First published in 1988 and reaffirmed in 1999 and 2005, Standard 29 has been significantly revised in this proposed new edition. The primary change is to clarify the status of Annex A (formerly Appendix A). This previously informative Annex described several possible methods of calorimetry testing, but in this proposed revision, it now specifies a single mandatory method. The descriptions of laboratory testing equipment have also been updated.