The large chamber test for toxic fumes analysis of permissible explosives

This paper describes the procedure for analysis of toxic fumes from the detonation of high explosives using the Large Chamber at the US Bureau of Mines (USBM), Pittsburgh Research center (PRC). This test is specified in 30 Code of Federal Regulations (CFR) Part 15.20 (g) as a requirement for the Mine Safety and Health Administration`s (MSHA) approval of an explosive as permissible for use in underground coal mines. The Large Chamber replaced the Bichel gauge and Crawshaw-Jones (C-J) apparatus in the 1989 revision of these regulations. To determine the safety of an explosive in terms of toxic gas production, the Large Chamber Test attempts to simulate mine conditions and miners` exposure to toxic gases from explosives. The test is conducted by firing 1 pound of high explosive from a steel cannon into a closed steel chamber 1,354 cubic feet in volume. The detonation byproducts are mixed and drawn through a set of bubblers and impingers. The solutions are analyzed using wet chemistry methods to determine quantities of nitric oxide, nitrogen dioxide, ammonia, hydrogen sulfide, and sulfur dioxide. Quantities of carbon monoxide and carbon dioxide are determined using gas chromatography on vaccutainer grab samples. Toxic fumes data from experiments in themore » Large Chamber, Bichel gauge, C-J apparatus, and several mines show that the Large Chamber more closely simulates mine conditions. Although the hardware is specific to the USBM, the procedure presented demonstrates an economical method of toxic fumes analysis using basic instrumentation and equipment.« less