This specification covers the composition and physical properties of lightweight, flexible open-cell polyimide foam insulation intended for use as thermal and sound-absorbing insulation for a certain temperature range in commercial and industrial environments. The insulations are classified into the following types: Types I, II, III, IV, V, and VI. Polyimide foam shall be manufactured from the appropriate monomers, and necessary compounding ingredients. Different test methods shall be performed in order to determine the following properties of the insulation: density, apparent thermal conductivity, upper temperature limit, high temperature stability, compressive strength, compression deflection, compression set, steam aging, corrosiveness, chemical resistance, surface burning characteristics, radiant panel surface flammability, vertical burn, heat release rate, specific optical smoke density, hydrogen halides in smoke, toxic gas generation, and sound absorption coefficients. This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.