Definition and classification of flammable and combustible liquids are
addressed in Section 1.7 of NFPA 30. A flammable liquid is defined as a
liquid whose flash point does not exceed 100�F, when tested by closed-cup
test methods, while a combustible liquid is one whose flash point is 100�F
or higher, also when tested by closed-cup methods. These broad groups are
further classified as follows: 
Class IA - Flash Point less than 73�F; Boiling Point less than 100�F 
Class IB - Flash Point less than 73�F; Boiling Point equal to or greater
than 100�F 
Class IC - Flash Point equal to or greater than 73�F, but less than 100�F 
Class II - Flash Point equal to or greater than 100�F, but less than 140�F 
Class IIIA - Flash Point equal to or greater than 140�F, but less than 200�F

Class IIIB - Flash Point equal to or greater than 200�F 
 

Notice that boiling point is only used to distinguish between ClassIA and
Class IB. Class IA liquids are extremely volatile, but there are few liquids
that are so classed. Note also that, theoretically, there is no upper limit
to Class IIIB.

These definitions and classifications were agreed to years ago by NFPA, the
U. S. Department of Transportation (DOT), and the U. S. Occupational Safety
and Health Administration (OSHA) in an attempt to remove inconsistencies in
the definitions used at the time. Since then, DOT has changed its definition
of "flammable liquid" by raising the upper limit to 141�F (60.5�C). This was
done because the United States is a partner to a world-wide set of hazardous
materials regulations sponsored by the United Nations and must use the UN
definitions, at least for international transportation. Note, however, that
DOT regulations include a so-called "domestic exemption" that allows a
shipper to redesignate as a combustible liquid any liquid whose flash point
is in the NFPA Class II range and which does not meet any other hazardous
material definition.

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Rob
Sent: Thursday, April 12, 2012 2:24 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Friday flammables

The other day on the list we were talking about the contents of an air
conditioning system, a propane/isobutane mix was mentioned as was the
un-comfort level of having flammables in that system.

I guess it's all relative.

We are sitting on 15.9 gallons of gasoline with a flash point of -50 degrees
f There is 2.5 gallons of propane that is a gas at -44 degrees f right
behind us (well behind me, I have a westy) We have brake fluid in front of
us, it's a flammable with a high flash point (248 degrees f) but it's still
a flammable.

Springtime most places, not AC weather up here yet but I've read it is some
places, which I guess is why we are talking about AC systems & the like.

Rob

becida@comcast.net
Western Washington State, USA