New users of vapor degreasers and others who want to meet the EPA and/or regional emissions control regulations are often confused. There is much misinformation, rumors and a lack of easy access to the authoritative facts regarding the halogenated solvent NESHAPS (National Emission Standards for Hazardous Pollutants). THE NESHAPS are the basis for all states' and regions' emissions control regulations. Some states have added tougher standards than the EPA requires.

We will try to answer the following questions.

1. What does a new vapor degreaser user need to do to be compliant?
2. What solvents are OK?
3. Which government agencies does a user need to placate?

EPA's NESHAPS REGULATION 12/2/1994
What is this regulation?
On December 2, 1994, the Environmental Protection Agency (EPA) published the National Emission Standards for Hazardous Air Pollutants " for Halogenated Solvent Cleaning (59 CFR 61801). The law falls under the authority of Section 112 of the 1990 Clean Air Act Amendments. You can find the regulation in 40 Code of Federal Regulations Part 63, Subpart T.
The regulation focuses on "reducing the emissions of selected halogenated solvents used in parts cleaning. The compliance methods center around best operating practices and pollution prevention techniques.

Who and what is covered?
Owners and operators of degreasers using the following chlorinated solvents: methylene chloride; perchloroethylene; 111 trichloroethane; trichloroethylene; chloroform; carbon tetrachloride. Suspected ozone depleting solvents like freon, 111 trichloroethlene, carbon tetrachloride, chloroform and some others are severely restricted under other Clean Air provisions.
Note: Blended cleaning solvents must contain a total regulated solvent content below 5 percent by weight to be exempted from regulation. To . determine the solvent content, contact your vendor, use your Material Safety Data Sheets, or use EPA Test Method 18.

Navigating the Regulations
The regulation seeks to reduce emissions of the six halogenated cleaners listed in the beginning through better operating practices and pollution prevention techniques. As a result; the law offers several compliance techniques.

Your responsibilities for each technique vary depending on your degreaser. The regu1ation categorizes degreasers in two classes based on machine type: batch vapor and in-line cleaners. See Figures 2 through 6 for examples of each machine.
EPA classifies batch vapor degreasers in two sizes, small and large, based on the machine's solvent/air interface area. Small batch degreasers have a solvent/air interface area less than or equal to 13 ft2 (1.21 m2). Large degreasers have an interface area greater than 13 ft2.
In-line degreasers are either existing or new. They can use either a cold or vapor process to clean parts. Existing in-line degreasers are those for which construction, or reconstruction, began on or before November 29, 1993. EPA classifies all others degreasers as new.
Three primary methods exist for regulatory compliance: Control combinations; Alternative standards. The specifics of each method depend on your machine type. Carefully consider your operation before making a decision; then choose the method that best fits your situation. Here's a brief overview of each method.
Control combinations: You may choose combinations of control technologies to reduce solvent releases. Your type of degreaser determines which group of control combinations you use. A set of minimum equipment design standards and operation practices accompany this method. Your reporting and monitoring requirements also depend on which group you choose.

Idling emission standards: This technique combines the minimum equipment design and operating practices with emission limits. You may use additional controls and techniques to meet the limits.

Alternative standards: You reach compliance with this method by meeting halogenated solvent emission limits from each machine as calculated on a three-month rolling average basis. You can use any means necessary to meet the emission limits. However, you might need to adopt several pollution prevention techniques to obtain compliance.

Note. EPA allows another route to compliance - the equivalent methods of control. Under it, you can develop your own techniques, using either equipment or workplace practices, to meet compliance. However EPA or your local air authority must approve your procedures. Your application must include a complete description of the equipment or procedure; the proposed equivalency testing procedure; and the date, time and location for the equivalency demonstration. Because every situation is unique, this method is not covered in this manual. Submit the application to your regional office, or contact your local air authority for more information. The state Small Business Assistance Program can assist you in submitting your application.

Compliance Methods

TABLE 2 REQUIRED ELEMENTS FOR EACH COMPLIANCE METHOD

Control Combinations Method

This method requires three items to meet compliance: using a degreaser that meets a minimum equipment design, adopting mandated operating practices, and using a group of control technologies. Equipment design and operating practices lay the groundwork for reducing emissions. Using a combination of controls helps further minimize your solvent emissions. One appealing characteristic of this method is that it has no emission limits. You are only responsible for using a control group and meeting performance and administrative requirements.

