Fire Heat Intensities

API RP 521

Fire heat intensity	kW/m2	Btu/h-ft2
Open pool fire	50-150	15,850-47,550
Jet fire	100-400	31,700-126,800
Confined pool fire	100-250	31,700-79,250

A pool fire typically results from an ignited liquid spill, whereas a jet fire results from an ignited pressurized leak. The heat flux from jet fires is very high and localized, whereas the heat flux from pool fires is lower and not localized.

 

Scandpower, Guidelines for the Protection of Pressurised Systems Exposed to Fire 

(kW/m2)	Jet fire		Pool fire
	For leak rates m> 2 kg/s	For leak rates m> 0.1 kg/s (Note 1)
Local peak heat load	350	250	150
Global average heat load	100	0	100

This calculation is for an object located close to the leak source. The heat flux will vary during the fire duration, and 250kW/m2 is used as the average incident heat flux.