Comment (1) of David Miller on FR Doc # 2011-18270

RG 1.91 Rev 1 includes a reasonable upper bound to the blast energy potentially available based on experimental detonations of confined vapor clouds of 240 percent mass equivalence by reference to Eichler, 1977. The current draft regulatory guide uses current industry practice but eliminates the thumb rule and the reference. The regulatory analysis could be improved by providing more information regarding the potential impact of dropping the guidance of 240 percent.