EPA uses seven technologies to make up the control combinations. The combinations consist of either two or three control technologies depending on your degreaser. The technologies range from simple and inexpensive to complex and costly. The seven controls EPA used to create the combinations include:

. Working mode cover . Dwell time

. Freeboard refrigeration . Reduced room draft

. Carbon adsorber . Freeboard ratio of 1.0

. Superheated vapor

Some machine types have more control combinations available. The different combinations give you flexibility in picking a compliance method.

Idling Emissions

Emission limits are the basis of this method. The emission rate depends on the machine, and as with the control combinations method, you must use the minimum equipment designs and operational practices prescribed by EPA. However, you can use any additional techniques (controls or operating procedures) to meet the limits. But, you must inform EPA of your method and a procedure to monitor its performance.

Alternative Standards
Like idling emissions, this method is emissions based. However, this method has no equipment or operational requirements. The only requirement is that solvent emissions, based on a three-month rolling average, be kept below certain limits. The machine type determines these limits. Meeting the emission limits may prove challenging to owners and operators of large degreasers.
DETAILS OF CONTROL COMBINATIONS
As mentioned, the control combination method consists of three items to meet compliance:
Installing controls to meet a minimum design requirement;
Adopting certain operating practices;
Using a predefined group of control technologies.
To meet compliance, first, you should meet the required equipment design. Next, train your workers to use the prescribed workplace practices. After implementing workplace practices, choose a control combination and establish a monitoring program to ensure their proper operation. Next, develop a recordkeeping system to track the control's performance. Finally, report the required information to EPA on time.
Minimum Equipment Design
This section describes the minimum design features your degreaser must have. These requirements apply to both classes of batch vapor and in-line degreasers. New machines may have the equipment in place, while older models may need retrofitting. If your machine already has the equipment, ensure that it can meet performance requirements. These are EPA's requirements:
An idling and down time mode cover or reduced room draft;
A freeboard ration of at least 0.75;
An automated parts handling system that moves parts slower than 11 feet per minute (3.4 meters per minute) during the entire cleaning cycle (for example, parts loading through removal);
An automatic shut-off for the sump heater when the solvent level drops to the sump heater coils;
A vapor level control device that shuts off sump heat if the vapor level rises above the primary condenser;
A primary condenser above the vapor zone;
A carbon adsorber if a lip exhaust is used to collect solvent r vapors.
NOTE: There are monitoring and record keeping requirements if you use a hoist.
Required Workplace Practices

In addition to the minimum equipment design, EPA requires that users choosing this compliance route adopt certain workplace practices which center around pollution prevention. This list suggests ways to reduce solvent loss, regardless of your compliance method:
Minimize air flow across the opening of the degreaser by covering it during idling and downtime or reducing room draft;
Operate open-top batch vapor cleaning machines so the size of parts or part baskets to less than 50 percent of the machine's solvent/air interface or reduce the entry speed of the parts or part baskets into the degreaser to less than 3 feet per minute (0.9 meters per minute);
Conduct spraying operations within the degreaser ideally, spray within the vapor zone or in a baffled or enclosed area within the machine;
Place parts so they do not capture or trap solvent-for example, orient parts with cavities down to prevent solvent accumulation. Tip or rotate parts to remove excess solvent trapped in recessed cavities or in blind holes;
Allow parts baskets or parts to stop dripping before removing from the degreaser;
Turn on the primary condenser before starting the sump heater;
Turn off the primary condenser after turning off the sump heater and the solvent vapor layer has collapsed;
Use threaded or other leakproof couplings while adding or removing solvent from any degreaser. Also, place inlets to the solvent sump below the liquid solvent level;
Follow manufacturers' recommendations for maintaining each degreaser and its controls. The EPA must approve any alternative maintenance practice;
Ensure that all degreaser operators can pass the appropriate sections of EPA's written test (see Appendix E). An inspector may request that degreaser operators take the test during an inspection;
Collect and store all waste solvent, still bottoms, and sump bottoms In closed containers. The containers may allow for pressure relief, but liquid solvent should not drain from the container;
Avoid cleaning sponges, fabric, wood, and paper products in a degreaser.

