NFPA 497, Table 4.4.2. has become my “go-to” source for chemical-physical property data for my flammables (along with the SDS). Although they use Celsius rather than Fahrenheit, and this drives me crazy just because I am “old school”, this table is instrumental for understanding the “Group” your flammable gas/vapors belong to! In the 2021 edition of NFPA 497, Table 4.4.2 was updated to show revised chemical-physical property data and correct CAS numbers. Most of the data has been updated based on the Design Institute for Physical Properties (DIPPR) database. Area electrical classifications throughout the document have been updated to correlate with the NEC electrical classification.