CODE OF PRACTICE
FOR
THE USE OF HYDROCARBON REFRIGERANTS
IN
MOTOR VEHICLE AIR CONDITIONING
Published by
The Independent Australian Hydrocarbon
Refrigeration Association
IAHRA
| Revision: | Draft | Final Draft | Final | Revised |
| Date: | Aug '96 | Oct '96 | Nov '96 | Dec '96 |
CODE OF PRACTICE
CONTENTS
This Code of Practice supports best International practices and has been prepared by the hydrocarbon refrigerant industry to ensure the safe use of hydrocarbon (HC) refrigerants in motor vehicle air conditioning systems.
This Code has emerged from consultation between government and industry taking into account environmental responsibilities and Quantitative Risk Assessment studies. The HC Refrigerant Industry is committed to a responsible approach to the environment and maximising the safe use of hydrocarbon refrigerants.
This Code offers a minimum working standard for service technicians. Its aim is to ensure the safety of the vehicles passengers, the mechanic or any other persons who may work on the vehicle. This Code will minimise the loss of HC during the life of motor vehicle air conditioners and to minimise the loss of chemical refrigerants when converting to HCs. This Code covers pre-system servicing, workshop, componentary, repairs, refrigerant disposal and commissioning responsibilities.
Compliance with the Code of Practice does not relieve any corporation, person or member from their obligation to comply with Federal, State or Territory statutory enactments.
It is intended that this Code be adopted by relevant trade associations, education institutes and the industry in general, and be supported by Commonwealth and State Governments. This Code is not exhaustive, but covers a wide range of applications as related to the passenger car air conditioning industry. To this end, the Code must be used with other standards and codes of practice already in existence.
CATEGORIES COVERED BY THIS CODE
1 Passenger cars
2 Off-road passenger vehicles
3 Forward control passenger vehicles
4 Registrable commercial vehicles, mini-buses and omnibuses
5 Any other off-road vehicle including tractors or any farm machinery fitted with an air-conditioning system of a type designed for use in the relevant vehicle.
BRIEF OVERVIEW
1 Accreditation to CFC usage may be a prerequisite under the current relevant ozone depletion Acts in your State or Territory. It is your responsibility to be licensed where applicable.
2 Hydrocarbons are flammable - follow all safety and handling aspects as per Workplace Health and Safety regulations and other applicable Standards.
3 The vehicle Owner, Driver or Operator must be advised and informed about the conversion to and use of HC refrigerants.
Clearly visible system identification is compulsory under this Code:
4 HC refrigerant blends are to be charged as a liquid not a vapour.
5 Storage of Hydrocarbon refrigerants should conform to Australian Standard AS1596 and other relevant State codes.
6 Never overcharge A/C systems, as this will lead to reduced performance and possible over pressurisation. The HC refrigerant charge should never exceed 40% of the CFC or HFC charge by mass.
7 Use accurate weighing methods. Sight glasses are not considered an accurate form of measurement.
8 The installation, commissioning and service of equipment containing HC refrigerants must only be carried out by adequately trained and accredited persons familiar with the particular characteristics of HC refrigerants.
CODE OF PRACTICE FOR THE USE OF
HYDROCARBON REFRIGERANTS IN MOTOR VEHICLE AIR CONDITIONERS
PRE SYSTEM SERVICING
(A) OVERVIEW
This Code of Practice has been prepared to ensure that during system service and repair operations, minimum standards are achieved ensuring the safe handling and operation of hydrocarbon refrigerants. The appropriate Code of Practice for handling CFCs, HCFCs and HFCs should be observed and are the subject of a separate code.
To minimise the environmental damage associated with Chlorofluorocarbons [CFCs], Hydrochlorofluorocarbons [HCFCs] and Hydrofluorocarbons [HFCs] procedures are also included for the recovery and recycling of these chemical refrigerants.
