Hi Jim

You bring up a great point.  As an experimental, there are no requirement for materials to be cert'd to FAR 25.853 (flammability).  All of the materials I am putting in Dave Morss' Legacy however, meet flammability.  As you say Jim, it's something that everyone should insist on.

Interestingly, I worked at trying to convince a major bus company of the need for flammabilty resistance for their insulation and they were not interested. They use ordinary bead foam that burns a bit like gasoline.  True, there are few instances of fatalities in busses burning but most other companies are moving toward flame resistance.  As for large commercial aircraft, an AD is pending that will make fire hardening of fuselages even more strict and will require burn-through protection 4years from when it is adopted, and 2 years for the stricter cabin fire standards.