Technician’s Guide and Workbook for the EPA Section 608 Test Section 6: Core Part 5

Recovery Techniques Topics in this section: Need to avoid mixing refrigerants Factors affecting speed of recovery (ambient temperature, size of recycling or recovery equipment, hose length and diameter, etc.)

Need to Avoid Mixing Refrigerants Proper documentation of refrigerants being held for recycling is important. Pure recovered refrigerant is obviously the easiest and cheapest to recycle. Mixtures of refrigerants should be avoided and a best practice is to use dedicated recovery equipment that is kept separate from servicing equipment. WARNING: Some websites promote propane as a drop-in filler for R-22 systems. Propane is highly flammable and is not allowed by the EPA for use in R-22 equipment. Note: R-290 is a propane refrigerant and does not have the same chemical makeup as what is used in your propane gas grill. Bottom line: Never mix refrigerants or change the composition of refrigerant blends. Mixing new blended refrigerant into a leaking system with the same blended refrigerant will result in the ratios of the refrigerant components falling outside of the required composition parameters. Due to the possibility of uneven leakage rates (some leakage locations within a system have more impact than others) and varying refrigerant pressures at the leak point, when there has been a history of leakage the best practice is to remove all of the compromised blend for recycling and replace it with a new “virgin refrigerant” charge. Blended refrigerants must always be removed from the liquid side of the cylinder to maintain the proper mixture. However, technicians must make sure that the liquid blend has changed into a gas before it enters the compressor.

Factors Affecting Recovery Speed The following list is designed to aid in speeding up the refrigerant recovery process: First, select recovery equipment designed for high fluid flows that can handle both fluid and vapor. Remove all Schraeder valve™ cores. Start the recovery process on the liquid side, then open the vapor side after a few minutes. Recovery cylinder valves should be wide open. In fact, make sure all refrigerant valves are wide open. Use a short, large-diameter, open hose designed for removing refrigerant, connecting the recovery machine outlet to the liquid connection of the recovery cylinder. Keep recovery equipment in the shade when possible. Recovery tanks can be rotated or held in an ice bath. Note: Recovery cylinders need to be capable of holding 20% more refrigerant than the amount being recovered.

Dehydration Evacuation Topics in this section: Good evacuation practices EPA recovery requirements for reclaiming refrigerant

Good Evacuation Practices (1) Evacuation of a system that has been opened for service or component replacement is important. First, always make sure that the system will remain off during the evacuation process—operating under a vacuum can damage the compressor, so pull the fuse! When proper evacuation procedures are not followed, the introduction of moisture and other non-condensables can cause higher head pressure and dilute the ability of the oil to properly lubricate, resulting in increased operating costs and increased compressor wear and tear. For R-410A systems, moisture degrades the POE lubricant and, in addition to causing wear on the compressor, can cause clogging of the metering device. Purging (sweeping) with a dry gas (i.e., nitrogen) from the liquid-side access valve to the suction-side access valve provides proof that the system’s refrigerant path is open. A pressure test before starting the purge process using nitrogen or another dry gas is done to make sure there are no leaks, and to capture some of the moisture that can be found in any system that has been opened to the atmosphere.

Good Evacuation Practices (2) Test the vacuum pump by attaching a micron gauge to the ¼” connection to make sure it can reach 100 microns or less. Note: Remember to change the vacuum pump oil before each usage. Following proper evacuation procedures results in the removal of all non-condensables (also known as degassing) and the removal of moisture (also known as dehydration), which occurs at vacuums of 500 microns and below for refrigeration systems. Evacuation should be done to a level of 500 microns or less for a stage 1 leak test and the micron gauge should be as far away from the vacuum pump as possible (See Figure 18). A standing test is done to make sure there are no leaks; the system should remain at the 500 micron level for 10 minutes. If there is a leak, the system will keep rising in pressure until it reaches atmospheric pressure. If there is moisture present, it will rise to a higher micron value and the gauge will stop moving.

Good Evacuation Practices (3) A good vacuum pump will pull a system down to 500 microns, where the evacuation and dehydration should be complete, and a second standing test may be performed.

