Synthetic Fire-Resistant Fluids
Synthetic fire-resistant fluids: Three types
of synthetic fire-resistant fluids are manufactured:
phosphate esters, chlorinated (halogenated) hydrocarbons,
and synthetic base (a mixture of these two). These fluids do
not contain water or volatile materials, and they provide
satisfactory operation at high temperatures without loss of
essential elements (in contrast to water-based fluids). The
fluids are also suitable for high-pressure applications.
Synthetic fluids have a low viscosity index, anywhere from
80 to - 400, so their use should be restricted to relatively
constant operating temperatures. When required to operate at
low temperatures, these fluids may require auxiliary
heating. Synthetic fluids also have high specific gravities
so pump inlet conditions must be carefully selected to
prevent cavitation. Phosphate esters have flash points above
204C (400F) and auto-ignition temperatures above 483C
(900F), making these fluids less likely to ignite and
sustain burning. Halogenated hydrocarbon fluids are inert,
odorless, nonflammable, noncorrosive, and have low toxicity.
Seal compatibility is very important when using synthetic
fluids. Most commonly used seals such as Nitrile (Buna) and
Neoprene are not compatible with these fluids.