During the last decade, significant improvements have become available in flammability testing. Rationally- based new methods, derived from fundamental engineering principles are replacing the previously used empirical tests. The major emphasis in this development work has been to provide a basic set of bench-scale methods which can be used to predict full-scale product performance. Reference methods for conducting full-scale tests will continue to be needed to handle products or situations where the bench-scale methods are not applicable. The bulk of the testing needs, however, can now be fulfilled by use of bench-scale tests which are not only simple to run, but are known to predict accurately the full-scale performance.