REFRIGERANTS
Refrigerant gas detection– compliance or management?
Tom Burniston, product manager of fixed instrumentation at Bacharach takes a look at the importance of leak detection.
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efrigerant gas detection has been used in the marketplace for many years. The drivers for this have included safety, regulation, cost, energy efficiency, environmental protection and protection of the workplace and product inventory or produce. Currently the refrigeration market in Europe is seeing an increased awareness of all these factors driven by the F-Gas regulations and the associated impact these changes are having, and will have into the future.
As the refrigeration market shapes itself to adjust to tighter industry regulation, two distinct approaches are becoming apparent when looking at refrigerant gas detection – compliance, and refrigerant management.
Compliance
F-Gas 517/2014 determines that refrigeration systems containing gas with a global warming potential (GWP) of 500 tonnes CO2
(carbon dioxide) equivalent or greater must have a permanent leak detection system installed. Those with more than five tonnes CO2
equivalent must be inspected,
with mandated intervals for inspection halved if a permanent leak detection system is installed.
F-Gas is, however, not the only relevant legislation regarding refrigerant detection. EN 378-3:2008+A1:2012 states that systems with a charge of greater than 25kg refrigerant shall be fitted with a refrigerant detection system in the machinery room, designed to trigger ventilation when concentrations reach 50% of the occupational exposure limit (OEL) or 25% of the lower flammability limit (LFL). In addition, an alarm must be activated if the potential concentration of leaking refrigerant may exceed the practical limit in accordance with EN 378-1:2008+A2:2012, Annex C. These two regulations, in addition with safety codes related to the asphyxiation risk from CO2 spaces (for example, cold rooms using CO2
in enclosed as a refrigerant), are driving an increased need for compliance-focussed 44 August 2017
refrigerant detection in the commercial environment. Most frequently this type of gas detection instrument will be employed in a machinery room housing compressor, chillers and other large refrigeration plant.
The devices used for this type of compliance refrigerant detection are generally fairly simple and very cost effective. Typically, these instruments consist of a fixed position point detector with a localised audio-visual alarm, and some form of external communications capability such as relays, analogue output signals or BUS communications. These are used to drive alerts to then instigate actions to mitigate the leak.
The technology used in these instruments is well suited for this type of gross leak detection, with alarms typically in the region of 500 ppm (parts per million) for HFC refrigerants, usually at 5,000ppm or higher for CO2
. What this technology
delivers, is a solution that ticks the box for compliance with regulation, and for safe operation of systems. Increasingly, more users of refrigerant gas are seeing a need to monitor gas leakage at much lower levels to facilitate other benefits from the systems put in place. This approach is known as ‘refrigerant management’.
Refrigerant management
Technology exists which can monitor the presence of refrigerant at levels as low as one part per million (ppm). This type of high precision sensor is usually found at the heart of aspirated, sampling systems which use a pump to draw a gas from the monitored area back to the gas monitoring system for analysis.
There are two reasons for this; the cost of the sensor elements is prohibitive to deployment in multiple locations on one site, and the size of the sensor does not allow for it to be housed as a small point detector. However, used appropriately to monitor from multiple zones, this type of system can be very cost effective to install.
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