(B) QUALIFIED SERVICE TECHNICIAN
A qualified service technician is defined in this Code of Practice as a person who has worked on motor vehicle air conditioning systems and holds current and relevant accreditation as required by State Authorities and holds a certificate of competency in the use of hydrocarbon refrigerants which is recognised by the Independent Australian Hydrocarbon Refrigeration Association. Various Federal and State legislation also exists in regards to the safe handling of CFC, HCFC, HFC and their blends of refrigerants and it is expected that the service technician will have been accredited through any statutory examinations either practical or theoretical that may be required by the relevant bodies.
Any work conducted by apprentices must be carried out under the direct and personal supervision of a qualified service technician.
(C) SYSTEM EVALUATION
Prior to any work commencing on a motor vehicle air conditioning system, other than decommissioning the following must be conducted:
1. A complete evaluation of the system to identify and note any faults with the system including:
(a) Component leak testing as well as checking for oil stains which may indicate leaks; Flame type leak detectors should not be used.
(b) Condition of pipework and hoses to ensure no major deterioration has occurred;
(c) Condition of condenser and evaporator coils to ensure no visual corrosion or damage has occurred and that air flow has not been restricted;
(d) Review of the specific system installation and operation manual by the service technician to ensure there are no further items specific to the system requiring evaluation or assessment;
2. The owner or operator of the vehicle must then be advised by the service technician of the technician's obligations to conduct work only in accordance with this Code of Practice or statutory rulings and that should the system require repairs it must not be recharged with refrigerant until the necessary repairs have been made.
(D) REGASSING
UNDER NO CIRCUMSTANCES IS A SYSTEM TO BE TOPPED UP WITH ANY REFRIGERANT UNTIL ALL DETECTABLE LEAKS HAVE BEEN RECTIFIED.
WORKSHOP REQUIREMENTS
(E) NECESSARY EQUIPMENT
It is expected that qualified service technicians will have the following equipment available for work on a motor vehicle air conditioning system.
1 Any equipment required under State legislation for refrigerant recovery to reduce the risk of damage to the ozone layer when working with or recovering oils and CFC, HCFC or HFC refrigerants. Such equipment shall confirm to AS4211.1 (1994). The following is applicable to the design and operation of this equipment:
(a) Piping runs on all equipment shall be kept to an absolute minimum where purging is part of the operation of the specific hardware.
(b) Service hose connections to either the low or high pressure sides of the system must include an isolating valve located within 300mm from the service ports. The manifold valve must seal the other end and isolating valves must be provided on all recovery cylinders.
(c) Service hoses may be purged with a small amount of refrigerant prior to commencement of work and it is accepted that at other times some refrigerant will be retained in the hoses between the two respective isolating valves.
(d) Isolating valves shall be closed at all practical times and shall be of a positive off/on design to ensure adequate sealing of the hoses.
2 Vacuum pump in good repair.
3 Manifold and gauge set.
4 Accurate temperature measuring device(s).
5 Soapy water solution or hydrocarbon compatible electronic leak detector.
6 Accurate refrigerant weighing device or charging cylinder.
AIR CONDITIONING SYSTEM COMPONENTRY
(F) COMPRESSOR
1 Compressor mounting brackets and fastening bolts must be assessed for tightness in accordance with the manufacturer's design specifications.
2 Assess the condition of compressor clutch and drive belts to ensure no undue wear has occurred. If in poor condition realign compressor and drive pulley ensuring belt tension is in accordance with the manufacturer's design tolerances.
3 Schrader valve sealing caps are to be checked to ensure correct installation and serviceability.
4 All service valves to have caps fitted, clean and in good condition, complete with "O" rings (copper, aluminium or a synthetic compound).
(G) SUCTION ACCUMULATORS AND REFRIGERANT DRYERS
1 If the system has lost its gas charge then the filter/dryer should be evaluated for replacement after the system has been leak tested and the leaks repaired.
