: For assessing the explosion-hazard of a gaseous mixture in equilibrium with a flammable liquid, such as the atmosphere above the liquid surface in an enclosed vessel, it is of little use to show the concentration for the flammability of the vapor in air, but temperatures that are defined as lower and upper flashing temperature, are essential. There have only been a few instances so far where a series of these measured or estimated temperatures were reported for a variety of flammable liquids.
    The author has been aware of the importance of the above two flashing temperatures for some time past and examined by measuring them for many substances. Some of the results are given in this report, in the form of temperature vs. vapor pressure diagram which shows the relationship between flashing temperatures and flammability limits, for estimating the explosion-hazard characteristics of industrial chemicals or liquids at a glance.
    In the report the general idea and the importance of the flashing temperatures are first described, subsequently followed by the method of measurement and main points of drawing the diagrams. Secondly, the diagrams for important substances from industrial safety point of view are presented for each substance.

Keywords ;Gas explosion, Flammability limit, Flashing temperature, Vapor pressure.