 .A. (4) (e) and (g), 

III.A.(S)(c) and III.A.(6)(g), provided that the overall 

efficiency (the collection efficiency multiplied by the 

control efficiency) of the total system shall not be less 

than 85 percent by weight in reducing total non-methane 

hydrocarbons as determined by EPA Method 25. The collection 

system shall have a ventilation rate not greater than 20 

cubic meters per minute per square meter over the total area 

of the solvent cleaner openings unless the rate must be 

changed to meet Federal and State Occupational Safety and 

Health Administration requirements. The system must be 

approved in writing by the Executive Officer. 
C. Operating Requirements. 

(1) A1 1 Cleaners. 

(a) The solvent cleaning equipment and emission control device 

shall be operated and maintained in proper working order. 

(b) Cleaners shall not be operated when leaking. 

(c) All solvent, including waste solvent and waste solvent 

residues, shall be stored in closed containers at all 

times. The containers shall have a label indicating the 

name of the solventlmaterial they contain. 

(d) Waste solvent and residues shall be disposed of by one of 

the following methods: 

(i) A comnercial waste solvent reclamation service 

licensed by the State of California. 

(ii) At a facility that is federally or state licensed to 

treat, store or dispose of such waste. 

(iii) Recycling in conformance with Section 25143.2 of the 

California Health and Safety Code. 

(e) Solvent cleaners, except remote reservoir cold cleaners 

using low volatility solvent, shall be covered except to 

process work or to perform maintenance. 

(f) Solvent carry-out shall be minimized by the following 

methods : 

(i) Rack workload for drainage. 

(ii) Limit the vertical speed of a powered hoist, if one 

is used, to not more than 3.3 meters per minute (11 

ftlmin). 

(iii) Retain the workload below the air-vapor interface 

until condensation ceases, as applicable. 

(iv) For manual operation, tip out any pools of solvent 

remaining on the cleaned parts before removing them 

from the cleaner, and 

(v) Do not remove parts from the solvent cleaner until 

visually dry and all dripping ceases. This 

requirement does not apply to emulsion cleaner 

workload that is rinsed with water'within the 

cleaner imediately after cleaning. 

(g) The cleaning of porous or absorbent materials such as 

cloth, leather, wood or rope is prohibited. 

(h) Solvent agitation shall be achieved using pump 

recirculation, a mixer, or ultrasonics. Air agitation 

shall not be allowed. 

(i) Solvent spray shall only be a continuous fluid stream. An 

atomized or shower type spray shall not be used. In 

conveyorized cleaners, a shower type spray may be allowed 

provided that the spray is conducted in a totally confined 

space that is separated from the environment. 

(j) The solvent spray system shall not be used in a manner 

such that liquid solvent splashes outside the container. 

(k) For those cleaners equipped with water separators, no 

solvent shall be visually detectable in the water exiting 

the water separator. 
(1) Wipe cleaning materials containing solvent shall be kept 

in closed containers at all times, except during use. 

(m) A cleaner shall not be located where drafts are directed 

across the cleaner. 

(n) Drain cleaned material, within the freeboard area, so that 

the drained solvent is returned to the container. 

(2) Batch-loaded and Conveyorized Vapor Cleaners. In addition to 

the requirements in Section III.C.(l), the operating 

requirements below shall apply: 

(a) The following sequence shall be used for start-up and 

shut-down: 

(i) When starting the cleaner, the cooling system shall 

be turned on before, or simultaneously with, the sump 

heater. 

(ii) When shutting down the cleaner, the sump heater shall 

be turned off before, or simultaneously with, the 

cooling system. 

(b) The workload area shall not occupy more than half the 

evaporative surface area of the solvent cleaner. 

(c) The spray must be kept below the top of the air-vapor 

interface. 

IV. PROHIBITION. 

After the date of adoption, a lip exhaust system shall not be added 

to any cleaner, unless it is vented to a control device, as described 

in Section 1II.B. 

V . EXEMPTIONS. 

A. Solvents Containing Less Than 2% VOC. Solvent cleaning 

operations using solvent (including emulsions) containing no more 

than 2 percent of volatile organic compounds (wt) as determined 

by EPA Method 24 shall not be subject to the requirements of this 

determination. 

B. Cold Cleaners with less than 929 square centimeters (1 square 

foot) of liquid surface area are exempt from the equipment 

requirements in Section 1II.A. of this determination, except for 

the requirements that the cleaners shall be covered when work is 

not being processed. 

