AC 25-17A

Advisory circular · Transport Airplane Cabin Interiors Crashworthiness Handbook

Approved
May 18, 2009
Last reviewed
June 27, 2016
Cancels
AC25-17
Family
AC 25-17 · 2 versions
Revision
A
14 CFR parts
25
Cited by
1 AD

Guidance, not mandatory unless a rule or AD requires it. DRS record last changed October 23, 2026.

Show pages 722–733
Page 734Open in PDF

(c) Calibration of Equipment.—

(1) Heat Release Rate. [A burner as shown in Figure 4 must be placed over the end of the lower pilot flame tubing using a gas tight connection. The flow of gas to the pilot flame must be at least 99 percent methane and must be accurately metered. Prior to usage, the wet test meter is properly leveled and filled with distilled water to the tip of the internal pointer while no gas is flowing. Ambient temperature and pressure of the water are based on the internal wet test meter temperature. A baseline flow rate of approximately 1 liter/min is set and increased to higher preset flows of 4, 6, 8, 6, and 4 liters/min. The rate is determined by using a stopwatch to time a complete revolution of the wet test meter for both the baseline and higher flow, with the flow returned to baseline before changing to the next higher flow. The thermopile baseline voltage is measured. The gas flow to the burner must be increased to the higher preset flow and allowed to burn for 2.0 minutes, and the thermopile voltage must be measured. The sequence is repeated until all five values have been determined. The average of the five values must be used as the calibration factor. The procedure must be repeated if the percent relative standard deviation is greater than 5 percent. Calculations are shown in paragraph (f).]

(2) Flux Uniformity. Uniformity of flux over the specimen must be checked periodically and after each heating element change to determine if it is within acceptable limits of plus or minus 5 percent.

(d) Sample Preparation.

[(1) The standard size for vertically mounted specimens is 150 X 150 mm with thickness up to 45 mm).]

(2) Conditioning. Specimens must be conditioned as described in Part 1 of this Appendix.

(3) Mounting. Only one surface of a specimen will be exposed during a test. A single layer of

0.025mm aluminum foil is wrapped tightly on all exposed sides.

(e) Procedure.

(1) The power supply to the radiant panel is set to produce a radiant flux of 3.5 W/cm2. The flux is measured at the point which the center of the specimen surface will occupy when positioned for test. The radiant flux is measured after the air flow through the equipment is adjusted to the desired rate. The sample should be tested in its end use thickness.

(2) The pilot flames are lighted and their position, as described in paragraph (b)(8), is checked.

(3) The air flow to the equipment is set at 0.04 plus or minus 0.001 m3/s at atmospheric pressure.

Proper air flow may be set and monitored by either: (1) An orifice meter designed to produce a pressure drop of at least 200mm of the manometric fluid, or by (2) a rotometer (variable orifice meter) with a scale capable of being read to plus or minus 0.0004 m3/s. The stop on the vertical specimen holder rod is adjusted so that the exposed surface of the specimen is positioned 100mm from the entrance when injected into environmental chamber.

Page 735Open in PDF

(4) The specimen is placed in the hold chamber with the radiation doors closed. The airtight outer door must be secured, and the recording devices must be started. The specimen must be retained in the hold chamber for 60 seconds, plus or minus 10 seconds, before injection. The thermopile "zero" value must be determined during the last 20 seconds of the hold period

(5) When the specimen is to be injected, the radiation doors are opened, the specimen is injected into the environmental chamber, and the radiation doors are closed behind the specimen.

(6) [[Reserved.]]

(7) [Injection of the specimen and closure of the inner door marks time zero. A record of the thermopile output with at least one data point per second must be made during the time the specimen is in the environmental chamber.]

(8) The test duration is five minutes.

(9) A minimum of three specimens must be tested.

(f) Calculations.

(1) The calibration factor is calculated as follows:

F0 = flow of methane at baseline (1pm) F1 = higher preset flow of methane (1pm) V0 = thermopile voltage at baseline (mv) V1 = Thermopile voltage at higher flow (mv) Ta = Ambient temperature (K) P = Ambient pressure (mm Hg) PV = Water vapor pressure (mm Hg) [(2) Heat release rates may be calculated from the reading of the thermopile output voltage at any instant of time as:

HRR = Heat release Rate kw/m2 Vm = measured thermopile voltage (mv) Kh = Calibration Factor (Kw/mv)]

(3) The integral of the heat release rate is the total heat release as a function of time and is calculated by multiplying the rate by the data sampling frequency in minutes and summing the time from zero to two minutes.

