Governmental Regulations

THE CLEAN AIR ACT 1990-SECTION 609

Our Threatened Ozone Layer

The ozone layer acts as a blanket in the stratosphere that protects us from harmful Ultra Violet (UV) radiation. Scientists worldwide believe that man-made chemicals such as CFC-12 (also known by the trade name Freon) are rapidly destroying this layer of gas 10-30 miles (16-48 km) above the earth's surface. Strong UV radiation breaks the CFC-12 molecules apart, releasing chlorine. A single chlorine atom can destroy over one hundred thousand ozone molecules. Ozone loss in the atmosphere is likely to lead to an increase in cataracts and skin cancer, which is now one of the fastest growing forms of cancer, and could weaken the human immune system. In the U.S., one person dies of skin cancer every hour. Agriculture, as well as plant and animal life, may also be dramatically affected.

Remember that ozone is "good up high, bad nearby": even though it protects us when it is in the stratosphere, ozone at ground level can be harmful to breathe and is a prime ingredient in smog. Many man-made sources such as tailpipe emissions from vehicles contribute to ground-level ozone.

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Global Action to Protect the Ozone Layer

The United States has joined over 160 countries as a party to the international treaty known as the Montreal Protocol. All developed countries agreed to phase out production of most ozone-depleting substances, including CFC's, by the end of 1995. The 1990 Clean Air Act Amendments (the Act) incorporated this production ban date and directed the EPA to develop regulations to maximize recycling, ban nonessential uses, develop labeling requirements and examine safe alternatives for ozone-depleting substances.

Impact of Motor Vehicle Air Conditioners

One of the largest uses of CFC-12 in the U.S. is as a refrigerant in Motor Vehicle Air Conditioners (MVACs). Section 609 of the Act gives the EPA the authority to establish requirements to prevent the release of refrigerants during the servicing of MVACs and to require recycling of refrigerants. Widespread refrigerant recycling reduces the demand for virgin CFC-12 and thus extends the time that it will be available. The following sections describe the requirements of the law and its potential impact on the service industry.

Handling CFC-12

VENTING

Another section of the Clean Air Act, section 608, prohibits releasing CFC-12 into the atmosphere. The prohibition on venting CFC-12 has been in effect since 1992.

SECTION 609 REGULATORY HISTORY

The original regulation promulgated under section 609 was published in July 1992. That regulation established standards for equipment that recovers and recycles CFC-12 refrigerant from motor vehicle air conditioners, rules for training and testing technicians to handle this equipment, and record-keeping requirements for service facilities and for refrigerant retailers. A supplemental final rule published in May 1995 established a standard for equipment that recovers but does not recycle CFC-12, as well as training and testing technicians to handle this equipment.

APPROVED EQUIPMENT

Technicians repairing or servicing CFC-12 MVACs must use either recover/recycle or recover-only equipment approved by the EPA. Recover/recycle equipment cleans the refrigerant so that oil, air and moisture contaminants reach acceptably low levels. A list of approved recover/recycle and recover-only equipment is available from the EPA.

TECHNICIAN TRAINING AND CERTIFICATION

Technicians who repair or service CFC-12 motor vehicle air conditioners must be trained and certified by an EPA-approved organization. Training programs must include information on the proper use of equipment, the regulatory requirements, the importance of refrigerant recovery, and the effects of ozone depletion. To be certified, technicians must pass a test demonstrating their knowledge in these areas. A list of approved testing programs is available from the EPA.

RECORDKEEPING REQUIREMENTS

Service shops must certify to the EPA that they own approved CFC-12 equipment. If refrigerant is recovered and sent to a reclamation facility, the name and address of that facility must be kept on file.

SALES RESTRICTIONS

Section 609 has long prohibited the sale of small cans of ozone-depleting refrigerants to anyone other than a certified technician. The sale of any size container of CFC-12 to anyone other than certified technicians was prohibited under section 608 of the Act beginning on November 14, 1994. This provision is intended to discourage "do-it-yourselfers" who recharge their own air conditioners. Such individuals often release refrigerant because they typically do not have access to recovery/recycling equipment. The EPA encourages "do-it-yourselfers" to bring their vehicles to certified technicians who can properly fix air conditioners using approved equipment. This avoids damage to A/C equipment by improper charging and helps to protect the environment.