VI. COMPLIANCE SCHEDULE. 

Any person subject to any of the requirements of this determination, 

shall comply with the following increments of progress: 

A. By (30 days from date of adoption), be in full compliance with 

the operating requirements of this determination. 

B. By (one year after date of rule adoption), be in full compliance 

with the equipment requirements of this determination. 
VII. TEST METHODS. 

A. Initial Boiling Point of Solvent. The initial boiling point of 

the solvent shall be determined by ASTM D-1078-86. 

B. Capture Efficiency. Capture efficiency shall be determined by 

the appropriate method described in the Federal Register, "55 FR 

26865, June 29, 1990. 

C. Control Efficiency. EPA Method 25 shall be used to determine 

control efficiency, in combination with the appropriate method in 

the reference mentioned in VI1.B. 

D. Volumetric Flowate. Volumetric Flowrate shall be determined by 

EPA Methods 2, 2A, 2C and 2D. 

E. Exempt Compounds. Determination of exempt compounds, shall be 

performed in accordance with ASTM D-4457-85 (Solvents and 

Coatings) and be consistent with the provisions set forth in the 

Federal Register (FR, Vol. 56, No. 52, March 18, 1991). 

F. Volatile Organic Compounds. For the purposes of this 

determination, the content of VOCs in solvents shall be 

determined by the appropriate procedures contained in EPA Method 

24. 

VIII. ADMINISTRATIVE REQUIREMENTS. 

Solvent Records. The following records shall be retained for the 

previous 24 month period and be available at the time of a district 

inspection: 

A. Each time waste solvent or waste solvent residue is removed from 

the facility for disposal. 

B. On a quarterly or shorter basis, record the facility-wide total 

volume of make-up solvent used for a1 1 cleaners. 

APPENDIX 6 

SIGNIFICANT COMMENTS AND RESPONSES AT MAY 20, 1991 WORKSHOP 
SUMMARY OF COMMENTS AND RESPONSES 

AT THE MAY 20, 1991 RACTIBARCT WORKSHOP 

ON SOLVENT DEGREASING 

Included below are the coments presented at the workshop and 

responses by the Solvents Committee. 

Comment 1 - hn Kusz (Safetv - Kleen) 

The provision for air agitation should be excluded, since operators 

may likely override the air pressure limit of 2 psi. 

Response 

We agree that air agitation should be excluded. 

Comment 2 - hn Kusz (Safetv - Kleen) 

Separate the operating standards by cleaner type, as was done for the 

equipment standards. There should be four types. One of the types 

would be remote reservoirs. 

Response 

The suggestion is appropriate. The operating requirements were 

grouped by cleaner type where appropriate. 

Comment 3 - hn Kusz (Safetv - Kleen) 

The requirement for covers on some remote reservoirs may create a fire 

and safety hazard. 

Response 

Either a cover or a drain plug is acceptable for use with remote 

reservoirs using volatile solvents. Covers are not required for 

remote reservoirs using low volatility solvents. 

Comment 4 - hn KUS~ (Safetv - Kleenl 

Increase the size limit for cleaners allowed to have hinged covers to 

perhaps 5 square feet. Exempt cleaners from this requirement, if the 

freeboard ratio is greater than 2. 

Response 

Hinged covers can be used for all cold cleaners which use low 

volatility solvent, regardless of size. Remote reservoirs using low 

volatility solvent are not required to have a cover. 
Comment 5 - hn KUS~ [Safetv - Kleen! 

Use either vapor pressure or boiling point to represent volatility. 

Response 

The initial boiling point of the solvent is used to represent 

volatility. Because there is no standardized test method for vapor 

pressure, we prefer to use initial boiling of the solvent as a 

standardized criterion for volatility. 

Comment 6 - hn Kusz (Safetv - Kleen) 

In multi-constituent solvents, water and exempt solvents may be the 

first to boil; thus, representing the initial boiling point. This 

needs to be clarified. 

Response 

The determination provides methods for analysis of VOC and exempt 

compounds. The initial boiling point of the non-VOC constituents can, 

therefore, be evaluated. 

Comment 7 - ke Neil (Haloaenated Solvents Industrv Alliand 

The percent VOC exemption in solvent should be raised to about 5 to 10 

percent, to allow the use of alternative solvents. 

Response 

Raising the exemption will result in the increased emissions of VOC, 

It is not our intention to exempt significant amounts of VOC from the 

determination. Existing district rules, such as the Bay Area Air 

Quality Management District Regulation 8, Rule 16 and the South Coast 

Air Quality Management District Rule 1122, provide a 1 to 2 percent 

VOC exemption.