# Presentation: 381749

## Handbook Chapters 8 and 15

- Oil Burner Test for Cargo Liners

- Contributors:
- George Danker – Chairman
- Ethel Dawson – Accufleet
- Jim Davis – Accufleet
- Ingo Weichert – Airbus Hamburg
- Heinz-Peter Busch – Airbus Bremen
- Bernd Menken – Airbus Bremen
- Jean-Francois Petit – Airbus Toulouse
- Scott Campbell – C&D Aerospace, Huntington Beach
- Anne Mansuet – CEAT, Toulouse

## Areas for Consideration:

- Section 1: Better definition of burnthrough

- Section 2: Expanded backside thermocouple locations for thick samples

- Section 3: Improve and standardize burn apparatus

- Section 4: Guidance on the mounting and attachment of test specimens

- Section 5: Guidance on test methodology

- Section 6: Next steps

## Section 1: Better definition of burnthrough

**1.1 Flame penetration**.  Handbook currently defines burnthrough as “Flame penetration of the
- test specimen”.  This is an inadequate definition which permits the development of voids.
- Flame penetration tends to be directional and geometry alone should not allow for certification.

**Recommendation**: Expand definition of burnthrough to prohibit the development of any void
- through which a flame may pass.

- Suggested language: *Burnthrough is defined as flame penetration of the test specimen *_*or*_* the*
*development of a visible breach, opening, gap, fissure, or any void through which a flame*
_*may*_* penetrate.  The development of any such void during the test period shall be cause for*
*failure.*

- FAATC: Concur.  Although the suggested language may not be perfect,
- it is at least more descriptive than the present definition.

## Section 1: Better definition of burnthrough

**1.2 Panel Shifts / Distortion**

**Recommendation**: (All specimens) Panel shifting, twisting or pulling out of the frame
- creating voids through which flames may pass should be considered a failure.

**Recommendation**: (Cargo liner repair products) Cargo liner patches will occasionally remain
- in place as a result of being supported only by the upward “pressure” exerted by the test flame.
- Such patches will fall off immediately with the removal of the test flame.  This phenomenon
- is thought _not_ to be in the spirit of the fire safety and should not be considered a passed test.

- FAATC: Concur.  Panels _must_ be mounted using the specified stud
- and hole arrangement, so any panel that distorts badly enough to pull
- or twist away from this mounting should be classified a failure.

- FAATC: As stated in 8.10.4, “For the patch adhesion test, the patch
- must be intact after the 5-minute flame exposure”.

## Section 1: Better definition of burnthrough

**1.3 Backside autoignition / flashover.  **Autoignition or Flashover is a troubling issue and
- a very common occurrence:

- cold side autoignition of outgases is common,
- decomposition byproducts combine with stoichiometric volume of air,
- resulting mixture is autoignited by hot surface of underlying panel,
- occurs independently of direct flame contact, independently of burnthrough

- Flashover is currently permitted in Handbook Chapter 8 Supplement 8.10.1. The only
- stipulation being by implication the specimen which “flashes over” is _not_ relieved from
- The 400o F maximum backside temperature requirement of Section 8.10.2

- Suggested clarification _if_ flashover remains permitted:

*A “flashover” is permitted only if no breach is present and only if the backside thermocouple*
*temperature does not exceed 400**o**F*

## Section 1: Better definition of burnthrough

**1.3 Backside autoignition / flashover (con’t)**

- Suggested clarification if flashover is _not_ allowed:

- Suggested: Any flashover on the cold side of the test panel should be of a small to moderate
- size and must self-extinguish within a certain period of time.  A 15-second limit is proposed.

- Flashover is important because:

- Cargo liner tests are not performed very often – thus an approved material may be
- used for years without re-testing,
- The “flashover” definition may not cover all phenomena that might occur,
- The intent of the cargo liner is to contain a fire – not start another fire.

- Note on “Wrap around”:

- Occasionally, the test flame may “wrap around” the test frame and directly ignite
- backside outgases.  This is not considered a failure and baffling (such as sheet metal
- “skirts”) may be used to block the test flame from direct influence on the backside of
- specimens.

## Section 1: Better definition of burnthrough

**1.3 Backside autoignition / flashover (con’t)**

- FAATC: Allow brief (15 second) flashover on back, provided 400oF
- criteria is _not_ exceeded.  Also recommend use of baffle to prevent
- flashover in situations where this presents a problem.

## Section 2: Expanded backside thermocouple locations for thick samples

- Handbook requires that the backside temperature (NTE 400oF) be taken 4 inches from the
- backside of the sample.  This does not adequately consider materials or structures thicker
- than a few millimeters.

**Recommendation**: Position thermocouple 4 inches from the *frontside* of the specimen
- This now creates problems for thick specimens...