Fig. 2: Common recovery machine used on R-134a systems

Handling HFC-134a Refrigerant

VENTING

Section 608 of the Clean Air Act prohibits releasing HFC-134a into the atmosphere. The prohibition on venting HFC-134a has been in effect since November 1995.

SECTION 609 REGULATORY HISTORY

In March 1996, the EPA proposed a rule to require recycling of HFC-134a. The rule proposed standards for recover-only and recover/recycle equipment and rules for training and testing technicians to handle this equipment.

APPROVED EQUIPMENT

Because of the venting prohibition described above, technicians who repair or service HFC-134a MVACs must recover the refrigerant. Any equipment may be used to recover the refrigerant, since equipment standards will not be in place until the effective date of the final rule. Technicians are not required to recycle HFC-134a refrigerant until the effective date of the final rule. At that time, technicians handling HFC-134a will have to either recycle the used HFC-134a refrigerant on-site, or send it to an off-site reclamation facility to be purified to ARI Standard 700, before it can be used to recharge A/C equipment.

After the effective date of the rule, the EPA will make available a list of approved recover/recycle and recover-only HFC-134a equipment.

CONVERTING CFC-12 EQUIPMENT FOR USE WITH HFC-134A

EPA regulations prohibit technicians from changing fittings on the same unit back and forth so that the unit is used for CFC-12 in the morning, HFC-134a in the afternoon, then back to CFC-12 again, etc.

EPA regulations specify that when equipment is converted for use with a new refrigerant, the converted unit must be able to meet the applicable equipment standard set forth in the regulations. CFC-12 equipment may be permanently converted for use with HFC-134a under certain conditions. The EPA intends to issue regulations placing certain restrictions on these retrofits in the future. Those restrictions may require that the manufacturer's service representative rather than the automotive service technician perform the retrofit, that a unit may only be retrofitted if retrofit procedures have been certified by an independent testing laboratory such as Underwriters Laboratories, and that an appropriate label is affixed to the unit. In addition, the retrofitted unit must meet the technical specifications of SAE standard J2210 and must have the capacity to purify used refrigerant to SAE standard J2099 for safe and direct return to the air conditioner following repairs.

In the absence of any EPA regulations, a service facility may perform such a retrofit, or may have the equipment manufacturer's service representative perform the retrofit, as long as the fittings are changed in accordance with the EPA's Significant New Alternative Policy (SNAP) program regulations. The Agency cautions technicians, however, that although recovering a given refrigerant using permanently converted equipment is legal, it may not be technically desirable. The equipment is designed to be compatible with specific refrigerants, and incompatible materials may cause short circuits, damage to seals, and compressor failure. Technicians should check with the recovery equipment manufacturer for recommendations about the recovery of refrigerants other than the refrigerant the equipment was originally intended to recover. Conversion of recovery equipment for use with other refrigerants may also invalidate any warranties offered by the equipment manufacturer.

TECHNICIAN TRAINING AND CERTIFICATION

Before the final rule is published and goes into effect, technicians repairing or servicing HFC-134a MVACs do not need to be trained and certified to handle HFC-134a. After the effective date of the rule, however, technicians who repair or service HFC-134a MVACs must be trained and certified by an EPA-approved organization. If a technician is already trained and certified to handle CFC-12, he will not need to be re certified to handle HFC-134a.

RECORDKEEPING REQUIREMENTS

Service shops must certify to the EPA that they own approved HFC-134a equipment.

NOTE: This certification is a one-time requirement, so that if a shop purchased a piece of CFC-12 recycling equipment in the past, and sent the certification to the EPA, the shop does not need to send a second certification to the EPA when it purchases a second piece of equipment, no matter what refrigerant that equipment is designed to handle. If refrigerant is recovered and sent to a reclamation facility, the shop must retain the name and address of that reclaimer.

SALES RESTRICTIONS

At the time of publishing, there is no restriction on the sale of HFC-134a, so anyone may purchase it. The EPA will issue a proposed rule under section 608 of the Act that will include a proposal to restrict the sale of HFC-134a so that only technicians certified under sections 608 and 609 may purchase it. After the proposed rule is published, the EPA will review comments from the public on the proposal and will then publish a final rule sometime in late 1998.

