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When using Fyrquel you have a very limited selection of seals that you can use. With the aggressive acids produced by this product you can pretty much use only Viton or Ethylene Propylene seals. I have seen some people using Buna N seals that are not compatible and they have had nothing but issues. If you need anymore info I can email to you
This is real simple, read the manual. Fyrquel EHC is a triaryl phosphate ester which is one of the better types of fire resistant fluids. It is compatible with a range of elastomers as given by Surpresta, Forsythe, Chemtura, EPRI and others. Typically EPR, EPDM, viton, fluorocarbons, PETE, PE, PEEK, Kalrez and even nylon are okay. NOT okay are the various types of nitriles which are the cheap elastomers common on mineral oil systems. It is not because they are acidic but because they are good plasticizers with some materials.
They are widely used to make PVC softer. Interestingly EPR should not be used with mineral oils as it swells them. Check your fluid supplier material.

It would be fluid in very very poor shape to form “powerful acids”. Typically they are weak acids. In any case it is not acidic components that soften seals but phosphate esters are good solvents. You have to use the right seals and paints. Many elastomers are compatible with the triaryl phosphate esters used as EHC such as Viton, EP, EPCDM, butyl, nylon, etc. But do not use Buna-N or butyl rubber as are often used with mineral oil. For your info EP and EPDM should not be used with mineral oil so and again it is not acids but a material effect.

To avoid problems, make sure that you are using the current recommendations from the equipment OEM and from the fluid manufacturers. With the right maintenance, right fluid make-up, correct reservoir design and proper operation the fluid should be trouble free and last decades. Use an acid number of 0.1 mgKOH/g as a maximum, and keep the water content <500 ppm, and the PC < 18/15/12. Training is key.

All the best,

Ken Brown, PEng, MASc, STLE, CLS

Utility Service Associates

Cell 416 458-4189

The problem is not acids! What materials are compatible should be known and given in the fluid suppliers websites and product information. If seals supposed to be FPM are softening or swelling, check that are in fact FPM. Some of the more chemically 'compatible' fluorocarbons are more susceptible to cold setting or flat spotting. Verify the root cause of the failures and test the seals to make sure that they are FPM. There are inexpensive bounce type tester that sometimes work or you can test for the fluorine content.


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