427 

Federal Aviation Administration, DOT 

Pt. 25, App. F 

to the radiant panel surface at this point 
must be 7.

1

⁄

2

inches 

±

1

⁄

8

(191 mm 

±

3). Prior to 

igniting the radiant panel, ensure that the 
calorimeter face is clean and that there is 
water running through the calorimeter. 

(2) Ignite the panel. Adjust the fuel/air 

mixture to achieve 1.5 BTUs/ft

2

-second 

±

5% 

(1.7 Watts/cm

2

±

5%) at the ‘‘zero’’ position. If 

using an electric panel, set the power con-
troller to achieve the proper heat flux. Allow 
the unit to reach steady state (this may take 

up to 1 hour). The pilot burner must be off 
and in the down position during this time. 

(3) After steady-state conditions have been 

reached, move the calorimeter 2 inches (51 
mm) from the ‘‘zero’’ position (first hole) to 
position 1 and record the heat flux. Move the 
calorimeter to position 2 and record the heat 
flux. Allow enough time at each position for 
the calorimeter to stabilize. Table 1 depicts 
typical calibration values at the three posi-
tions. 

T

ABLE

1—C

ALIBRATION

T

ABLE

 

Position BTU’s/ft

2

sec Watts/cm

2

 

‘‘Zero’’ Position ......................................................................................................

1.5 

1.7 

Position 1 ...............................................................................................................

1.51–1.50–1.49 1.71–1.70–1.69 

Position 2 ...............................................................................................................

1.43–1.44 1.62–1.63 

(4) Open the bottom door, remove the calo-

rimeter and holder fixture. Use caution as 
the fixture is very hot. 

(f) 

Test Procedure. 

(1) Ignite the pilot burn-

er. Ensure that it is at least 2 inches (51 mm) 
above the top of the platform. The burner 
must not contact the specimen until the test 
begins. 

(2) Place the test specimen in the sliding 

platform holder. Ensure that the test sample 
surface is level with the top of the platform. 
At ‘‘zero’’ point, the specimen surface must 
be 7

1

⁄

2

inches 

±

1

⁄

8

inch (191 mm 

±

3) below the 

radiant panel. 

(3) Place the retaining/securing frame over 

the test specimen. It may be necessary (due 
to compression) to adjust the sample (up or 
down) in order to maintain the distance from 
the sample to the radiant panel (7

1

⁄

2

inches 

±

1

⁄

8

inch (191 mm

±

3) at ‘‘zero’’ position). With 

film/fiberglass assemblies, it is critical to 

make a slit in the film cover to purge any air 
inside. This allows the operator to maintain 
the proper test specimen position (level with 
the top of the platform) and to allow ventila-
tion of gases during testing. A longitudinal 
slit, approximately 2 inches (51mm) in 
length, must be centered 3 inches 

±

1

⁄

2

inch 

(76mm

±

13mm) from the left flange of the se-

curing frame. A utility knife is acceptable 
for slitting the film cover. 

(4) Immediately push the sliding platform 

into the chamber and close the bottom door. 

(5) Bring the pilot burner flame into con-

tact with the center of the specimen at the 
‘‘zero’’ point and simultaneously start the 
timer. The pilot burner must be at a 27

° 

angle with the sample and be approximately 

1

⁄

2

inch (12 mm) above the sample. 

See 

figure 

7. A stop, as shown in figure 8, allows the op-
erator to position the burner correctly each 
time. 

VerDate Sep<11>2014 

12:50 Apr 30, 2019

Jkt 247046

PO 00000

Frm 00437

Fmt 8010

Sfmt 8002

Y:\SGML\247046.XXX

247046

spaschal on DSK3GDR082PROD with CFR