SAE standards
The Society of Automotive Engineers (SAE) has clear standards covering the safe handling
and use of refrigerants.
CFC-12 SAE documents:
● SAE J1989: Service procedures
● SAE J1990: Specifications for recycling equipment
● SAE J1991: Standard of purity
● SAE J2209: CFC-12 Extraction equipment
HFC134a SAE Documents:
● SAE J2211: Service procedures
● SAE J2210: Specifications for recycling equipment
● SAE J2099: Standard of purity
● SAE J1732: HFC134a Extraction equipment
Handling refrigerant
Technicians often recover refrigerants from an A/C system during service. Depending on how these refrigerants are processed after removal, they can be classified as recycled, reclaimed, or extracted.
Before an A/C service machine is connected to an A/C system the refrigerant analyser must be used to sample the refrigerant. If the results indicate an NCG (Non-Condensable Gas) of no less than 98% then the refrigerant can be internally recycled to remove any service contaminants. If the analyser shows an NCG of less than 98% then the refrigerant should be reclaimed or disposed off using the correct procedures.
When handling refrigerant the following precautions must be observed:
- Do not handle refrigerant in an enclosed area or near an open flame.
- Always wear PPE (Personal Protective Equipment).
- Be careful that refrigerant does not get in your eyes or on your skin.
If liquid refrigerant gets in your eyes or on your skin:
- Do not rub the area.
- Wash the area with a lot of cool water.
- Apply clean petroleum jelly to the skin.
- Go immediately to a physician or hospital for professional treatment.
When replacing parts on refrigerant line:
- Discharge refrigerant slowly before replacement.
- Insert a plug immediately in disconnected parts to prevent entry of moisture and dust.
- Do not leave a new condenser or receiver-drier etc., lying around with the plug removed.
- Discharge nitrogen gas from the charging valve before removing the plug from the new compressor.
- Do not use a burner for bending or lengthening tubes.
If the nitrogen gas is not discharged first, compressor oil will spray out with the nitrogen gas
when the plug is removed.
When tightening connecting parts:
- Apply a few drops of compressor oil to O-ring fittings for easy tightening and to prevent leaking of refrigerant gas.
- Tighten the nut using two wrenches to avoid twisting the tube.
Identifying refrigerants
Every vehicle with an air-conditioning system has a sticker located on the bonnet lock panel
indicating the refrigerant used:
Filled with R12 Black sticker.
Filled with R134a Gold and yellow sticker.
Converted to R134a Pale blue sticker.
All refrigerant containers are clearly labelled showing the grade of refrigerant they contain.
TABLE
Recycled refrigerant (remove containments during normal operation)
Recycled refrigerant is cleaned to remove contaminants produced during normal operation of the A/C system. This is in the form of air, water and oil. The air is vented to the outside, the water is absorbed by a desiccant and the oil is separated. Most modern A/C machines include recycle facilities which are automatically built into the recovery process. Recycled refrigerant must meet the same standards as virgin refrigerant as stated in SAE J1991 and J2099. Standards of purity must not affect the performance or warranty of the system. Refrigerants sent off site for processing and from other sources must meet ARI 700 standard or EN12205 to ensure that the refrigerant is not contaminated and is in compliance with the law.
The SAE J2099 standard of purity for recycled HFC134a refrigerant for use in mobile A/C systems, which has been directly removed from automotive A/C systems, shall not exceed the following levels of contaminants:
● Moisture: 50 ppm (parts per million) by weight.
● Refrigerant oil: 500 ppm by weight.
● Non-condensable gases (air): 150 ppm by weight.
Single-pass recovery system
In single-pass systems refrigerant is drawn from the vehicle A/C system and then passes through an oil separator.This removes any oil.The filter/drier assembly removes moisture and particle contamination. After a single cycle, the contaminant-free, recycled refrigerant, is sent to a storage container.
Multi-pass system
In multi-pass systems refrigerant is drawn from the vehicle, passed through an oil separator, which removes any oil, and a filter/drier assembly, which removes moisture and particle contamination, and is then stored in a tank. When recycling is desired, the recycle solenoid valve is opened, allowing a continuous loop-filtering process in which the refrigerant passes througha desiccant (drier) cartridge several times, until the moisture is fully removed. The station has an indicator to alert the service technician or will automatically vent the recovery tank to remove air. An indicator will show when the refrigerant is ready for use.
Reclaimed refrigerant (contaminated with foreign refrigerant)
Reclaimed refrigerant is processed to the same standards and purity as new refrigerant. This process requires expensive equipment not ordinarily found in service departments. An A/C technician may send a refrigerant to be reclaimed if it contains a foreign refrigerant. The recovery of a refrigerant to be reclaimed must not be carried out using the same recovery equipment for R12 or R134a. Each refrigerant must use a separate machine and this includes contaminated and blends.
Extracted refrigerant (recovered but not recycled only stored)
Extracted refrigerant is simply removed and stored in an approved container. This process is used when servicing the refrigeration system and the refrigerant must be removed and stored from the A/C system.
Key dangers in using extracted refrigerants
The main sources of contamination in recovered refrigerants are:
Moisture – possible icing up of the expansion valve and reduced heat transfer of the
evaporator could increase the formation of acid oil sludges.
Non-Condensable Gas (NCG) – chemically inert gases in a refrigerant system can cause the
following:
● reduced cooling efficiency;
● higher than normal head pressures;
● higher discharge temperatures.
3. Organic contaminants – these result from decomposition of various organic materials such as oil, insulation, varnish, gaskets and adhesives.This may cause problems by plugging small orifices resulting in restricted or plugged capillary tubes or sticky expansion valves.
4. Metallic contamination:
● scoring of metallic components within compressors and bearings;
● lodging in the motor insulation of a hermetic or semi-hermetic system causing shorts;
● plugging oil holes in compressor parts thus leading to improper lubrication;
● serving as a catalyst to increase the rate of chemical breakdown in the system.
Note – this is why it is very important to use a refrigerant analyser and an A/C machine
with recycle capabilities.
Storing refrigerant
Note – refrigerant cylinders must be stored according to BS4434 recommendations.
Both R12 and R134a are gases at normal room temperature, and they can be hazardous if stored improperly. New refrigerant stored in its original, properly filled container usually poses no safety hazard. However, recycled refrigerant can be dangerous if it is stored in the wrong type of container or in an overfilled container. To prevent accidents when handling recycled refrigerant, never save disposable refrigerant containers for reuse. Remove all refrigerant and dispose of the containers properly. Only use containers approved for refrigerant. Never fill a container to more than 60% of container capacity. Never store refrigerant containers in direct sun or heat. High temperature causes the gas to expand, which increases the pressure in the container and may cause the container to burst.
To monitor the container pressure, install a calibrated pressure gauge with 6.9 kPa or 1 psi divisions and a thermometer to monitor the temperature within 10 cm of the container. Ensure that the pressure at the measured temperature does not exceed the limit given in Table 5.1
Refrigerant transfer
In the event that a refrigerant is required to be transferred from one storage container to another, the recipient (container to be filled) must be evacuated of air first.The container must be fitted to a vacuum pump and evacuated to at least 635 mm (25 inHg) below atmospheric pressure (vacuum) before transfer.
Refrigerant disposal
If a refrigerant cannot be recycled and contains hydrocarbons or other contaminants which prevent further use then it must be disposed of. This is achieved through following local government requirements. If the procedures are unknown then contact the local council office.
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