# Presentation: 285767

## Surrogate Testing

- and
- Proposed Certification Procedures for Altered Interior Surfaces

- Tim Marker

- FAA Technical Center

## Slide 2

## This report discusses:

- material systems,

- -investigates the results of heat release and flammability tests conducted using
- surrogate materials produced by three independent manufacturers.

*“**Heat Release and Flammability Testing of Surrogate Panels”*

## Problem: How to administer OSU or VBB certification tests on renovated cabin interior

- surfaces when appropriate test substrates are unavailable.

**Objective**: To determine if surrogate materials *can* be used as accurate HR and BL
- predictors for in-service materials being renovated.

- A substrate used in-place of existing interior panels for the purposes of conducting
- HR or VBB certification tests.

- A substrate which has the same basic construction and build-up as the OEM Panel,
- with a comparable lay-up process during manufacture.

- Honeycomb core thickness, number of pre-preg plies per side, and reinforcement must
- be identical to the in-service panel.

**Surrogate Material**:

## Surrogate Test Panel Basic Construction

- Paint/Decorative Laminate

- Top-Facing 2-ply Fiberglass

- Bottom-Facing 2-ply Fiberglass

- Core: 0.50-inch Nomex Paper/Phenolic Resin

## Panel Description Code

## Heat Release Test Matrix

## Flammability Test Matrix

## Surrogate Testing

- Baseline Panel Numerical Averages

## Surrogate Testing

## Surrogate Testing

## Surrogate Testing

## Baseline Comparison

## Paint Q Comparison

## Paint R Comparison

## Paint S Comparison

## Laminate T Comparison

## Laminate U Comparison

## Surrogate Testing Results

## Surrogate Testing Results

## Conclusions

- Normal fluctuations between different labs will only compound the inaccuracy of test results.

- Unfinished surrogate panels *did* *not* produce nearly-identical HRR traces, but different
- peaks that occurred at different times.

- HRR differences are compounded when various finishes are applied; these cases represent
- typical in-service situations likely to occur during certification testing of renovated interiors.

- All tests were performed:

- At *one* facility,

- With *one* tester,

- Based on a *large* number of replicate tests;

## Conclusions (con’t)

- Based on the above, it would be very difficult to adopt a *standardized* procedure
- in which renovated interiors could be certified using surrogate materials.

**Expectation**: The increase in HR caused by a particular paint or decorative should be
- independent of the identity of the surrogate panel.

**Result**: HR increase *not* independent of surrogate identity

## Proposed Methodology for Certifying Renovations/Alterations

- (65/65 interior)

**Option 1**: Use flat panel spares supplied by manufacturer of A/C

**Option 2**: Use Cut-out specimen from A/C TBM (To Be Modified)

**Option 3**: If the original HR information is available for the component TBM, and the HRR is:

- Less than 35/35: Fabricate and use surrogate specimen with HRR NLT 40/40

- Less than 45/45, but greater than 35/35: Fabricate and use surrogate specimen with HRR NLT 50/50

- Less than 55/55, but greater than 45/45: Fabricate and use surrogate specimen with HRR NLT 60/60

- Greater than 55/55: Fabricate and use surrogate specimen with HRR NLT 63/63

- *note: surrogate specimen must mimic the interior component TBM in every way, including core type,
- resin type, and thickness and number of pre-preg plies, plus any/all finishes such as paint or decorative.

- *note: if original HR information is not available, this approach cannot be utilized.

## Proposed Methodology for Certifying Renovations/Alterations

- (Pre 65/65 interior)

**Option 1**: Use flat panel spares supplied by manufacturer of A/C

**Option 2**: Use Cut-out specimen from A/C TBM (To Be Modified)

**Option 3**: If the original 60sec VBB information is available for the component TBM, and the BL is:

- *note: surrogate specimen must mimic the interior component TBM in every way, including core type,
- resin type, and thickness and number of pre-preg plies, plus any/all finishes such as paint or decorative.

- *note: if original 60sec VBB information is not available, then a surrogate specimen with BL NLT 5.5 inches may be used

- Less than 1 inch: Fabricate and use surrogate specimen with BL NLT 1.5 inches

- Less than 2 inches, but greater than 1 inch: Fabricate and use surrogate specimen with BL NLT 2.5 inches

- Less than 3 inches, but greater than 2 inches: Fabricate and use surrogate specimen with BL NLT 3.5 inches

- Less than 4 inches, but greater than 3 inches: Fabricate and use surrogate specimen with BL NLT 4.5 inches

- Less than 6 inches, but greater than 4 inches: Fabricate and use surrogate specimen with BL NLT 5.5 inches