EPA Recovery Requirements for Reclaiming Refrigerant This section applies to the evacuation of refrigerant from appliances containing any Class I or Class II refrigerant. Starting January 1, 2019, the provisions in EPA §608 apply to all refrigerants except small appliances, MVACs, and MVAC-like appliances. Before opening appliances, or disposing of them, technicians must evacuate the refrigerant—including all the liquid refrigerant—to the levels specified in Table 3, using a recovery and/or recycling machine certified to EPA regulations. Technicians may evacuate either the entire appliance or the part to be serviced, if the refrigerant in the part can be isolated to a system receiver. A technician must verify that the applicable level of evacuation has been reached in the appliance or the part before it is opened.

Table 3 Type of appliance Inches of Hg vacuum (relative to standard atmospheric pressure of 29.9 inches Hg) Using recovery and/or recycling equipment manufactured or imported before November 15, 1993 Using recovery and/or recycling equipment manufactured or imported on or after November 15, 1993 Very-high-pressure appliance High-pressure appliance, or isolated component of such an appliance, with a full charge of less than 200 pounds of refrigerant High-pressure appliance, or isolated component of such an appliance, with a full charge of 200 pounds or more of refrigerant 4 10 Medium-pressure appliance, or isolated component of such an appliance, with a full charge of less than 200 pounds of refrigerant Medium-pressure appliance, or isolated component of such an appliance, with a full charge of 200 pounds or more of refrigerant 15 Low-pressure appliance 25 mm Hg absolute

More Directions from the EPA (1) The following three directions apply to appliance evacuation: 1. If evacuation of the appliance to the atmosphere is not to be performed after completion of the maintenance, service, or repair, and if the maintenance, service, or repair is not major as defined by the EPA, one of the following must be done: The appliance must be evacuated to a pressure no higher than 0 psig before it is opened, if it is a medium-, high- or very-high-pressure appliance.

More Directions from the EPA (2) Or, the appliance must be pressurized to a pressure no higher than 0 psig before it is opened if it is a low-pressure appliance. Persons must cover openings when isolation is not possible. Persons pressurizing low-pressure appliances that use refrigerants with boiling points at or below 85°F at 29.9 inches of mercury (standard atmospheric pressure), must not use methods such as nitrogen that require subsequent purging. Persons pressurizing low-pressure appliances that use refrigerants with boiling points above 85°F at 29.9 inches of mercury must use heat to raise the internal pressure of the appliance as much as possible, but may use nitrogen to raise the internal pressure of the appliance from the level attainable through the use of heat to atmospheric pressure. Or, for the purposes of oil changes, the appliance must be evacuated or pressurized to a pressure no higher than 5 psig before it is opened; alternatively, the oil may be drained into a system receiver to be evacuated or pressurized to a pressure no higher than 5 psig.

More Directions from the EPA (3) 2. If leaks in the appliance make evacuation to the levels in Table 3 impossible, or if they would substantially contaminate the refrigerant being recovered, persons opening or disposing of the appliance must: Isolate leaking components from non-leaking components wherever possible. And, evacuate non-leaking components to be opened or disposed of to the levels specified in Table 3. And, evacuate leaking components to be opened or disposed of to the lowest level that can be attained without substantially contaminating the refrigerant. This level may not exceed 0 psig.

More Directions from the EPA (4) 3. Recordkeeping. Technicians evacuating refrigerant from appliances with a full charge of more than 5 and less than 50 pounds of refrigerant for purposes of disposal must keep records documenting the following for three years: The company name, location of the appliance, date of recovery, and type of refrigerant recovered for each appliance. And, the total quantity of refrigerant, by type, recovered from all disposed appliances in each calendar month. And, the quantity of refrigerant, by type, transferred for reclamation and/or destruction, the person to whom it was transferred, and the date of transfer.

