1.1 A training program is established which allows Design and Applications Engineers, Installation, Service and Maintenance Engineers to attend college and obtain recognised qualifications.
1.2 In-house training is given during which the Company’s Policy and Standards are introduced, these then being maintained by the Supervision and Management structure.
2.1 The appreciation and application of established technology in both design and construction of refrigeration systems constitutes a good foundation for the prevention of refrigerant leakage. Likewise, the awareness of development in new technology which has been tested and marketed for our industry allows the Company to promote safer alternative methods and materials.
2.2 Design/Applications Engineers shall use quality, well-proven equipment to maintain overall system integrity and give serious consideration to the following to maintain this Policy:-
2.2.1 The use of alternative refrigerants whenever technically and economically feasible. Selection of Refrigerant is to be based on EN378 (Safety & Environmental Requirements) and using the industry standard calculation; TEWI (Total Equivalent Warning Impact).
2.2.2 The type, assembly and positioning of associated equipment fitted to compressors to prevent leaks e.g. Gauge and cut-out connections, oil return, oil drains, oil level sight glass, refrigerant level sight glass, relief valve and connecting pipework.
2.2.3 Prevention of vibration by the inclusion of anti-vibration mountings and vibration eliminators and the use of suitable flexible high-pressure hosing for connection to gauges and pressure switches.
2.2.4 The adequate use of shut off valves to allow isolation of gauges, pressure cut-outs and serviceable components during servicing or replacement.
2.2.5 Pipework shall be designed so that the number of joints is kept to the absolute minimum. Brazing is to be used wherever practicable.
2.2.6 Brazing shall be used to join a flange to pipework and attention must be given to the selection of gaskets, or joining material to withstand the pressures and temperatures involved.
2.2.7 All pipework to be correctly supported against vibration stresses with the inclusion of vibration eliminators and expansion bends.
2.2.8 The use of efficient strainers, filters and dryers to minimise the chance of damage by dirt, metal or moisture. The inclusion of a moisture indicating liquid line sight glass.
2.2.9 The use of valves with facilities for tightening or replacement of the gland packing/diaphragm. The valves to be complete with caps to retain any leakage from the spindle gland, and brazed or flanged connections in preference to flared or screwed types.
2.2.10 The system design shall be such that there is adequate margin between the normal working pressure and the relief valve setting to avoid any unnecessary operation of the pressure relief valve.
2.2.11 The system is fitted with liquid receiver or receivers or components, all of which shall be isolatable and be of sufficient capacity to hold the complete refrigerant charge to facilitate pump down during servicing or repairs.
2.2.12 The fitting of suitable valves and connections to allow refrigerant and oil charging without leakage, and likewise removal.
3) INSTALLATION AND SERVICING
3.1 The installation engineer shall be fully briefed on the system design, application of components, and methods of installation to maintain this policy. He will be instructed to gain a knowledge of items listed under Section 2 above, and in addition, will ensure the following:-
3.1.1 All pipework, fittings and components are thoroughly examined for cleanliness prior to fitting into position.
3.1.2 That no pipework is left unsealed to allow ingress of filings, dirt or moisture all of which cause damage.
3.1.3 If flare connections are used, these are formed with great care and tightened correctly.
3.1.4 Only the correct type of gasket material is used with flanged connections etc.
3.1.5 During brazing, dry nitrogen should be allowed to bleed continuously through the system to eliminate oxidation which can be a common cause of choked driers, dirty oil and compressor failure.
3.1.6 For leak testing the system is pressurised with dry nitrogen and leak tested using soap bubble method.
3.1.7 Deep evacuation shall be used wherever practicable. If triple evacuation of a system is undertaken, Oxygen Free Nitrogen should be used to break the vacuum first two stages.
4) ROUTINE SERVICE AND MAINTENANCE
4.1 The Service and Maintenance Engineers will be instructed to gain a knowledge of items listed under Sections 2 and 3 above, and in addition, will ensure the following:-
4.1.1 Not to use refrigerant gas for the purpose of cleaning debris and dirt from air cooled condenser fins and similar equipment. Air or dry nitrogen is to be used whenever necessary.
4.1.2 To replace, tighten or retighten (i) valve stem glands (ii) blanks over gauge ports,
(iii) service valve caps, all of which shall be thoroughly leak tested after a service.
