The problems associated with designing effective silencers for suppressing noise from high‐pressure gas blowoffs differ somewhat from those associated with jet aircraft noise suppression because of the high expansion experienced by the gas as it is reduced to atmospheric pressure. Using a combination of aerodynamic and acoustic theory it is possible to calculate the flowing conditions which exist in a silencer and then to correlate these with noise regeneration at the silencer exhaust. Similarly, the effects of silencer internals on attenuating noise introduced into the vessel can be approximated on the basis of field tests and acoustic theory for a wide range of operating parameters. Using the techniques discussed in this paper, both the noise transmitted through a silencer and that regenerated at its exhaust can be approximated, and the over‐all noise reduction characteristics of a silencer design can thereby be anticipated through the use of the analytical techniques or design charts presented.