Thread: Suppressor effectiveness - Think about this!

Yes the focus is on continuous but there is a specific section on impulse noise in 3.2 ceiling limit:

"The generally accepted ceiling limit of 140 dB peak SPL for impulsive noise is based on a report by Kryter et al. [1966]. Ward [1986] indicated that "this number was little more than a guess when it was first proposed." To date, a proposal for a different limit has not been supported. Henderson et al. [1991] indicated that the critical level for chinchillas is between 119 and 125 dB; and if a 20-dB adjustment is used to account for the difference in susceptibility between chinchillas and humans, the critical level extrapolated for humans would be between 139 and 145 dB. Based on the 85-dBA REL and the 3-dB exchange rate, the allowable exposure time at 140 dBA is less than 0.1 sec; thus, 140dBA is a reasonable ceiling limit for impulsive noise."

In the absence of any other data, this looks to be the only source that actually provides a guide for impulse noises between the 125 and 140 dBA ranges. Shooters will regularly experience levels in this range suppressed or with single layer of hearing protection for non magnum centerfire rifles. Braked and magnum shooters will exceed these limits with a single layer of hearing protection.

If there is more info available or better guides, I would like to see them.

Originally Posted by ODL

.. Based on the 85-dBA REL and the 3-dB exchange rate, [B]the allowable exposure time at 140 dBA is less than 0.1 sec; ..

In all the impulse literature I've read, I can't say I've seen detailed focus on time/energy integration. The tone of that sounds rather speculative.

Those refs quoted are very familiar to me- I did a Masters thesis on noise induced hearing loss in 1991 and most of the literature wasn't fresh even then.