Page 539 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

Applied Process Design 505

Liquid Mist Explosions

When a flammable liquid is sprayed as fine droplets
into the air, a flammable mixture can result, which may
burn or explode. The mist or spray may be formed by
condensation of saturated vapors or by mechanical means
[ 40). As the particle sizes of the liquid become greater
than 0.01 mm diameter, the lower flammability limit of
the material becomes lower; while above 0.01 mm, the
LEL is about the same as the vapor. Mechanical engine
crankcase explosions of oil mist in air are hazardous, and
current practice is t.o apply explosion relief valves to the
crankcase.
Compressed air system explosions in engines,
pipelines, separators, etc., are characteristic of this same
type of mist explosion.

Relief Sizing: Explosions of Gases and Vapors

The National Fire Protection Association has extensive
codes that relate to fire and explosion prevention and
protection for all major industries and/or occupations,
for example [10, 26, 27, 33, 55). NFPA Code No. 69 [55]

N REACTIVE: SYSTE:H SCRE:E:NING TOOL , ASST
!:!�:mm!'T:r.!����

-J.4 -l. 2

�-- . . . . . . . . . . . . . . . . . :·:·;·:·�:·:·:·:·;·:·:·:·:·:· .
. _. .•••....................
� ...... ·.·•···········•·······························
• • • • • • • • • • • • • • • • • • • • • • • • • • •

Figure 7-61. Reactive system screening tool {RSST) for evaluating runaway reaction potential. By permission, Fauske and Associates, Inc.