I was involved in a project in a previous job and as part of that I needed to find out exactly how loud detonators are
People have no idea how difficult/sophisticated noise measurement is.
A detonation (like when the can of a det bursts) has an instantaneous pressure pulse, (which is a "noise," but almost impossible to measure absolutely exactly.) Then you have a sound pressure level measured by what normal microphones can respond to, missing the highest instantaneous pressure unless they have been designed to capture that - in which case they can't measure the noise in a way that correlates with any other noise measurement. There are lots of measures which do their best to produce a useful number, see the frequency weighting section on wikipedia
https://en.wikipedia.org/wiki/Sound_level_meter. This seems to say that an instantaneous SPL is now a reality.
Well, that's what they told me. You agree with me, however, that the rail industry in the UK currently has no speciftied standard for the volume of the explosion made by an exploding detonator (as in a "it must produce a sound pressure of X decibels measured a Y metres" sort of thing)?
No I don't, I have absolutely no idea about the current standard.
I just said that BR (in the 1980s/90s) had a very detailed spec of
exactly how dets had to be when delivered - and hence how they should be made. And that people making up "modern" standards (consultants being paid to produce guff in the modern style) often don't really understand either the science or the industry they are about to lock into a straight jacket.
I also said that I don't think that what we in the UK call Sound Pressure Level (SPL) in deciBels, dB, at whatever distance in air (and whether A-rated - mimicking
the human ear's threshold of hearing at different frequencies, or linear, or C-weighted) is particularly relevant to the detection/hearing of dets on the footplate...
A further problem is that hearing protection almost always uses A-weighting, whetre the human threshold of hearing is subtracted from the actual SPL at each frequency...