Re: impressive surefire demo on outdoor channel.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RollingThunder51</div><div class="ubbcode-body">CoryT,
You are correct and for fear of hyjacking the thread, I'll keep this short. From what I am reading, that is all about to change. Impulse is being lowered to the very same 85 dB threshold if the impulse occurs more routinely than once every four (4) hours in the work place. That would be twice within the standard 8 hour day. As we are all aware, impact by Osha for, say rivet guns and/or jack hammers have already required protection and both of those are below the 140 dB threshold. In short, rapid fire or full auto would be 10 dB higher than standing with your ears 30" from a jack hammer head (120 dB) going at it. All of us know that the 140 dB rating is a crock and that anybody that sits out there and beats out a steady beat will do big damage.
The returning numbers are telling the full story and there are at least two big projects that I am aware of that are commited to tackle this one head on. Why the change? Because the data is startling and disturbing, with nearly two thirds of returning vets from Britian having severe to permanent damage and, for the Americans, it is coming in as the #1 disability. My point is simply this, 140 dB isn't good enough for any manufacturer. Better than nothing? yes. Good, no and certainly not hearing safe. Its starts with suppression, well before POI, making a POI can is much easier than making a very quiet can with great POI repeatability. That is all I am saying.
I think it is great that Surefire has excellent POI results, I too would want anybody to meter the very can they are testing POI with. I'll go one further, dB tesing now will, I believe, migrate to duration of pulse as well. Pressure, duration, frequency, POI, etc., etc.
I'll stop within this thread, apologies.
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I would believe that basing a change in the hearing safe impulse noise level, based on the statistics of returning veterans would be skewed.
Why, because the majority of people have shot their weapons unsuppressed and there is exposure to heavier weapons, explosions, incoming fire etc.
I have fired thousands of rounds suppressed with weapons ranging from pistols to light machineguns and my hearing is normal.
It is good that there is current research on the impulse noise levels, exposure times etc. and discussion on what really is "safe", but it is fair to say that exposure to impulse SPLs of 126-138 dB ( the range in most suppressed centrefire weapons range ) than the level 155-160 dB level of unsuppressed centrefire weapons.
Could you disclose your occupation, do you work with suppressors?
Best Regards!
Tuukka Jokinen
Ase Utra sound suppressors