Available Control Combinations
This section presents the control combinations you may use. As mentioned, no emission limit exists with this compliance method. However, properly using each control group will reduce halogenated solvent emissions.
You must know two characteristics of your degreaser to ensure that you pick from the correct pool of control groups. First, know whether you have a batch vapor or in-line degreaser. Second, if you use a batch degreaser, you should know its solvent/air interface area. This is the surface area where the solvent condensate meets the air. If you use an in-line machine, you need to know whether EPA considers it new or existing.
Appendix F contains forms to help you track the parameters that require monitoring. The forms provide guidance only and may not apply to your specific situation.

Tables 3 through 6 provide a matrix of the control options available for each degreaser classification. The tables should help you identify the technologies contained in each control group. Following the tables, you will find details of each control technology, including operating and monitoring requirements.

Compliance Methods

Freeboard refrigeration devices
A freeboard refrigeration device (also called a chiller) is a set of condenser coils in the freeboard region that creates a chilled air blanket to condense the solvent vapor and prevents its escape.

The freeboard refrigeration device must create a cool air zone which is 30 percent or less of the solvent's boiling point. For example, if your solvent boils at 100° F, your freeboard refrigeration device must cool the air blanket to 30° F or less. Table 7 lists the minimum temperatures needed for pure solvents.

Temperature Requirements For Freeboard Refrigeration Devices For Regulated Solvents
Solvent Boil Temp. Required Blanket Air Temp.
Methylene Chloride 104 F 31.2 F
Trichloroethylene 189 F 56.7 F
Perchloroethylene 250 F 75 F

If you use a blended cleaning solution of regulated halogenated solvents and other chemicals, use the boiling point provided by the manufacturer on the material safety data sheets.

Check and record the temperature of the chilled region weekly using a thermometer or thermocouple. Measure the temperature in the center of the air blanket while the machine is idling.

Freeboard ratio of 1.0
The freeboard ratio is the freeboard height divided by the smaller interior dimension (length, width, or diameter) of the degreaser. For batch cleaners, the freeboard height is the distance from the solvent/air interface to the top of the idling degreaser. Freeboard height on in-line machines is the distance from the solvent/air interface to the bottom of either the entrance or exit, whichever is lower. Figures 2 through 6 show the freeboard region for both batch vapor and in-line degreasers respectively.

Superheated Vapor
Superheated vapor degreasers heat the solvent vapor above its boiling point to facilitate parts drying and minimize solvent drag-out.

Degreasers equipped with superheated vapor devices must:

. Maintain the solvent vapor at least 10° F above the solvent's boiling point;

. Use the manufacturer's method for determining the dwell time in the superheated vapor zone;

. Ensure the parts remain in the superheated vapor zone for the entire dwell time;

Place parts so they do not capture or trap solvent-for example, orient parts with cavities down to prevent solvent accumulation. Tip or rotate parts to remove excess solvent

Dwell Time
Dwell time is the time parts are held in the freeboard area so that some residual solvent may drain back into the degreaser. This technique reduces solvent drag-out and evaporative losses. Each part will require different dwell times due to its shape and material. As a result, you must determine the dwell time for every unique part you clean if you use this control method.

EPA has developed a procedure to determine the proper dwell time:

1. Use parts or parts baskets that are at room temperature.

2. Clean parts in the degreaser per standard operating procedures.

3. Determine the time for the part(s) or parts basket to cease dripping once placed in the freeboard region.

4. The proper dwell time for parts to remain in the freeboard area is no less than 35 percent of the time determined in step 3.

Example
Plant XYZ separately cleans two parts, A and B, in an open-top batch vapor degreaser using methylene chloride. To obtain compliance, XYZ chooses a control combination that uses dwell time. Thus, the company must determine the proper dwell time for each part type or parts basket. First, XYZ must clean parts A, which are at room temperature, in the vapor degreaser. After the cleaning cycle, an operator places the wet parts into the freeboard area and star1s a timer. When the parts stop dripping, the operator stops the timer. The elapsed time (for example, 10 minutes) is multiplied by 35 percent to determine the proper dwell time.

