Rick M,
Fire resistant doesn't necessarily mean fire proof. Most fire resistant fluids has a Factory Mutual (FM) approval. It really looks at the propagation and sustaining of the flame. An SFP rating or Spray Flammability Parameter is given. The old standard used to be 0, 1 and 2 (not sure if this has changed). Group 0 was non flammable, Group 1 - usually unable to stabilise a flame and group 2 - less flammable than mineral oils but may stabilise a spray flame under certain conditions. There are a number of fire resistant fluid classification HFAE - oil in water emulsion, HFB - water in oil emulsion, HFC - water glycol, HFDR- phosphate esters and HFDU - polyol esters. Obviously the ones with water is less flammable but also requires maintenance. The problem with glycol is that is toxic to the environment and also requires a degree of maintenance. Phosphate esters are also environmental hazards, is toxic and requires compatibility with seals, paints etc. In our part of the world, it is classified as a class 9 dangerous goods so there are disposal issues. The last one being the polyol ester is used where minimum fuss with material compatibility was required and the previous oil say a mineral oil. The use of fire resistant fluids should be carefully considered once a risk assessment has been done also considering what other mechanical fire prevention systems are in place. Most major oil suppliers will have a range of these products. I hope this helps.
