Surrogate Testing and Proposed Certification Procedures for Altered Interior Surfaces Tim Marker FAA Technical Center

-the difficulties associated with the fire test approval of renovated material systems, -investigates the results of heat release and flammability tests conducted using surrogate materials produced by three independent manufacturers. This report discusses: “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

Baseline Comparison

Paint Q Comparison

Paint R Comparison

Paint S Comparison

Laminate T Comparison

Laminate U Comparison

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