IIR member news: Cemafroid, IRSTEA and AFCE

A new study on the containment of refrigerants has been launched with the aim of identifying and promoting best practices in this regard.
A new study on the containment of refrigerants has been launched with the aim of identifying and promoting best practices in this regard.

Cemafroid and IRSTEA, at the request of AFCE (Alliance Froid Climatisation Environnement), conducted a study from September 2014 to May 2015 on the containment of refrigerating plants. The final report has been translated into English for a larger distribution, although the study was mainly conducted in France.

According to the study, small leaks of refrigeration systems (around 5g/yr, the standard minimum detection level of electronic leak detectors) are extremely common but have very little impact on total emission leakage figures. In fact, it is the small number of large leaks that account for over 90% of the annual leakage mass.

The highest frequency of occurrence (57% of 5g/yr class leaks) represent only a very low relative contribution of 1.12% to the total leakage mass (refrigerant potentially lost). The F-gas regulations and industry standards insist that electronic leak detectors should be able to detect a minimum leakage of 5g/yr. Based on the figures revealed in this study, it raises the question of whether a 5g/yr detection threshold is relevant for leakage testing. Conversely, one can see that 91.6% of the leakage mass is due to classes over 500g/yr.

Moreover, the report suggests that repairing small leaks may actually be more detrimental to the environment. A calculation was made on a case of a 5g/yr leak on a 100 litre liquid tank of a 70kW R404A refrigeration plant with an evaporating temperature of -30°C and condensing temperature of 35°C. It showed that repairing a single 5g/yr leak may be much more harmful to the environment than leaving it as is for 15 years.

The report points out the importance of shut-off valves in order to avoid draining the entire plant to perform the repair. When there is no shut-off valve it advised against the frequent draining of the plant to repair low-rate leakages, instead waiting until the next preventive maintenance operation to perform the repair. Leak detectors equipped with numerous detection thresholds could be a significant step forward in this area, it argues.

During the study, laboratory testing was also used to determine how leak detection methods influenced the performance of measuring instruments. Results showed that the minimum flow rate detected varied according to how the operator used it. For instance, a leak detector calibrated to 5g/yr can detect leaks with a flow rate under 5g/yr, but fails to detect a 5g/yr leak if it is positioned too far away from the source.

The report emphasizes the importance of leak detector verification certificates specifying the instruments’ ideal distance of use for efficient detection of leaks of 5g/yr and over.