A propane multiple burner test with a fast temperature increase
should be used.
For piping up to 152 mm in diameter, the fire source should
consist of two rows of 5 burners as shown in Figure 1. A constant heat flux averaging
113.6 kW/m2 (± 10%) should be maintained 12.5 ±
1 cm above the centreline of the burner array. This flux corresponds
to a pre-mix flame of propane with a fuel flow of 5 kg/h for a total
heat release rate of 65 kW. The gas consumption should be measured
with an accuracy of least ± 3% in order to maintain a constant
heat flux. Propane with a minimum purity of 95% should be used.
Figure 1 Fire Endurance Test Burner Assembly
For piping greater than 152 mm in diameter, one additional
row of burners should be included for each 51 mm increase on pipe
diameter. A constant heat flux averaging 113.6 kW/m2 (±
10%) should still be maintained at the 12.5 ± 1 cm height above
the centreline of the burner array. The fuel flow should be increased
as required to maintain the designated heat flux.
The burners should be type “Sievert No.2942”
or equivalent which produces an air mixed flame. The inner diameter
of the burner heads should be 29 mm (see Figure 1). The burner heads should be mounted in the same plane
supplied with gas from a manifold. If necessary, each burner should
be equipped with a valve in order to adjust the flame height.
The height of the burner stand should also be adjustable.
It should be mounted centrally below the test pipe with the rows of
burners parallel to pipe's axis. The distance between the burner heads
and the pipe should be maintained at 12.5 ± 1 cm during the
test. The free length of the pipe between its supports should be .8
± 0.05 m.