Noise attenuation of structures against impulses from large calibre weapons or explosions

The noise attenuation properties of solid structures, shooting shelters and ground barriers were studied against shots of heavy weapons such as 95 mm bazookas, 23 mm antiaircraft cannon and explosions of 1 kg trinitrotoluene (TNT). Massive and carefully constructed structures can attenuate the impulse noise of large calibre weapons or explosions by more than 30 dB when measured as the peak level and by more than 20 dB when measured as the exposure level. A typical type of closed structure (e.g. wooden building or shelter) was found to attenuate a peak level of more than 10 dB and an exposure level of more than 5 dB. Open structures or barriers were less effective — usually less than 5 dB in peak level attenuation — and therefore they have limited effect in noise control because attenuation of more than 20 dB is often needed.