Contaminated refrigerant is two or many types of refrigerants mixed in the cylinder or refrigeration and airconditioning system knowingly or unknowingly.
Contaminated refrigerant is different from refrigerant blends. Contaminated refrigerant is sub-standard blends, which has negative effects on the system. Refrigerant blends are mixtures of refrigerants that have been formulated to provide a match to certain properties of the refrigerants originally used. These blends have been researched and developed by the manufacturers – examples: R 400 series, R 500 series.
Effect of contaminated Refrigerant to the R & AC System
Damage to R & AC system
Reduce cooling capacity, consume more electrical energy and reduce efficiency system
Significantly reducing the operating life of equipment
Explosion may occur causing personal injury
Some counterfeit refrigerant products contain varying amounts of ozonedepleting substances, which may be illegal in certain parts of the world under the terms of the Montreal Protocol.
Known Composition of Counterfeit R134a Refrigerant
60% R22 (+ R30, R142b – traces)
40% R40 – methyl chloride
Compounds such as R-40, R-22, R-142b, R-152a, and R-12 have been found mixed with R-134a in newly filled refrigerant cylinders marked as containing R-134a. There have also been instances of counterfeited brand name R-134a cylinders sold containing refrigerants other than R-134a. Unfortunately, the problem with counterfeit and contaminated refrigerants goes beyond just R-134a. Other refrigerants including R-22, R-404A, and R-410A, have also been found to be counterfeit and in some instances badly contaminated. Cylinder labels and packaging have been counterfeited in some instances, and therefore, are not reliable indicators of the authenticity of the contents of a cylinder.
Reasons for why R40 mixtures are in market
Price of HFCs has recently increased, meaning more reasons to fake HFC refrigerants
Potential excess HCFCs in the market
Case Study A
18 Oct 2011 – Reefer Containers machinery explosions due to contaminated refrigerant
Maersk Line had experienced three cases in which the compressors of the refrigeration units had exploded for no apparent reason. The explosions occurred on three separate occasions in 2011 in Itajai, Brazil and Cat Lai, Vietnam. Two men died in Vietnam and one in Brazil as a result of the explosions. CMA CGM also reported that explosion occurred in one of their refrigerated containers in Qingdao, China, in October.
The four reefer machines that experienced compressor ruptures received refrigeration system service work at Cat Lai in Vietnam. Maersk Line identified the malfunctioning containers underwent gas system repairs and maintenance at the same repair yard in Vietnam between 30 March 2011 and 25 April 2011.
Preliminary analysis appears to confirm suspicions that the cause of the explosions was contaminated gas in the cooling units. Material recovered from the exploded units had been analysed and evidence pointed to a counterfeit refrigerant being to blame for the explosions.
R40 was definitively identified as a contaminant. R40 called methyl chloride or chloromethane, is a hazardous chemical compound that is extremely flammable. It was a widely used refrigerant, but its use has been discontinued due to its toxicity and flammability. The most important use of methyl chloride today is as a chemical intermediate in the production of silicone polymers. R40 reacts with aluminium and creates Trimethylaluminum which is a pyrophoric substance that will ignite spontaneously in air.
As a result, Maersk Line had grounded 844 refrigerated containers that may contain contaminated coolant fluid, while CMA CGM has grounded 332 and Singapore-based-APL has grounded around 103 as a precautionary measure.
Furthermore, fluorocarbon producers have warned customers to only purchase refrigerants from authorised suppliers. They are also adopting measures to address counterfeit refrigerants. Honeywell started using a new security measures to detect counterfeit refrigerants. The new anti-counterfeit technology allows for the identification of non-authentic products much faster and more easily than was previously possible. DuPont Refrigerants has initiated DuPont Brand Assurance Program. The Brand Assurance Program uses a proprietary DuPont technology which involves 3D holographic label.
The boiling point of R40 is similar to that of R134a, hence it is very difficult to detect R40 when they are mixed in the refrigerant system. The only practical method to ensure that R134a being added during service repairs is free from R-0 and any other chemical containing chlorine, is to use a flame halide detector to test each R134a cylinder for any chlorine contamination. R134a is fluorinated and does not change the blue colour of the flame. A green flame indicates the presence of chlorine, e.g., R- 22 will show a green flame because it contains chlorine.
There is evidence that R40 has been supplied in 30lb. cylinders and marked as R134a.
Case Study B
7th August 2013 – Explosion of compressor of fridge under repair due to contaminated refrigerant
On 7th August 2013, two youngsters working in a refrigerator cum air conditioning work shop at Hyderabad. They were filling the gas (nitrogen) in the pipe of the fridge which was under repair. An explosion occurred at 4:45pm. Both the youngsters sustained blast injuries and succumbed to severe disruptive injury on the spot. The impact of the blast was so severe that the fridge dismembered into smithereens, ceiling fan and window panes were shattered into pieces. They ran out till the gate and collapsed. One of the vehicles parked outside the workshop was knocked down due to explosion and was layered with bluish colour material [melted flex banner]. Surprisingly, the compressor tank was found intact amongst the debris of blast.
Autopsy Findings: At autopsy following injuries were observed:
Victim-1: Blast injury at centre and left side neck extending into upper part of the chest cavity with massive disruption of muscles, nerves, vessels and fracture of C6 and C7 cervical bone. Multiple fragmentations of left forearm fracture of tibia, fibular bone with toned muscles, tissues and vessels.
Victim-2: Abdomen blasted with expelling out its contents with puncturing of intestines with multiple liver lacerations and multiple perforations. Blast injury extending from midline of chest to the right nipple with underlying tissue contused, fracture of 6th rib right in the mid clavicle line.
