20. NOTE
‣ The fire inspector witnesses system
tests. The actual system tests are
performed by the installing contractor’s
representatives. This practice helps
minimize fire service liability should a
system component fail.
70. Fire spread is often expressed in
terms of heat transfer.
71. Fire spread is often expressed in
terms of heat transfer.
72. Fire spread is often expressed in
terms of heat transfer.
73. Thermal radiation intensity can be calculated
via the Stefan-Boltzmann law of physics.
The Stefan-Boltzmann law (physics) states that the
intensity of thermal radiation (T) is a function of the
fourth power of the absolute temperature of the
thermal radiation source (T4), or:
(Fire Temperature in R) 4_
(Ambient Temperature in R) 4
Fahrenheit can be converted to Rankine (R) using the formula:
R = (ºF – 32) + 491.67
74. Heat transfer becomes a problem in communities
because of exposures and fire progression
factors.
75. There are many ways that fires spread
to exposed buildings and objects.