Safety Topics in this section are: Risks of exposure to refrigerant and personal protective equipment Reusable (or "recovery") cylinders versus disposable cylinders (ensure former Department of Transportation [DOT] approved, know former's yellow and gray color code, never refill latter) Risks of filling cylinders more than 80 percent full Use of nitrogen rather than oxygen or compressed air for leak detection Use of pressure regulator and relief valve with nitrogen

Risks of Exposure to Refrigerant and Personal Protective Equipment (1) Working with refrigerants can be hazardous; safety precautions must be taken to protect yourself and others. Refrigerant characteristics that require special precautions are as follows. Exposure: When exposed to the atmosphere, liquid refrigerant boils at extremely low temperatures. If this liquid comes in contact with your skin or eyes, you could suffer frostbite. Protect your eyes—they are the only ones you get!—using safety glasses or goggles. Lined rubber gloves are recommended to protect your hands, while long pants and long-sleeved shirts are a good idea for arm and leg protection. Pressure: Any gas under high pressure is hazardous. Refrigerant that is under pressure can vent rapidly from a system or cylinder, and the velocity of the escaping gas can damage skin and eyes. Blowing dust and dirt can aggravate the situation; always wear safety goggles to protect your eyes. To prevent pressure from building to an unsafe level, a pressure relief device must protect every refrigeration system.

Risks of Exposure to Refrigerant and Personal Protective Equipment (2) Suffocation: Refrigerants can cause suffocation via oxygen deprivation. Almost all refrigerants are heavier than air and, if vented, will collect near the floor of a mechanical room. Oxygen is displaced as the refrigerant settles. If a large enough quantity is released, you could suffocate because you’re breathing refrigerant and aren’t getting enough oxygen. This hazard is less likely with small appliances because of their smaller refrigerant charges. However, you should be aware that the hazard exists and know how to protect yourself and others. If a large leak does occur, you can use a self-contained breathing apparatus (SCBA) for air, if one is available at that particular facility, which is a bottle of air similar to those worn by firemen. If an SCBA is not available, or if you don’t know how to properly use one, you should immediately leave the area. These precautions go for anyone in the area, whether or not they are working with you. If you know of a leak, sound the alarm! Once everybody is safely out, the area should be ventilated to remove the refrigerant.

Risks of Exposure to Refrigerant and Personal Protective Equipment (3) Suffocation: Refrigerants can cause suffocation via oxygen deprivation. Almost all refrigerants are heavier than air and, if vented, will collect near the floor of a mechanical room. Oxygen is displaced as the refrigerant settles. If a large enough quantity is released, you could suffocate because you’re breathing refrigerant and aren’t getting enough oxygen. This hazard is less likely with small appliances because of their smaller refrigerant charges. However, you should be aware that the hazard exists and know how to protect yourself and others. If a large leak does occur, you can use a self-contained breathing apparatus (SCBA) for air, if one is available at that particular facility, which is a bottle of air similar to those worn by firemen. If an SCBA is not available, or if you don’t know how to properly use one, you should immediately leave the area. These precautions go for anyone in the area, whether or not they are working with you. If you know of a leak, sound the alarm! Once everybody is safely out, the area should be ventilated to remove the refrigerant.

Risks of Exposure to Refrigerant and Personal Protective Equipment (4) Toxicity: Some refrigerants, such as ammonia, are highly toxic, while others are considered non-toxic at concentrations below specified exposure limits. An exposure limit is a concentration, usually expressed in parts per million (ppm), that sets an upper safe limit of exposure to a chemical in the surrounding air. The Threshold Limit Value - Time Weighted Average (TLV-TWA) is a common exposure limit. Technicians should review Safety Data Sheets (SDS) for the refrigerants they are using. People exposed to concentrations below the exposure limits do not suffer any adverse affects due to the chemical. However, inhaling higher concentrations of refrigerant vapors can cause heart irregularities or unconsciousness. The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) has developed a numbering scheme to designate refrigerant safety.