4.1.3 Check all hoses / pipework for wear / rubbing and reposition / secure to avoid future leaks.
4.1.4 If a system is found short of refrigerant, the leak is to be found prior to topping up and great care must be exercised in examining brazed joints, bellows, and shaft seals etc.
4.1.5 Ensure when leak testing the low side that there is positive pressure.
4.1.6 Ensure when repairing the leak that this part of the system is isolated to minimise the further loss of refrigerant. The refrigerant charge should be pumped down into the system receiver to allow isolation, or when found to have an insufficient pump down capacity, decanted / transferred to suitable bottles.
4.2 When cleaning and flushing a contaminated system the refrigerant should be transferred to suitable empty bottles taking care not to overfill these bottles. NOTE:- Refrigerant gases must not be mixed in the same bottle, and the bottle must be of the distinguishable type for recovered refrigerant to allow return to the manufacturer. The refrigerant manufacturers’ recommendations to be adhered to at all times.
5) RECOVERY, RE-USE, DISPOSAL AND STORAGE OF REFRIGERANTS
5.1 During servicing operations or system alterations /modifications refrigerant should be pumped down into the system receiver and isolated. The refrigerant may be re-used upon completion of works with the addition of refrigerant (if applicable) to obtain the correct working charge.
5.2 If the system receiver is of insufficient size then the refrigerant bottles may be used as temporary receivers, providing the bottle is suitably marked for such operation and is marked as compatible with the system refrigerant. This refrigerant may be re-used providing there is no contamination in the system from whence it came and also providing there is no specific change from one refrigerant type to another.
5.3 Be aware that hazards arise in transferring refrigerant and consideration shall be given to the following:-
5.3.1 The bottle designed maximum working pressure and designed carrying capacity must not be exceeded during any filling operation, however temporary. Observe Refrigerant Manufacturer’s recommendations.
5.3.2 Refrigerant / oil mixtures have a lower density than refrigerant alone and therefore the carrying capacity of refrigerant bottles will be reduced for refrigerant / oil mixtures. Observe Refrigerant Manufacturer’s recommendations.
5.3.3 Contaminated refrigerant may be corrosive and therefore it is imperative that it is transferred to the appropriate distinguishable bottle for recovered refrigerant which will allow return to the manufacturer. The manufacturer will then inspect the bottle to ascertain whether it remains serviceable.
5.3.4 Mixing different refrigerant types must be avoided. The receiving bottle shall have been used previously only for the refrigerant type which is being transferred.
5.4 If the refrigeration system is to be removed, modified or altered such that the refrigerant is to be recovered and cannot be used from whence it came, then the refrigerant is to be transferred to the appropriate distinguishable bottle to allow return to the manufacturer.
5.4.1 All contaminated refrigerant and refrigerant removed from sites belonging to Clients who have not entered into a recycling agreement, the refrigerant will be returned to a manufacturer for full reprocessing or disposal.
5.4.2 Where our customers have entered into a reclaim / recycle agreement and we have established service and maintenance records; hence we have a history of equipment performance and a knowledge of system conditions; i.e. whether there has been any serious contamination or any possibility of mixed refrigerants; the refrigerant removed from site may be recycled by our plant and stored for future reuse by the same Clients.
5.4.3 In reclaiming the refrigerant it will be transferred to certified distinguishable bottles which shall have been only used previously for the refrigerant type being transferred.
5.5 Losses of refrigerant to atmosphere can occur during the handling and storage of refrigerant bottles.
5.5.1 During storage bottles should be in a cool place away from fire risk and sources of direct heat.
5.5.2 Bottles should not be dropped thus avoiding damage to the bottle and its valves.
5.5.3 Bottles not in use should have valves closed, the valve outlet cover nut fitted and the valve protection cover replaced.
5.6 When in use pipework between bottle and system should be leak tested prior to fully opening.
5.6.1 Charging and transfer lines should be as short as possible to avoid losses during disconnection at the end of transfer. Care should be taken to avoid refrigerant liquid being trapped between closed valves.
5.6.2 Refrigerant bottles shall not be connected to a system at a higher pressure or temperature thus avoiding any backflow. N.R.V’s should be used when systems are charged in the liquid phase.
5.6.3 Refrigerant bottles shall not be manifolded together.
5.6.4 Transfer between bottles must be carried out using safe and approved methods.