Handling Other Refrigerants that Substitute for CFC-12

VENTING SUBSTITUTE REFRIGERANTS

Other than HFC-134a, all EPA-accepted refrigerants that substitute for CFC-12 in motor vehicles, and that are currently on the market, are blends that contain ozone-depleting HCFC's such as R-22, R-142b and R-124. Section 608 of the Clean Air Act prohibits venting any of these new blend substitutes into the atmosphere. The prohibition on venting these ozone-depleting blends has been in effect since 1992.

SECTION 609 REGULATORY HISTORY

When the March 1996 proposed rule that requires recycling of HFC-134a was published in final form in the summer of 1997, it also established a standard for equipment that is designed to recover, but not recycle, any single, specific blend substitute refrigerant.

RECOVER ONLY EQUIPMENT

Technicians recovering these blend refrigerants must use EPA-approved equipment. As noted above, the final rule contains a standard for equipment designed to recover, but not recycle, a single, specific blend refrigerant. It may be possible to convert a piece of CFC-12 recover-only equipment so that it meets this standard-see the discussion on equipment conversions that follows this topic.

The EPA is currently working with independent testing laboratories and with equipment manufacturers to devise equipment that can recover, but not recycle, not only multiple blend refrigerants, but also contaminated CFC-12 and HFC-134a. Within the next year, the EPA will propose a standard for this type of equipment. The EPA expects that this equipment should be available by the 1998 A/C season.

CONVERTING CFC-12 RECOVER-ONLY EQUIPMENT FOR USE WITH BLEND SUBSTITUTES

The EPA regulations prohibit technicians from changing fittings on the same unit back and forth so that the unit is used for CFC-12 in the morning, a blend substitute in the afternoon, another blend substitute the next morning, HFC-134a the next afternoon, etc.

The EPA regulations specify that when equipment is converted for use with a refrigerant other than the refrigerant for which the equipment was originally intended, the converted unit must be able to meet the applicable equipment standard set forth in the regulations. CFC-12 recover-only equipment may be permanently converted for use with single, specific blend refrigerants under certain conditions. The EPA intends to issue regulations placing certain restrictions on these retrofits in the future. Those restrictions may require that the manufacturer's service representative rather than the automotive service technician perform the retrofit, that a unit may only be retrofitted if retrofit procedures have been certified by an independent testing laboratory such as Underwriters Laboratories, and that an appropriate label is affixed to the unit. In addition, the retrofitted unit has to meet the technical specifications of the EPA standard.

RECYCLING EQUIPMENT

The EPA regulations currently prohibit technicians from recycling blend substitute refrigerants, and the Agency is not aware of any equipment currently on the market designed to recycle any of these blends. After recovering the blend refrigerant from the MVAC system, it must, therefore, be sent off-site for reclamation.

The EPA is working with independent testing laboratories and with equipment manufacturers to determine whether recycling equipment can be developed to service these blends, without jeopardizing the health or safety of the technician and the integrity of the MVAC system. If it is possible to develop such equipment, the EPA will work with equipment and refrigerant manufacturers and with independent testing laboratories to develop an appropriate standard for the equipment.

CONVERTING CFC-12 RECOVER/RECYCLE EQUIPMENT FOR USE WITH BLEND SUBSTITUTES

At the time of publication, the EPA also currently prohibits the conversion of existing CFC-12 or HFC-134a recycling equipment for either temporary or permanent use with a blend refrigerant. In the future, the EPA may issue regulations allowing these conversions but placing certain restrictions on who performs the conversions, what models may be converted, etc.

TECHNICIAN TRAINING AND CERTIFICATION

Technicians who repair or service MVACs with these refrigerants must be trained and certified by an EPA-approved organization. If a technician is already trained and certified to handle CFC-12 or HFC-134a, he will not need to be re certified to handle the blend refrigerants.

RECORDKEEPING REQUIREMENTS

Service facilities that work on vehicles that use blend substitutes must certify to the EPA that they own approved equipment designed to service these refrigerants. Note that this certification is a one-time requirement, so that if a shop purchased a piece of CFC-12 or HFC-134a recycling equipment in the past, and sent the certification to the EPA, the shop does not need to send a second certification to the EPA when it purchases a second piece of equipment, no matter what refrigerant that equipment is designed to handle. If refrigerant is recovered and sent to a reclamation facility, the shop must retain the name and address of that reclaimer.