2 If it is required that the system be opened to the atmosphere then the filter/dryer or accumulator must be replaced. This is always to be carried out in accordance with the relevant manufacturers instructions. Caution: work involving refrigerants shall be carried out away from naked flames or other ignition sources.
3 In the event that the system has again to be opened to the atmosphere after the replacement of a newly installed suction accumulator or refrigerant dryer, then unless correctly capped or plugged, these items must be replaced if :
(a) Manufacturer's recommendations require this.
(a) Exposure to the atmosphere has been greater than ten minutes.
(b) If the system has been evacuated of refrigerant for two hours or more and not correctly capped or plugged.
The qualified service technician will also take into account the environment in which this work is taking place to reassess the suggested times according to conditions of excessive dust or high humidity.
Safety is a prime consideration in retrofitting an existing system with any refrigerant.
MAKE SURE YOU ARE WORKING IN A WELL VENTILATED AREA AND OBSERVING ALL SAFETY REGULATIONS.
(H) REFRIGERANT PIPEWORK
After inspection any rubber hoses or metal pipework which have either sustained damage or have deteriorated through ageing shall be replaced in accordance with the relevant codes or in accordance with SAE standards as appropriate.
Should the system include natural rubber hoses then these shall be replaced. Only hoses designed for refrigerants should be used.
(I) REFRIGERANT PIPEWORK CONNECTION POINTS
Only the following methods of connection shall be used for refrigerant hosing used in motor vehicle air conditioning systems:
1 "O" ring seals shall be replaced and lubricated on all mating surfaces (such as gaskets) whenever an "O" ring joint has been opened. Only manufacturer specified "O" rings made from nitrile, neoprene or polyacrylate shall be used.
2 Flared joint connections in accordance with the relevant Refrigeration Tube Fittings Standard.
3 Worm gear hose clamps correctly positioned on the hose connection joint and tightened.
4 Crimped connections using the recommended tools.
Worm gear hose clamps and crimped joints must be replaced with a recommended new fitting if undone.
Prior to charging the system the refrigerant pipework must be cleared of any debris or acid/moisture resulting from the above procedures.
(J) SYSTEM SAFETY PROTECTION
UNDER NO CIRCUMSTANCES IS THE SYSTEM TO BE RECHARGED WITH REFRIGERANT UNLESS THE FOLLOWING CONTROLS HAVE BEEN FITTED:
1 A pressure/temperature relief device where fitted should be vented to the atmosphere and away from any ignition sources, high temperature or high voltage components. Either separate or combined HP/LP (High Pressure/Low Pressure) switches must be installed in all systems with the HP (High Pressure) switch having a lower set point than the pressure/temperature relief device.
2 A device or modification that will prevent the lower explosive limit (LEL) for the refrigerant gas (2% in air by volume for HC) within the passenger compartment of the vehicle from being reached in the event of a refrigerant leak. This requirement will be deemed to be met if :
a) in the case of a device, the device is manufactured for the specific purpose of ensuring that in the case of a refrigerant leakage 20 percent of the LEL within the passenger compartment of the vehicle could not be achieved. The device must come with adequate fitting instructions to enable the device to be correctly fitted to the motor vehicle air conditioning system, or
b) in the case of a modification, that the modification shall have been assessed (or tested) by a laboratory competent to conduct such assessing, as meeting the 20 per cent of the LEL requirement of this Section when used on the design of vehicle being recharged.
RECOMMENDED WORK PRACTICES
(K) TOPPING UP
Under no circumstances is a refrigerant charge in the system to be topped up without checking the integrity of the system FIRST. All leaks must be rectified prior to regassing the system with the any refrigerant.
(l) SYSTEM CLEANING
Under no circumstances are compressed air or refrigerants containing CFC, HCFC or HFCs to be used for flushing the system of contaminants. Low pressure nitrogen should be used for removing air flow restrictions from either evaporator or condenser coils.
