442 

14 CFR Ch. I (1–1–19 Edition) 

Pt. 25, App. F 

Ensure that the horizontal centerline of 

the burner cone is also offset 1 inch below 
the horizontal centerline of the thermo-
couple tips. Re-check measurements by ro-
tating the burner to each position to ensure 
proper alignment between the cone and the 
calorimeter and thermocouple rake. (Note: 
The test burner mounting system must in-
corporate ‘‘detents’’ that ensure proper cen-
tering of the burner cone with respect to 
both the calorimeter and the thermocouple 
rakes, so that rapid positioning of the burner 
can be achieved during the calibration proce-
dure.) 

(2) Position the air velocity meter in the 

adapter or airbox, making certain that no 
gaps exist where air could leak around the 
air velocity measuring device. Turn on the 
blower/motor while ensuring that the fuel so-
lenoid and igniters are off. Adjust the air in-
take velocity to a level of 2150 ft/min, (10.92 
m/s) then turn off the blower/motor. (Note: 
The Omega HH30 air velocity meter meas-
ures 2.625 inches in diameter. To calculate 
the intake airflow, multiply the cross-sec-
tional area (0.03758 ft

2

) by the air velocity 

(2150 ft/min) to obtain 80.80 ft

3

/min. An air 

velocity meter other than the HH30 unit can 
be used, provided the calculated airflow of 
80.80 ft

3

/min (2.29 m

3

/min) is equivalent.) 

(3) Rotate the burner from the test posi-

tion to the warm-up position. Prior to light-
ing the burner, ensure that the calorimeter 
face is clean of soot deposits, and there is 
water running through the calorimeter. Ex-
amine and clean the burner cone of any evi-
dence of buildup of products of combustion, 
soot, etc. Soot buildup inside the burner 
cone may affect the flame characteristics 
and cause calibration difficulties. Since the 
burner cone may distort with time, dimen-
sions should be checked periodically. 

(4) While the burner is still rotated to the 

warm-up position, turn on the blower/motor, 
igniters and fuel flow, and light the burner. 
Allow it to warm up for a period of 2 min-
utes. Move the burner into the calibration 
position and allow 1 minute for calorimeter 
stabilization, then record the heat flux once 
every second for a period of 30 seconds. Turn 
off burner, rotate out of position, and allow 
to cool. Calculate the average heat flux over 
this 30-second duration. The average heat 
flux should be 16.0 

±

0.8 Btu/ft

2

sec (18.2 

±

0.9 W/ 

cm

2

). 

(5) Position the burner in front of the ther-

mocouple rake. After checking for proper 
alignment, rotate the burner to the warm-up 
position, turn on the blower/motor, igniters 
and fuel flow, and light the burner. Allow it 
to warm up for a period of 2 minutes. Move 
the burner into the calibration position and 
allow 1 minute for thermocouple stabiliza-
tion, then record the temperature of each of 
the 7 thermocouples once every second for a 
period of 30 seconds. Turn off burner, rotate 
out of position, and allow to cool. Calculate 

the average temperature of each thermo-
couple over this 30-second period and record. 
The average temperature of each of the 7 
thermocouples should be 1900 

°

F 

±

100 

°

F (1038 

±

56 

°

C). 

(6) If either the heat flux or the tempera-

tures are not within the specified range, ad-
just the burner intake air velocity and re-
peat the procedures of paragraphs (4) and (5) 
above to obtain the proper values. Ensure 
that the inlet air velocity is within the 
range of 2150 ft/min 

±

50 ft/min (10.92 

±

0.25 m/ 

s). 

(7) Calibrate prior to each test until con-

sistency has been demonstrated. After con-
sistency has been confirmed, several tests 
may be conducted with calibration con-
ducted before and after a series of tests. 

(f) 

Test procedure. 

(1) Secure the two insula-

tion blanket test specimens to the test 
frame. The insulation blankets should be at-
tached to the test rig center vertical former 
using four spring clamps positioned as shown 
in figure 7 (according to the criteria of para-
graph paragraph (c)(3)(iv) of this part of this 
appendix). 

(2) Ensure that the vertical plane of the 

burner cone is at a distance of 4 

±

0.125 inch 

(102 

±

3 mm) from the outer surface of the 

horizontal stringers of the test specimen 
frame, and that the burner and test frame 
are both situated at a 30

° 

angle with respect 

to vertical. 

(3) When ready to begin the test, direct the 

burner away from the test position to the 
warm-up position so that the flame will not 
impinge on the specimens prematurely. Turn 
on and light the burner and allow it to sta-
bilize for 2 minutes. 

(4) To begin the test, rotate the burner into 

the test position and simultaneously start 
the timing device. 

(5) Expose the test specimens to the burner 

flame for 4 minutes and then turn off the 
burner. Immediately rotate the burner out of 
the test position. 

(6) Determine (where applicable) the 

burnthrough time, or the point at which the 
heat flux exceeds 2.0 Btu/ft

2

-sec (2.27 W/cm

2

). 

(g) 

Report. 

(1) Identify and describe the 

specimen being tested. 

(2) Report the number of insulation blan-

ket specimens tested. 

(3) Report the burnthrough time (if any), 

and the maximum heat flux on the back face 
of the insulation blanket test specimen, and 
the time at which the maximum occurred. 

(h) 

Requirements. 

(1) Each of the two insula-

tion blanket test specimens must not allow 
fire or flame penetration in less than 4 min-
utes. 

(2) Each of the two insulation blanket test 

specimens must not allow more than 2.0 Btu/ 

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