Methodologies for PCB Analysis of Transformer Oil (Polychlorinated Biphenyls)
Before their manufacture was banned in 1979, PCBs were used widely in electrical equipment, including transformers and fluorescent light ballasts. Many transformers still contain traces of PCB-contaminated oil even after the oil has been changed several times.
Because of Federal and State regulations, PCB content is frequently required when servicing or disposing of electrical equipment containing insulating fluids.
There are commonly 2 referenced methods used for determining the PCB content in transformer fluids.
EPA SW-846-8082a
ASTM D4059
8082a is a broad scope methodology for testing solids, tissues, and aqueous matrices. The different types of materials are extracted by different methods depending on their type. Solids are different than water and are different than oil. The PCB content can be determined by Congener method, which is by determining each individual PCB compound present, or by Arolclor method, which uses groups of PCB compounds specific to each Arolcor type. Arolclors are groups of PCB compounds with an average chlorination content. Aroloclors are 1016, 1221,1232,1248,1254,1260. Transformer fluids can be analyzed and reported with this method, usually by the Arolclor method.
ASTM D4059 is a transformer fluid specific testing method developed for the electrical insulating fluid industry. It targets a specific extraction methodology specific for electrical insulating fluids. It uses the Aroclor method for determination and targets Aroclors 1260, 1254, and 1242 which comprise most of the contamination in electrical insulating fluids but can determine the other Aroclors as well.
The Quality Control requirements are more extensive in the 8082a EPA method but can also be applied to D4059 testing and usually is by more prudent laboratories.
ASTM D4059 is more applicable for routine screening of electric insulating fluids as part of your maintenance and service of electrical equipment.