(M) REFRIGERANT REPLACEMENT
1. To minimise contamination of a system open for repair or re-charging all open lines shall be plugged or capped immediately.
2 Under no circumstances are refrigerants to be mixed or reclaimed with other refrigerants.
3 CFC, HCFC or HFC refrigerants are to be recovered from a system with a refrigerant recovery unit which meets the requirements of AS4211.1 (1994) and reclaimed.
4 Refrigerants can be kept by the qualified service technician for recycling provided they are not mixed or blended with other refrigerants.
5 The HC refrigerant charge should never exceed a maximum of 40% of the CFC, HFC or HCFC charge by weight. Refer to VACCA recommendations.
RELATIVE CHARGE REQUIRED FOR HYDROCARBON REFRIGERANTS
(Comparison based at 15 deg C)
| System | Mass | Mass | Mass |
| Volume | R12 | HC | R134a |
| 50ml | 67g | 27g | 62g |
| 100ml | 135g | 54g | 124g |
| 200ml | 269g | 108g | 249g |
| 500ml | 673g | 269g | 622g |
| 1 Litre | 1.35kg | 538g | 1.24kg |
(N) LUBRICANTS
1 Hydrocarbon refrigerants are compatible with mineral, ester and Polyalkylene glycol (PAG) oils. Mineral and Ester oils are less toxic and safer to use than PAG oils. We recommend the use of mineral oils which are less toxic and less hygroscopic.
2 When handling PAG oils protective gloves, eye protection and appropriate breathing mask must be worn to avoid vapours and skin/eye contact.
3 The quantity of oil in a system must always be checked in accordance with the manufacturer's recommendations when oil has been removed either during servicing or in the event of a burst hose or leak.
(O) VACUUM AND RE-CHARGING PROCEDURES
1 Gauges shall be calibrated regularly in accordance with the manufacturer's instructions.
2 It is a condition under state and territory legislation that all CFC, HCFC & HFC blended refrigerants be recovered. There are no requirements for recovery of HC refrigerants. HC refrigerants should not be recycled.
Note: If recovery of HC refrigerants is required, a dedicated recovery unit that is suitable to handle flammable refrigerants should be used.
3 Refrigerant reclaim cylinders shall not be overfilled.The cylinder should be check weighed or the level verified to avoid the possibility of cylinder overcharging.
4 The compressor oil level should be evaluated (prior to performance testing) and where possible topped up to the correct level or removed and replaced.
5 The system is to be evacuated to at least minus 90kPa (27"Hg) gauge or approximately 10kPa absolute with the vacuum pump continuing to operate for a period of at least 30 minutes before the system is isolated.
6 One minute after isolating from the vacuum pump the system pressure shall be checked and then further rechecked 15 minutes later.
7 A rise of greater than 2 kPa (0.5" Hg) indicates a leak is present in the system and must be rectified prior to recharging the system.
8 A sufficient refrigerant charge is to be added to the system to facilitate leak testing prior to final system charging.
9 HC refrigerant blends are always to be charged to the system as a liquid to ensure gas blend integrity.
10 The system shall be leak tested with a suitable electronic HC leak detector or soapy water solution prior to performance testing being carried out.
11 The air conditioning system can be serviced in accordance with this Code of Practice and the manufacturer's recommendations when no leak has been detected in the system.
(P) REFRIGERANT STORAGE
1 Refrigerants are to be stored and handled in a cool, dry and ventilated location away from possible ignition sources .
2 All Hydrocarbon refrigerants are to be stored in accordance with AS1596.
3 Cylinders are to be stored in a vertical upright position with refrigerants in cylinders designed and designated to one refrigerant only.
4 Cylinders and valve assemblies shall be regularly checked for signs of damage and returned to the supplier if defective.
