"Butch Davis" wrote in message
k.net...
There is a difference between a gas and a vapor? I thought there were
liguids, fluids, and gases. Fluids covering both bases? But with a
refrigeration background my thoughts are probably too simplistic.
Butch

Vapor is emitted from a liquid or solid (in it's normal state) at a specific
temperature and pressure. Flammable or combustible liquids start to emit
vapor at a specific flash point (temperature). It is the vapor that burns,
not the liquid. Combustible liquids such as hydraulic oil are not generally
considered dangerous unless reaching their flash point or atomizing
(increasing their overall surface area exposed to air in a relatively small
area) such as in the case of a pinhole leak in a hydraulic line under
pressure.

Gas has very low density and viscosity (compared to liquids) and may be
compounds or elements. They can be liquefied by pressure. Flammable
gasses (e.g. hydrogen, an element) have explosive limits (lower and upper)
depending on their percent by volume in air. There are know the their LEL
and UEL.

Dust can be explosive (if from a non inert product) when suspended in air
and falling within the LEL and UEL concentration.