Proper dwell time = 10 minutes x 35 percent = 3.5 minutes

Thus, the proper dwell time for A parts is 3.5 minutes. This is the minimum time the parts must remain in "dwell." The same procedure is repeated for B parts. If XYZ decides to clean both parts A and B together, they must use the longer dwell time.

Important information about dwell time:

. Document the test used to determine dwell time;
. Measure dwell time monthly to assure you're using the proper time.

Reduced Room Draft

"Reduced room draft" is a method to decrease the air flow across the freeboard area. This minimizes turbulence inside the degreaser. Two methods for reducing room draft are controlling room parameters (i.e., redirecting fans, closing doors and windows, etc.), or either fully or partially enclosing the degreaser. Whatever technique you choose, you must keep the air flow across the freeboard area ill inside the machine to less than 50 ft/min (15.2 m/min). EPA developed the following procedures for each method to determine the air velocity:

Controlling room parameters
. Determine maximum wind speed with an air velocity meter on each of the four corners of the degreaser. Measure the windspeed within 6 inches above the freeboard area;

. Record the maximum reading for each corner;

. Average the values obtained at each corner to determine the average wind speed;

. Lower the velocity if the average wind speed is greater than 50 ft/ min. (for example, redirecting fans);

. Monitor weekly the room parameters established during the initial compliance test to achieve the reduced room draft of less than 50 ft/min.

Enclosures
. Determine the maximum wind speed inside the enclosure with an air velocity meter;

. On a monthly basis:

Monitor the air flow inside the enclosure;

Inspect the enclosure for cracks, holes, and/or other defects.

Carbon Adsorbers

Carbon adsorption is a method of controlling solvent emissions by passing the exhaust from a degreaser through activated carbon. EPA discourages this method because it is a treatment technology. In addition, carbon adsorption can produce other potentially hazardous waste streams, like spent carbon beds saturated with halogenated solvent. As a result, additional waste management costs can occur. You should consider all factors and options before using this control technology.

The allowable limit for the solvent concentration in the carbon adsorber exhaust is 100 parts per million (ppm) by volume. If the concentration exceeds 100 ppm, adjust the desorption schedule, or replace the carbon bed if it is not a regenerative system. Additional operating requirements include:

. Ensuring that the carbon adsorber bed is not bypassed during desorption;

. Locating the lip exhaust so the degreaser's cover closes below the lip exhaust level.

With this control you must measure and record the solvent concentration in the exhaust of the carbon adsorber weekly. Test the concentration with a colorimetric detector tube. The measurement procedure should meet the following criteria:

Sample gas at the exhaust vent of the solvent cleaning machine;

. Ensure that the vapor degreaser is in working mode and venting to the carbon adsorber;

. Be sure the colorimetric detector tube is accurate to +/- 25 parts per million by volume;

. Follow the manufacturer's instructions when using the colorimetric detector tube;

. Provide a sampling port for monitoring within the exhaust outlet of the carbon adsorber. The port should be at least 8 stack or duct diameters downstream from any flow disturbance such as a bend, expansion, contraction, or outlet; downstream from no other inlet; and 2 stack or duct diameters upstream from any flow disturbance such as a bend, expansion, contraction, inlet or outlet.

Covers
Covers keep the solvent vapors inside the degreaser by protecting its openings from air movements. Many different covers exist for use including rolltop, sliding, and biparting. Covering a degreaser is one of the cheapest and easiest ways to reduce solvent losses.

Covers for a degreaser can be independent or part of its design. Any cover must seal the cleaner and prevent solvent vapors from escaping. When using a cover, you must inspect it monthly for cracks and to ensure proper operation. EPA recognizes three types of cover: idle, working, and downtime-mode:

Idling-mode cover: any cover that shields the degreaser openings during the idling mode. You can use an idling-mode cover as a working-mode cover if that definition is also met.

Working-mode cover: any cover that protects the degreaser openings from outside air disturbances during pans cleaning. Working mode covers are opened only during pans entry and removal. You can also use a cover that meets this definition as an idling-mode cover if that definition is also met.

