593 

Federal Aviation Administration, DOT 

Pt. 25, App. F 

for placement in the calibration rig during 
burner calibration (figure 5). 

(v) 

Air velocity meter. Use a vane-type air 

velocity meter to calibrate the velocity of 
air entering the burner. An Omega Engineer-
ing Model HH30A is satisfactory. Use a suit-
able adapter to attach the measuring device 
to the inlet side of the burner to prevent air 
from entering the burner other than through 
the measuring device, which would produce 
erroneously low readings. Use a flexible duct, 
measuring 4 inches wide (102 mm) by 20 feet 
long (6.1 meters), to supply fresh air to the 
burner intake to prevent damage to the air 
velocity meter from ingested soot. An op-
tional airbox permanently mounted to the 
burner intake area can effectively house the 
air velocity meter and provide a mounting 
port for the flexible intake duct. 

(4) 

Test specimen mounting frame. Make the 

mounting frame for the test specimens of 

1

⁄

8

- 

inch (3.2 mm) thick steel as shown in figure 
1, except for the center vertical former, 
which should be 

1

⁄

4

-inch (6.4 mm) thick to 

minimize warpage. The specimen mounting 
frame stringers (horizontal) should be bolted 
to the test frame formers (vertical) such that 
the expansion of the stringers will not cause 
the entire structure to warp. Use the mount-
ing frame for mounting the two insulation 
blanket test specimens as shown in figure 2. 

(5) 

Backface calorimeters. Mount two total 

heat flux Gardon type calorimeters behind 
the insulation test specimens on the back 
side (cold) area of the test specimen mount-
ing frame as shown in figure 6. Position the 
calorimeters along the same plane as the 
burner cone centerline, at a distance of 4 
inches (102 mm) from the vertical centerline 
of the test frame. 

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