5 Valves shall be closed and the valve outlet cover fitted when cylinders are not in use.
6 Under no circumstances are refrigerants to be stored in fuel containers.
PRE CUSTOMER DELIVERY
(Q) SYSTEM NON USE
Where it is required that a vehicle be scrapped or dis-assembled the refrigerant is to be recovered from the system in accordance with clause (M) Refrigerant Replacement except HC refrigerants which may be vented to the atmosphere provided safety requirements have been met.
(R) SYSTEM IDENTIFICATION
Identification in the form of system labelling is to be provided in a prominent location under the bonnet or in the engine compartment of the particular vehicle. The labelling shall be manufactured to withstand engine temperatures and conditions in a material such as polyester or aluminium. The label or tag must include the following detail:
1 Vehicle Identification Number (V.I.N.) or Registration Number
2 Refrigerant type
3 Service technician or organisation
4 Date of service
5 Date of replacement filter/ dryer or accumulator.
6 "Flammable Gas" red diamond to be included on the label or tag .
7 Warning of "non tampering" as system is under pressure.
(S) PRE DELIVERY ADVICE
The owner/operator is to be advised that the system has been either repaired in accordance with this Code or that the system needs to be de-commissioned for non conformance to the Code.
Advice the owner or operator that it is Good Practice to run the system for a minimum of 5 minutes each week no matter what the ambient temperature and that the system should be inspected annually for signs of leakage.
SPECIFICATIONS AND COMPATIBILITY
(T) HC REFRIGERANT QUALITY SPECIFICATION
Component Unit Specification
Tolerances
Saturated Hydrocarbons % >99.5
Ethane % < 2.0
Propane % -
Iso-Butane % -
N-Butane % -
Pentanes % < 0.5
N-Hexane mg/kg < 100
Aromatics mg/kg < 10
Unsaturated Hydrocarbons % < 0.05
(Olefines)
Water mg/kg < 10
Sulphur Compounds mg/m3 < 340
Boiling Point Pressure @ 15 deg C kPa 480 - 570
Temperature Glide kelvin < 12
Lubricant additive % < 2
(U) REFRIGERANT TECHNICAL/PHYSICAL/ENVIRONMENTAL COMPARISONS
Component Compatibility
HC Refrigerants typically have an excellent compatibility with components used in the motor vehicle air conditioning system. A comparison of a system designed for either R12 or R134a would verify a high degree of compatibility: Seals, "O" Rings, Filter-Driers, Hoses, Mineral oils, Polyol ester oils and Polyalkylene glycol oils are compatible with HC refrigerants. There is no need to replace these items on compatibility grounds.
Refrigerant R12 HC R134a
Condensing Pressure : kPa
@ 20 deg C 569 547 572
@ 40 deg C 963 922 1016
@ 60 deg C 1534 1461 1682
@ 80 deg C 2331 2202 2633
Allowable Design Pressures: (R12 system - 1638 kPa @63 deg C)
(Calculated using REF PROP 5.0)
Critical temperature : deg C 112.0 115.4 101.1
Critical pressure : kPa 4180 4000 4067
Energy consumption relative to R12=1.0 1.0 0.86 1.0
Environmental :
Ozone Depleting Potential 1.0 Zero Zero
Global Warming Potential : (100 year) 8500 < 8 1300
Molecular Size : medium large small
Molecular Weight : g/mol 120.9 52.0 102.0
Atmospheric Life : (years) 130 < 1 16
Propensity to leak : Medium Low High
Boiling Point Temperature : deg C -29.8 -32.5 -26.1
Toxicity when burnt : High Extremely High
Low
Explosive Range @ : N/A 2-10% in 7% in air
air @ 1 bar @ 2 bar
Flammable @ atmospheric conditions :
Refrigerant plus oil mixture Yes Yes Yes
Refrigerant only No Yes No
Heat of Combustion MJ/L 0 25 10
Recommended fitting of Yes Yes Yes
new Leakage Limiting Device :
(V) DISPUTE RESOLUTION
In the event that a dispute arises over compliance with this Code the dispute will be referred to the Independent Australian Hydrocarbon Refrigeration Association.