R-40 (Methyl Chloride or Chloro-methane) has been found in counterfeit R-134a used in many countries,  as a refrigerant for mobile air conditioners, stationary air conditioning, and transport refrigeration systems.

Research is being conducted by ASHRAE to identify the reaction mechanisms for R-40 and aluminium inside systems, as well as other reaction products. It is also necessary to determine the concentration of R-40 that is safe as a contaminant. AHRI Standard 700-2012, Specification for Fluorocarbon Refrigerants, would allow up to 0.5% of other volatile impurities. There have been no known issues arising from refrigerant that meets AHRI standard 700.

R-22, R410A, R404A are among other contaminated counterfeit refrigerants, very often with counterfeit labels and packaging. Contaminated refrigerants can cause a variety of issues that may range from increasing energy use and decreasing cooling performance, to significantly reducing the operating life of equipment, and even dramatic and injurious equipment failures, as in the case of R-40 contamination. Several container systems have exploded at service facilities, some resulting in fatalities. Some of these systems were found to contain R-40 and/or other unacceptable substances. For your personal safety and to avoid serious injury or death, special care must be taken when accessing the service ports to sample or work on systems that are not functioning properly or have been serviced by others. In addition, some counterfeit refrigerant products contain varying amounts of ozone-depleting substances, which may be illegal in certain parts of the world under the terms of the Montreal Protocol.

So, what can you do to ensure you are not buying contaminated counterfeit refrigerants for your HVAC Systems?

  • It is good practice to use reliable sources selling at market price, preferably from a supplier you know, that can provide traceability.
  • Verify the refrigerant in the cylinders before using them, use a portable refrigerant analyser versions from 2012 onwards or a halide torch test.
  • Proper verification of refrigerant identity and impurity profile in the refrigeration systems prior to repairing and/or servicing the system is a good industrial practice and is imperative to safety. Testing refrigerant in systems prior to removing the charge can also prevent possible contamination of recovery equipment and recovery cylinders.
  • Properly label all suspected contaminated refrigeration systems to ensure that systems containing contaminated refrigerants are quarantined until they can be dealt with properly.

Portable Infrared Analyser

The flow chart below outlines a process for determining if new R-134a supply containers might contain significant amounts of other refrigerant contaminants. This flow chart may not be suitable for use with refrigerant recovered from a system. The new refrigerant container is first analysed in the field with an R-40-capable portable infrared analyser. If the results show 100% R-134a with no other contaminants present, the refrigerant should be suitable for use in systems. If the portable analyser shows a test result other than 100% R-134a, the refrigerant should be quarantined and not used unless further testing shows that the contaminants are below the maximum level recommended by AHRI Standard 700.

Halide Torch Testing
If further field testing to confirm the specific presence of chlorinated impurities is desirable, the optional halide torch testing method may be performed. If the flame in the torch does not turn a greenish colour when the refrigerant sample is introduced, the level of chlorinated compounds is less than several hundred parts per million and the refrigerant is likely suitable for use in systems. A green flame indicates the presence of chlorinated impurities, but these impurities may be acceptable if they have low toxicity and low reactivity in systems, or unacceptable if they are highly reactive or toxic like R-40. Care must be exercised when performing the halide torch test to ensure that the gas flow is optimal for a flame colour reading.

Gas Chromatography or GC/Mass Spectrometer Testing
When laboratory testing is deemed necessary to determine the specific identity of the impurities in the refrigerant container, the optional Gas Chromatography (GC) or GC/Mass Spectrometer (MS) testing may be performed. This test gives detailed information on the composition of the refrigerant and impurities present. If the refrigerant meets the purity requirements of AHRI 700, the refrigerant should be suitable for use in systems.

It is important to be familiar with the operation and instruction manual for all equipment used when testing refrigerants. This is particularly important when using this equipment to detect R-40 contamination.

Maximum Acceptable Levels of R-40
AHRI Standard 700-2012 states that refrigerant impurities may be present at 0.5%, or 5000 ppm or less, in any pure refrigerant or refrigerant blend. Therefore, the maximum level of R-40 that could be found in virgin refrigerant, while very unlikely, could be up to 5000 ppm. AHRI recently conducted a survey of several chemical manufacturers and found that typical R-40 levels in virgin refrigerant from reputable sources were less than 100 ppm. There have been no known issues arising from presence of R-40 impurity in virgin refrigerant, i.e., refrigerant that meets or exceeds the requirements of AHRI standard 700. Any “at risk” HVACR system should be immediately powered down and isolated to minimise the risk of explosion from exposure of the contaminated refrigerant to air or water and to eliminate any potential ignition source.

Source – AHRI White Paper of R-134a Contaminated with R-40 and Other Refrigerants