- One possible approach:

- _Specimen thickness_

- _Backside thermocouple location_

- Up to 3 inches

- 4 inches from the frontside of specimen

- Greater than 3 inches

- 1 inch from the backside of specimen

- FAATC: ??.  Current 400oF/4-inch requirement based on input from
- airframe manufacturers.  Are there specimens thicker than 3 inches??

## Section 2: Expanded backside thermocouple locations for thick samples

- For cargo liner design features, a technical note reportedly exists describing that design
- features should be tested as flat sheets of material in order to respect the specified flame-
- to-specimen and specimen-to-thermocouple distances.

- FAATC: As stated in 8.8.8.2, “Test procedures for cargo liner design
- features are described in FAA Technical Note DOT/FAA/CT-TN88/33
- dated September 1988”.

## Slide 10

## Testing of Cargo Liner Design Features

- _Design Feature_

- _Testing Method_

- Lighting Fixtures, Pressure Relief Valves

- Material that comprises the fire barrier must
- be tested as a flat sheet, 16- by 24-inch, in
- either the ceiling or sidewall position.

## Testing of Cargo Liner Design Features

- _Design Feature_

- _Testing Method_

- Seams, Joints w/Fastening System

- If seam/joint is found in ceiling liner, it must
- be tested in ceiling position of test liner, long-
- itudinally centered over the burner cone.

- If seam/joint is found in sidewall liner, it must
- be tested in sidewall position of test liner, in a
- longitudinal position 2 inches from top of fixture.

## Testing of Cargo Liner Design Features

- _Design Feature_

- _Testing Method_

- Corner Seam w/Fastening System

- The liner test frame must be altered
- to accept the corner system

## Section 3: Standardize burn apparatus

- Implement as many of Tim Marker’s oil burner changes as make sense.  However, the
- ultimate arbiter of a proper flame continues to be meeting or exceeding the thermocouple
- rake temperatures and heat flux density described in Calibration Section 8.7.

- Temperature across thermocouple rake:        _>_1600oF (_>_871oC)

- Heat flux:                                                        _>_7.5 BTU/ft2second (_>_8.6 w/cm2)

- Burn apparatus improvements include the use of:

- Standardized inlet airhose
- Outboard airflow damper
- Adjustable (rotating/extensible) nozzle

- Permissible adjustments include:

- Minor nozzle variations
- Fuel pressure adjustments to achieve proper fuel flow rate
- Rotation of the nozzle
- Extension or retraction of the nozzle relative to the burner cone
- Optional tabs, static disc, or stabilizers

## Section 3: Standardize burn apparatus

- FAATC: Will consider _RE_-placing tolerances on temperature and
- heat flux (i.e., 1600oF _+_ 100, 7.5 Btu/ft2 second _+_ 0.5), but this
- very group’s input led to its removal, initially.

- Implementation of standardized apparatus configuration and improve-
- ments likely not in the scope at this point.

## Section 4: More specific instruction on mounting/attachment of specimens

- Proposed: Positioning and attachment of test specimens

- Considerable latitude is allowed on specimen attachment.
- Materials must be tested in a “most severe” orientation.  Most vulnerable areas
- of test specimen should be exposed to the center of the test flame.

- Considerable latitude is permitted in method of attaching 16 x 24 test panel to the burn
- frame, provided:

- The attachment of tested feature itself must mimic its attachment in the aircraft.
- Design features, in particular, should be tested in an orientation consistent with
- their installed geometry.
- The burn frame itself should not add reinforcement to any construction that does
- not exist as installed in the aircraft.  Concur.

- FAATC: As per 8.8.8.2, design features tested in most severe
- orientation (longitudinal, centered over flame).  Add more description
- to ensure design feature is tested as installed.

- FAATC: As per 8.8.8.2, fire barriers are tested as flat sheets, result-
- ing in uniform exposure to the flame (no “most severe” orientation).

## Section 5: Test Methodology

- Operational recommendations:

- Dimensions for the Specimen Retaining Frame needs to be increased at least 1⁄4”.  It
- can not be the same size as the test specimen.  Why?
- Standardize fuel to Jet A.  Why?
- Instead of moving the burner into position to begin test, move the test sample to the burner.
- Currently acceptable practice.
- Measure air flow at air source and not at burner.  Changes dynamics of air flow
- Use clamping-locking sample holders instead of bolts.  This will allow samples to twist
- and pull away from frame more easily
- Modify sample holder for testing corner joints.  Remove inner corner angle iron between
- horizontal and vertical test joint.  Currently described in Tech Note.

- Pre-test warmup:

- Two minute warm up before test is unnecessarily long and introduces problems.  Carbon
- builds up in cone and can overheat test chamber environment.

- Recommendation:  Reduce 2 minute warm up to 30 seconds.  Non concur, 2 minute warm
- -up necessary to reach steady state conditions.

## Section 6: Next steps

- Need guidance on recommendations of a “regulatory” nature – most notably Flashover

- Need consensus agreement on test methodology recommendations

- Develop language and incorporate into appropriate sections of Chapters 8 and 15