Downtime-mode cover: a cover used when the degreaser is off. It must completely cover the openings of the degreaser

Hoists
A hoist is not an available control method in a control combination. It's required per the mandatory equipment design. The following monitoring and reporting requirements are associated with hoist use:

. Calculate hoist speed by measuring the time it takes for the hoist to travel a measured distance and report it in meters per minute. To convert from feet to meters, multiply the distance in feet by 0.305;

. Check the hoist speed monthly unless:

hoist speed does not exceed 11 feet/minute for one year. If so, you may measure hoist speed quarterly;

you can demonstrate that hoist speed cannot exceed 11 feet/ minute. Then you can measure the speed quarterly.

DETAILS OF THE IDLING EMISSIONS METHOD
This method has a limit on the quantity of regulated solvents emitted from the degreaser while the machine is idling. Figure 7 shows the steps required to meet compliance with this method. Table 8 lists the emission limits for each regulated degreaser.

TABLE 8 IDLING EMISSION RATES FOR EACH DEGREASER TYPE

Degreaser type Idling emission rate (lbs/hr/ft2)

Small and large batch .045

I Existing and new in-line .021

Although this regulatory method is emissions oriented, it still requires the minimum equipment design and operational methods used in the control combinations method. If these techniques do not lower your emissions, you may use any additional controls or procedures necessary to meet the limit.

Your emission limit depends on the area of the degreaser's solvent/air interface. Once you determine the area, multiplying it by the appropriate emission factor gives the maximum hourly emission rate of solvent that the degreaser may emit.

NESHAP (11/10/03) for Halogenated Solvent Cleaning

The EPA released a final ruling concerning The National Emission Standards for Hazardous Air Pollutants (NESHAP) for Halogenated Solvent Cleaning (40 CPR part 63, subpart T), which was proposed on November 29,1993,promulgated on December 2, 1994, and corrected to final rule June 5, 1995.This rule became effective November 10, 2003.

Plants must demonstrate compliance with the emission standards by monitoring their control devices and performing annual emissions testing. This information notifies the EPA when a source becomes subject to the regulations, informs the Agency if a source is in compliance when it begins operation, and informs the Agency if the source remained in compliance during any period of operation.

In the Administrator's judgment, emissions of hazardous air pollutants (HAPs) from halogenated solvent cleaners may cause or contribute to air pollution that may reasonably be anticipated to endanger public health or welfare. Therefore, NESHAP standards were promulgated for this source category, as required under section 112 of the Clean Air Act. HAP emissions from halogenated solvent cleaners are the result of inadequate equipment design and work practices.

These standards rely on the proper design and operation of halogenated solvent cleaning machines such as working-mode covers, a freeboard ratio of 1.0, and reduced room draft to reduce solvent emissions from halogenated solvent cleaners. Certain records and reports are necessary to enable the EPA to identify sources subject to the standards and to ensure that the standards are being achieved.

Owners/operators of halogenated solvent cleaners must provide the EPA with an initial notification of existing or new cleaning machines, initial statements of compliance, an annual control device monitoring report (owners/operators of batch vapor and in-line cleaning machines complying with the alternative standard), and exceedance of monitoring parameters or emissions.

The records that the facilities maintain indicate to the EPA whether they are operating and maintaining the halogenated solvent cleaners properly to control emissions. In order to ensure compliance with the standards promulgated to protect public health, adequate reporting and record keeping is necessary. In the absence of such information, enforcement personnel would be unable to determine whether the standards are being met on a continuous basis, as required by the Clean Air Act.

The annual public reporting and record keeping burden for this collection of information are estimated to average 14 hours per response. Burden means the total time, effort, or financial resources expended by persons to generate, maintain, retain or disclose or provide information to or for a Federal agency. This includes the time needed to review instructions; develop, acquire, install, and use technology and systems for the purpose of collecting, validating and verifying information, processing and maintaining information, and disclosing and providing information; adjust the existing ways to comply with any previously applicable instructions and requirements; search data sources; complete and review the collection of information; and transmit or otherwise disclose the information.