M. Iida, T. Matsunaga, Y. Nakayama, and Katsumi Tanaka
[J. of the Japan Explosives Society, Vol.58, No.6, pp.601-604, 1997]

Air blast experiments for black powder(grain) with charge weight of from 50kg to 400kg and for cast TNT charges as standard explosives were conducted to obtain the blast properties and TNT equivalence of black powder. Data were acquired by piezoelectric gages and lead-plate blastmeters, and TNT equivalence of black powder was determined on the basis of measured static peak overpressures. Resulted TNT equivalence increased when the explosion mass of black powder increased, and reached about 40% of the charge at the explosion with 400kg in weight.