The code change that allowed elimination of heads is a couple decades old.
We were confused about meaning. I’d like to say I can remember who I talked
with or have notes. I don’t. I know the re-emphasis by FM concerning both
heated and unheated combustible liquids being aerosolized by high
1. FM has Approval Standard 693 wherein some non-water based
fire-resistant hydraulic fluids are certified.
2. There are tests for noncombustibility, from ASTM, and they are cited
in NFPA 130 and NFPA 101.
3. Approval using interpretation from the AHJ, which takes into
consideration
See related forum post for additional info:
NFPA 30- 2015:
4.2.2 Combustible Liquid. Any liquid that has a closed-cup flash point at or
above 100°F (37.8°C), as determined by the test procedures and apparatus set
forth in Section 4.4. Combustible liquids are classified according to Section
The old "lesser combustible" or "less combustible" definitions are of no value.
Look at the SDS for the material. If there is a flashpoint, it is categorized
within the IBC and NFPA 30. A liquid with a flashpoint of over 200°F is a
class IIIB combustible. While IIIB liquids pose the least
