What is the AGE Test and when should it be performed? - Part 1

The AGE is an abbreviation for a chemical whose full name is allyl glycidyl ether. (The abbreviation is pronounced as the individual letters A-G-E, rather than like the word "age".) AGE is a chemical that is added to some perchloroethylene-based insulating liquids. The purpose of the AGE additive is to act as an acid scavenger when these liquids were used as permanent retrofill fluids for Askarel (PCB) transformers. As perchloroethylene fluid ages in service, it breaks down and forms hydrochloric acid. The AGE additive acts to neutralize this acid, so that the acid does not react with the metals in the transformer.

Note that the AGE additive applies to perchloroethylene-based retrofill fluids only. Manufacturers of original equipment perchloroethylene insulating liquids addressed the prospect of fluid breakdown and acid formation differently. (For example, Wecosol by Westinghouse is a frequently encountered original equipment perchloroethylene insulating liquid, and it contained a different, proprietary acid scavenger. Wecosol-filled units were made by Westinghouse in the 1980’s and into the early 1990’s.) Therefore, the AGE test is appropriate for samples from former Askarel-filled transformers that were retrofilled with perchloroethylene fluid. This type of retrofill was most commonly performed with the System 50 process (originally owned by ENSR, and later by others), using perchloroethylene fluid named System 50 Fluid, Perclene, or TransClene.

Perchloroethylene was used to flush out and remove the Askarel from the solid insulation of the transformer so that it could be reclassified as non-PCB. Many times the perchloroethylene fluid was not intended to be the final, permanent fluid. In such cases, the perchloroethylene fluid was intended to be a temporary fluid, and the original intention in this case was to replace this perchloroethylene fluid within perhaps 3-12 months with a final fluid, such as silicone.

In some cases, this final retrofill was never completed, so such units may continue to be in service, still containing the "temporary" perchloroethylene fluid. Because such perchloroethylene fluid was not intended to be permanent, it did not contain any acid scavenger. In these cases, the perchloroethylene fluid has most likely broken down and created hydrochloric acid, which has attacked the metals in the transformer, making the transformer unreliable. Such a transformer should therefore be replaced.

If it is unknown whether a given perchloroethylene-filled transformer falls under this particular scenario, the AGE test is appropriate. If the AGE test shows that there is no AGE in the fluid, then regardless of whether or not the perchloroethylene fluid was intended to be permanent, acids have most likely formed and made the transformer unreliable, making it a candidate for replacement.

In Part 2, we will discuss the actual test, how the results are interpreted, and typical recommendations.