SALES RESTRICTIONS

Because these blends contain HCFC's, Section 608 regulations prohibit the sale of any size container of any of these blend refrigerants to anyone other than certified technicians. This prohibition began in November, 1994.

Retrofitting Vehicles to Alternative Refrigerants

Although section 609 of the Act does not govern retrofitting, section 612 of the Act, which describes the EPS's Significant New Alternatives Policy (SNAP) program, does require that when retrofitting a CFC-12 vehicle for use with another refrigerant, the technician must first extract the CFC-12, must cover the CFC-12 label with a label that indicates the new refrigerant in the system and other information, and must affix new fittings unique to that refrigerant.

In addition, if a technician is retrofitting a vehicle to a refrigerant that contains R-22, the technician must ensure that only barrier hoses are used in the A/C system. Finally, if the system includes a pressure relief device, the technician must install a high-pressure compressor shutoff switch to prevent the compressor from increasing pressure until the refrigerant is vented.

Refrigeration Cycle

Any automotive air conditioning system employs four basic parts-a mechanical compressor, driven by the vehicle's engine; an expansion valve, which is a restriction the compressor pumps against; and two heat exchangers, the evaporator and the condenser. In addition, there is the refrigerant that flows through this system.

The belt-driven compressor uses engine power to compress and circulate the refrigerant gas throughout the system. The refrigerant passes through the condenser on its way from the compressor outlet to the expansion valve. The condenser is located outside the passenger compartment, usually in front of the vehicle's radiator. The refrigerant passes from the expansion valve to the evaporator, and after passing through the evaporator tubing, it is returned to the compressor through its inlet. The evaporator is located inside the vehicle's passenger compartment.

When the compressor starts running, it pulls refrigerant from the evaporator coil and forces it into the condenser coil, thus lowering the evaporator pressure and increasing the condenser pressure. When proper operating pressures have been established, the expansion valve will open and allow refrigerant to return to the evaporator as fast as the compressor is removing it. Under these conditions, the pressure at each point in the system will reach a constant level, but the condenser pressure will be much higher than the evaporator pressure.

The pressure in the evaporator is low enough for the boiling point of the refrigerant to be well below the temperature of the vehicle's interior. Therefore, the liquid will boil, remove heat from the interior, and pass from the evaporator as a gas. The heating effect produced as the refrigerant passes through the compressor keeps the gas from liquefying and causes it to be discharged from the compressor at very high temperatures. This hot gas passes into the condenser. The pressure on this side of the system is high enough so that the boiling point of the refrigerant is well beyond the outside temperature. The gas will cool until it reaches its boiling point, and then condense to a liquid as heat is absorbed by the outside air. The liquid refrigerant is then forced back through the expansion valve by the condenser pressure.

Refrigerant

A liquid with a low boiling point must be used to make practical use of the heat transfer that occurs when a liquid boils. Refrigerant-12 (R-12) is the refrigerant that was universally used in automotive air conditioning systems. At normal temperatures, it is a colorless, odorless gas that is slightly heavier than air. Its boiling point at atmospheric pressure is -21.7°F (minus 6°C). If liquid R-12 is spilled into the open air, it would be seen for a brief period as a rapidly boiling, clear liquid.

R-12 was nearly an ideal refrigerant. It operated at low pressure and condenses easily at the temperature ranges found in automotive air conditioning systems. It is also non-corrosive, non-toxic (except when exposed to an open flame), and nonflammable. However, due to its low boiling point and the fact that it is stored under pressure, certain safety measures must be observed when working around the air conditioning system. Unfortunately it was discovered the carbo-floro-carbons (CFC's) which were chemicals in the same group as dichlorodifluoromenthane, which you know as R-12 or Freon were depleting the ozone layer of the atmosphere.

On December 31, 1995, CFC-12 production essentially ended in the U.S. However to avoid release into the atmosphere it is still legal to use the existing stockpiles of CFC-12.

The replacement for CFC-12 has been a non-CFC refrigerant R-134a. This has been used since the 1994 model year. Some of the older R-12 systems are being changed over to R-134a but this can be a costly and complicated process on some vehicles.

There is a third category for refrigerants that substitute CFC-12, these also contain ozone depleting HCFC's such as R-22, R142b, and R-124.

There are strict governmental regulations enforced by the clean air act of 1990 section 609. These include specific regulations for the use and handling of each of the three types of refrigerants.

