The use of hydrocarbon refrigerant has significantly increased over the last 10 years, most notably in the retail sector. This is due to good performance and low environmental impact. Flammable refrigerants like R290 (propane) and R1270 (propylene) are being used in equipment located indoors (with charges up to 1.5 kg) and in outdoor located systems, like chillers (with charges typically of 10 kg per circuit). For engineers working on hydrocarbon systems there is an increased emphasis on the safe working environment.
Cool Concerns Ltd provide practical training, consultancy and technical support for the refrigeration and air conditioning industry. They specialise in providing practical training for engineers working with hydrocarbon refrigerants and work closely with manufacturers to provide consultancy and expert knowledge.
An area where a hydrocarbon refrigerant, such as propane (R290) or isobutane (R600a), is being handled can be potentially flammable, for example if a leak were to occur or when hoses are purged. For this reason the working area must be free from sources of ignition and sparking electrical devices. The ‘safe zone’ is a 3 metre radius around the equipment being serviced and should contain no sources of ignition, ie. naked flames or sparking electrical devices. The area must be monitored with a hydrocarbon sensor, located at low level. The sensor should provide an audible and visual alarm if there is HC in the air, well before there is enough to form a flammable mix (approximately 2% of HC in air by volume). To reduce the potentially flammable zone good ventilation is essential. This means that in many internal areas, forced ventilation is required. With htis requirment in mind, RDA developed the Care-Air fan module, a safety devise that provides forced ventilation in the working area when working with flammable refrigerant. It uses an ATEX approved fan motor, which is safe for use in a flammable atmosphere. The 5 metre power cable enables switching the device on / off, outside of the potentially flammable area.
Standard recovery machines suitable for use with HFC’s are not safe for use with hydrocarbon refrigerant. The use of inbuilt components, eg. high and low pressure switches and relays, inhibit the use of standard recovery units when working with HC refrigerant. The Caresaver Universal is a recovery unit designed specifically for use with hydrocarbon refrigerants (as well as standard HFC refrigerants). The Caresaver is a rugged, portable machine capable of recovering both liquid and vapour / gas. It has an inbuilt self-discharge feature to minimise the mixing of refrigerants. Importantly for use on HC systems, the Caresaver Universal has a low pressure over-ride, enabling it to pull systems down to a deeper vacuum. This feature is essential for engineers to safely un-braze connections on hydrocarbon systems. The Caresaver Universal ensures that as much hydrocarbon has been removed from the system as possible. Nitrogen can then be used to “back-fill” the system to a very slight positive pressure. This ensures that any small amount of HC remaining in the system is mixed with Nitrogen and that air cannot be drawn into the system creating a potentially flammable mix that would be dangerous when un-brazing.
Engineers working with hydrocarbon refrigerants should be trained in accordance with the specification in EN378-4:2008 Annex E. The knowledge outlined in this Annex is covered in the awareness training provided by Cool Concerns Ltd, and includes:
- An introduction to HC refrigerants;
- Performance and operating conditions;
- Flammability and sources of ignition;
- Service procedures;
- Maximum charge sizes.
Short videos are included to illustrate safe working practices such as the recovery procedure outlined above.
Visit Cool Concerns website for further information about the services they provide, including HC training, consultancy and technical support – www.coolconcerns.co.uk/
For more information on the hydrocarbon refrigerant safety devices and recovery equipment we provide, please contact us on +44 (0) 1983 821189 / firstname.lastname@example.org