( ) ( ) ( )Kh F1 F0V1 V0 210.8 - 22 kc almole 273Ta P P v760 moleCH4STP22.41 WATTmin.01433kcal kw1000w= −− × × × − × × × ( )HRR Vm Kh .02323 m2= ×

Page 736Open in PDF

(g) Criteria. The total positive heat release over the first two minutes of exposure for each of the three or more samples tested must be averaged, and the peak heat release rate for each of the samples must be averaged, and the peak heat release rate for each of the samples tested must be averaged, and the peak heat release rate for each of the samples must be averaged. The average total heat release must not exceed 65 kilowatt-minutes per square meter, and the average peak heat release rate must not exceed 75 kilowatts per square meter.

(h) Report. The test report must include the following for each specimen tested:

(1) Description of the specimen.

(2) Radiant heat flux to the specimen, expressed in W/cm2.

(3) Data giving release rates of heat (in kW/m2) as a function of time, either graphically or tabulated at intervals no greater than 10 seconds. The calibration factor (kn) must be recorded.

(4) If melting, sagging, delaminating, or other behavior that affects the exposed surface area or the mode of burning occurs, these behaviors must be reported, together with the time at which such behaviors were observed.

(5) The peak heat release and the 2-minute integrated heat release rate must be reported.

Page 737OCROpen in PDF

Smoke Monitor • Chimney 025m→

• Baffle

0.31m → 0.368m Radiation Shield Reflector

• 0.33m "Globars"

0.79m Mechanical Devise to Maintain Sample Pilot Position Flame

- 0.41m L semple Holder Air Distributor Plates -

- 0.41m

- 0.20m - Air Inlet [Figure 1. Release Rate Apparatus] 721

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Top 115 150 . Mask 156 (Unless denoted otherwise, all dimensions are in millimeters.)

[Figure 2A. "Globar" Radiant Panel] 722

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TOP T -25- 115 • Reflector, adjust slope, top and bottom, for uniform heat flux on sample.

- Mask

- 1/4" - 20 Machine Screw 75 g (Unless denoted otherwise al dimensions are in millmeters.)

[Figure 2B. "Globar" Radiant Panel] 723

Page 740OCROpen in PDF

SPRING 2 Radlus Flange, 1" Frami "3/8" 156 .020 ANGLE IRON Stainless RETAINER FRAME Steel Wire 165 24 ga Steel

SAMPLE HOLDER Washer 50mm OD 13mm ID Weld her 50mm OD 13mm ID Screw Drill & \Tap for Weld 10-32 Machine Screw 1/2 - 13 nut 1/2" Nut to Washer 2 Radlus, 5 Flange 165

MOUNTING BRACKET (Unless denoted otherwise, all dimensions are in millimeters.)

[Figure 3.] 724

Page 741OCROpen in PDF

- 125mm → 25

- 25 — No. 32 Drill Hole

- 9.5 O.D.

9.5 Tubing Leak-Free Seal on 6.35 Pilot Tubing (Unless denoted otherwise, all dimensions are in millimeters.)

[Figure 4.] 725

Page 742Open in PDF

1181 – 1185. [RESERVED]

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727 1186. APPENDIX F, PART V, DID NOT EXIST PRIOR TO AMENDMENT 25-66.

1187. APPENDIX F, AMENDMENT 25-66, Effective September 26, 1988.

PART V - TEST METHOD TO DETERMINE THE SMOKE EMISSION

CHARACTERISTICS OF CABIN MATERIALS

(a) Summary of Method. The specimens must be constructed, conditioned, and tested in the flaming mode in accordance with American Society of Testing and Materials (ASTM) Standard Test Method ASTM F81483.

(b) Acceptance Criteria. The specific optical smoke density (DS), which is obtained by averaging the reading obtained after 4 minutes with each of the three specimens, shall not exceed 200 1188 – 1192. [RESERVED]

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729 1193. APPENDIX F, PART VI, DID NOT EXIST PRIOR TO AMENDMENT 25-111.

1194. APPENDIX F, AMENDMENT 25-111, Effective September 2, 2003. This amendment revised Part I and added Parts VI and VII.

[PART VI-TEST METHOD TO DETERMINE THE FLAMMABILITY AND FLAME

PROPAGATION CHARACTERISTICS OF THERMAL/ACOUSTIC INSULATION MATERIALS] [Use this test method to evaluate the flammability and flame propagation characteristics of thermal/acoustic insulation when exposed to both a radiant heat source and a flame.

(a) Definitions.

"Flame propagation" means the furthest distance of the propagation of visible flame towards the far end of the test specimen, measured from the midpoint of the ignition source flame. Measure this distance after initially applying the ignition source and before all flame on the test specimen is extinguished. The measurement is not a determination of burn length made after the test.

"Radiant heat source" means an electric or air propane panel.

"Thermal/acoustic insulation" means a material or system of materials used to provide thermal and/or acoustic protection. Examples include fiberglass or other batting material encapsulated by a film covering and foams.

"Zero point" means the point of application of the pilot burner to the test specimen.

(b) Test apparatus.