The samples collected from the scene of blast; analysed at FSL by the flame Halide lamp test [A blue flame indicates the presence of normal gas while the green flame indicates the presence of chlorine] demonstrated the presence of chlorinated compounds. Traces of alumina (AL203) were also found at the site.
Discussion: Meticulous articulation of observations at autopsy and scene of blast was attempted to scientifically deduce the mechanism of explosion in the present case. Causes and mechanism of explosion reported so far were also taken onto account.
Figure 2: Flow chart for determining contaminants in R-134a
Causes of Explosion
The refrigerator explosions take place even after it was proved that R134a is an alternative to CFC’s, safest and environmental friendly. It is now widely known that the contamination of the refrigeration systems is because of the addition of counterfeit refrigerant which uses a mix of chemicals including R40. R40 is a hazardous chemical compound that is extremely flammable. It was widely used in refrigerators in the past which stopped now. R40 reacts with aluminium and creates trimethyl aluminium which will ignite spontaneously in air. The boiling point of R40 is similar to that of R134a; hence it is difficult to detect R40 when they were mixed into the refrigeration systems.
Explosion Mechanism
Usually, the registration units contain polyester oil and the refrigerant HFC-134a, which cease the exploding capability of the refrigerator. But use of hazardous chemical compounds such as R40 along with R134a makes the refrigerator more vulnerable to explosion. R40 works as a refrigerant and at times it reacts with the aluminium in the compressor probably forming Trimethyl Aluminium is a liquid at room temperature. According to Wiley’s Guide to Chemical Incompatibilities, the extreme reactive quality of liquid trimethyl aluminium will make it react violently with hydroxides; carbon dioxide, carbon tetrachloride, halon, halogens, oxides of nitrogen and many other substances. Excessive moisture in refrigeration systems may also cause corrosion. The combination of moisture with hydrofluorocarbon (HFC) refrigerant containing chlorine creates much more serious corrosion, as the chlorine hydrolyses with the water to form hydrochloric acid (HCl) which is aggressive. The acid forming process in turn is aggravated by heat. It is obvious; in the present case; that the gas cylinder used for filling up the compressor was contaminated with methyl chloride and was responsible of chemical reaction with coils or tubes of compressor accessories leading to explosion. The recovered material from the explosion site also showed the presence of chlorinated compounds and traces of alumina (AL203).
Figure 3: Infrared Specific Identifier
Figure 4: Infrared Component Identifier
Figure 5: Never obstruct the air intake
Refrigerant analysis can be done with any of the following methods:
Pressure or Temperature Relationship
Halide Lamp
Infrared Specific Identifier
Infrared Component Analyser
Gas Chromatograph
Mass Spectrometer
While there are no known portable refrigerant analysers produced prior to 2012 with any capability to detect R-40, several models were introduced in 2012 with the capability to detect R-40 quantities as low as 2-3 per cent. These devices also have the capability to detect other contaminants, including CFCs and hydrocarbons. Halide torch testing has the capability to detect chlorinated compounds as low as 300 ppm; however, the method is not capable of detecting other contaminants, such as hydrocarbons. Using a combination of the two methods provides the widest range of contaminant detection available in a field test.
A pressure-temperature (PT) relationship check is not a recommended procedure to determine if a refrigerant cylinder is contaminated, as a contaminated system that contains a refrigerant blend could indicate pressures similar to those of pure R-12 or R-134a.
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 or 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.
Portable Infrared Analyser: The flow chart at right outlines a process for determining if new R-134a supply containers might contain significant amounts of other refrigerant contaminants. The 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 per cent 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 per cent 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.
Figure 6: Use right hoses
Principle of Operation
Non-Dispersive Infra-Red
Single detector with multi-channel filter wheel
Includes 90-240 VAC power supply
Low pressure vapour refrigerant sample or high-pressure liquid sample using the supplied flash chamber.
Accuracy: Better than +/- 2 per cent
Displays refrigerant components and their corresponding percentages.
Operation – Cautions & Warnings
1. Never obstruct the air intake, sample exhaust or cease vent ports of the instrument during use.
2. Always verify that the refrigerant to be tested does not contain or will not emit heavy loads of oil or liquid. Vapour samples only! Introducing liquid refrigerant will cause serious damage to the identifier.
3. Do not utilise any other hose other than those supplied with the instrument. The use of other hose types will introduce errors into the refrigerant analysis.
Suggestions to Prevent Such Explosions
Know Your Supplier: Obtaining refrigerant from a trusted and well
known source that can provide traceability is good practice to prevent contamination of an HVACR system.
Verify Refrigerant in Cylinder Before Using: Proper verification of refrigerant in service cylinders prior to use can ensure authenticity of the refrigerant. Checking refrigerant cylinders in the field with a portable refrigerant analyser or performing a halide torch test can also help prevent contamination.
Verify Refrigerant in System Before Repairing or Servicing: Proper verification of refrigerant identity and impurity profile in the refrigeration systems prior to repairing 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 and Isolate Contaminated Refrigeration Systems: Properly label all suspected contaminated refrigeration systems to ensure that systems containing contaminated refrigerants are quarantined until they can be dealt with properly, as discussed below in the remediation section.
The withdrawn units should be checked for contamination.
Once a contaminated unit has been identified, a procedure for making
them safe needs to be identified. There is no method till now for the removal of Trimethyl Aluminium and yet to be identified.
Existing refrigerant stock needs to be checked for contamination.
A refrigeration certification scheme needs to be put in place for future purchases.
A method to check the withdrawn reefer units for contamination.
A safe method for compressor removal of contaminated units to be identified.
No repairs are attempted, parts cannot be removed.
They may not be plugged in until completion of the thorough technical investigation.
They should be stored in an isolated place.
Do not expose to suspected refrigerant to sunshine! May evolve high vapour pressure.
It is also very important to prevent unauthorised personnel in tampering with the equipment.