Risks of Exposure to Refrigerant and Personal Protective Equipment (5) Acids and harmful gas: Acids and other harmful gases can be created if refrigerants are exposed to high temperatures. For example, open flames from soldering , or hot metal surfaces from compressor burnouts can cause refrigerants to decompose and form hydrochloric (from chlorine) and hydrofluoric (from fluorine) acids and phosgene gas. The acids are corrosive, contaminate the system oil and require that the oil be flushed from the system. Phosgene is colorless and highly toxic if it is breathed in; it has been used as a warfare poison gas. When soldering, it is necessary to evacuate the portion of the system that is being worked on. This will prevent the soldering heat from forming these hazardous materials within the system.

ASHRAE 34 Limits For Toxicity (poisonous or chemically dangerous) Class A signifies refrigerants for which toxicity has not been identified at concentrations less than or equal to 400 ppm. Class B signifies refrigerants for which there is evidence of toxicity at concentrations below 400 ppm.

ASHRAE 34 Limits For Flammability (ease of innition) Class 1 indicates refrigerants that do not show flame propagation when tested in air at 21°C and 101 kPa. Class 2L indicates a lower burning velocity. Class 2S indicates a burning velocity less than 10 cm/s (3.9in/s). Class 2 indicates refrigerants having a lower flammability limit of more than 0.10 kg/m3 at 21°C and 101 kPa and a heat of combustion of less than 19 kJ/kg. Class 3 indicates refrigerants that are highly flammable, as defined by a lower flammability limit of less than or equal to 0.10 kg/m3 at 21°C and 101 kPa or a heat of combustion greater than or equal to 19 kJ/kg.

ASHRAE 34 Table ASHRAE 34 Safety Groups Toxicity Flammability in Air The Table below shows the toxicity and flammability rating systems combined. For example, “B1” designates higher toxicity with no flammability, and “A3” designates lower toxicity with higher flammability. Note: Equipment containing flammable refrigerant must have the refrigerant tubing colored red and be marked with the “1.0” designation. ASHRAE 34 Safety Groups   Toxicity Flammability in Air Lower Higher A3 B3 A2 B2 A2L B2L None A1 B1

Reusable (or “recovery”) Cylinders vs Disposable Cylinders (1) There are basically three types of refrigerant cylinders: storage, disposable, and service (also called refillable or reusable). Storage cylinders are typically used only for storing large amounts of refrigerant that can be transferred to smaller refillable cylinders for transportation to the job site Refrigerant cylinders are color coded according to the type of refrigerant contained for easy identification.

Reusable (or “recovery”) Cylinders vs Disposable Cylinders (2) Reusable (refillable) cylinders or containers used for recovery and transporting refrigerant under pressure must meet Department of Transportation (DOT) safety requirements and must carry a DOT refillable designation. Recovery (refillable/reusable) cylinders are painted with a gray body and yellow top. DOT requires proper DOT classification tags on all cylinders including a refrigerant label to identify the type of refrigerant in the cylinder . The DOT also requires the number of cylinders to be stated on the shipping label.

Reusable (or “recovery”) Cylinders vs Disposable Cylinders (3) Disposable cylinders: It is a violation to refill disposable cylinders. These are one-time cylinders – designated as “DOT Specification 39 non-reusable (non-refillable) cylinders” – used to deliver virgin refrigerant. Once emptied, they must be discarded; verify that there is no refrigerant left by reducing the internal pressure to at least 0 psig. The cylinder should then be rendered useless to prevent anyone from refilling it. Finally, the cylinder metal should be recycled. All cylinders should be stored and shipped in a secure and upright manner.

Risks of Filling Cylinders More than 80% Full Pressurized refrigerant cylinders can explode if overfilled. It is crucial that you follow the 80% fill rule. Never fill a cylinder more than 80% of its liquid level. This requirement permits for space at the top of the tank for expanding gas when the temperature in the bottle rises due to high ambient temperatures (say, in the back of the truck under a grueling sun).

Use of Nitrogen for Leak Detection Nitrogen used to pressurize a system or to blow debris out of the system is delivered in bottles that are under extremely high pressure. This pressure is around 2000 psi and is high enough to damage coils and other components in a system. Always use a pressure regulator on a nitrogen bottle, or any high- pressure gas, to reduce the usable pressure. Always include a pressure relief valve in case the pressure regulator fails. Pressure relief valves must not be installed in series.