Theory of Air Conditioning

In order to understand how air conditioning works, it is necessary to understand several basic laws about the flow of heat. While it may seem puzzling to talk about heat in the same breath as air conditioning, heat is your only concern. An air conditioner does not cool the air, but rather, removes the heat from a confined space.

The law of entropy states that all things must eventually come to the same temperature; there will always be a flow of heat between adjacent objects that are at different temperatures. When two objects at different temperatures are placed next to each other, heat will flow from the warmer of the two objects to the cooler one. The rate at which heat is transferred depends on how large the difference is between their temperatures. If the temperature difference is great, the transfer of heat will be great, and if the temperature difference lessens, the transfer of heat will be reduced until both objects reach the same temperature. At that point, heat transfer stops.

Because of entropy, the interior of an automobile tends to remain at approximately the same temperature as the outside air. To cool an automobile interior, you have to reverse the natural flow of heat, no matter how thoroughly insulated the compartment might be. The heat which the body metal and glass absorb from the outside must constantly be removed.

The refrigeration cycle of the air conditioning system removes the heat from a vehicle's interior by making use of another law of heat flow, the theory of latent heat. This theory says that during a change of state, a material can absorb or reject heat without changing its temperature. A material is changing its state when it is freezing, thawing, boiling or condensing. Changes of state differ from ordinary heating and cooling in that they occur without the temperature of the substance changing, although they cause a visible change in the form of the substance. While many materials can exist in solid, liquid, or gaseous form, the best example is plain water.

Water is a common material that can exist in all three states. Below 32°F (0°C), it exists as ice. Above 212°F (100°C), at sea level air pressure, it exists as steam, which is a gas. Between these two temperatures, it exists in its liquid form.

Since a change in state occurs at a constant temperature, it follows that a material can exist as both a liquid and a gas at the same temperature without any exchange of heat between the two states. As an example, when water boils, it absorbs heat without changing the temperature of the resulting gas (steam).

The change from a solid to a liquid and vice versa is always practically the same for a given substance-32°F (0°C) for water-but the temperature at which a liquid will boil or condense depends upon the pressure. For example, water will boil at 212°F (100°C), but only at sea level. The boiling point drops slightly at higher altitudes, where the atmospheric pressure is lower. We also know that raising the pressure 15 lbs. above normal air pressure in an automobile cooling system will keep the water from boiling until the temperature reaches about 260°F (127°C)

One additional aspect of the behavior of a liquid at its boiling point must be clarified to understand how a refrigeration cycle works. Since liquid and gas can exist at the same temperature, either the evaporation of liquid or the condensation of gas can occur at the same temperature and pressure conditions. It's just a matter of whether the material is being heated or cooled.

As an example, when a pan of water is placed on a hot stove, the heat travels from the hot burner to the relatively cool pan and water. When the water reaches it's boiling point, its temperature will stop rising, and all the additional heat forced into it by the hot burner will be used to turn the liquid material into a gas (steam). The gas thus contains slightly more heat than the liquid material.

If the top of the pan were now to be held a couple of inches above the boiling water, two things would happen. First, droplets of liquid would form on the lower surface of the lid. Second, the top would get hot very quickly. The top becomes hot because the heat originally used to turn the water into steam is being recovered. As the vapor encounters the cooler surface of the metal, heat is removed from it and transferred to the metal. This heat is the same heat that was originally required to change the water into a vapor, and so it again becomes a liquid.

Since water will boil only at 212°F (100°C) and above, it follows that the steam must have been 212°F (100°C) when it reached the top and must have remained that hot until it became a liquid. The cooling effect of the top (which started out at room temperature) caused the steam to condense, but both the boiling and the condensation took place at the same temperature.

To sum up, refrigeration is the removal of heat from a confined space and is based on three assumptions:

1. Heat will only flow from a warm substance to a colder substance.
2. A refrigerant can exist as both a liquid and a gas at the same temperature if it is at its "boiling point." A refrigerant at its boiling point will boil and absorb heat from its surroundings if the surroundings are warmer than the refrigerant. A refrigerant at its boiling point will condense and become liquid, losing heat to its surroundings, if they are cooler than the refrigerant.
3. The boiling point of the refrigerant depends upon the pressure of the refrigerant, rising as the pressure rises and falling as the pressure falls. The operation of the refrigeration cycle illustrates how these three laws are put to use.