If I recall correctly the maximum Noise Reduction Rating (NRR) for earplugs and earmuffs is around 30db. You can combine the two for a slight increase in hearing protection but you still hit a limit because of bone vibration.
Is there PPE out there to go even further beyond this? Where would it be commonly used?
Couple years ago, I visited a historic grand prix that featured classic F1 cars. They also had open pits, so you could walk up and ask questions and literally stand next to the cars.
I was standing next to a 70’s F1 car when they performed an engine test. I was wearing thick, professional earplugs and the biggest Peltors you’ve ever seen. When they fired that thing up, I lasted all of five seconds before I walked out. At that point, it was no longer sound but sheer pressure. You could feel it in your chest.
As for how the mechanics do it? Easy, they’re all deaf as a post. Even the best earpro can’t prevent that kind of hearing damage, especially if that’s your chosen career. If you’re worried about good earpro not being enough, best advice is to put distance between you and the object/career path involved.
When I was in the Army they put us in a room with a jet engine bolted to a concrete block, and the exhaust routed outside of the building. They fired that thing up and it was overwhelming. My hearing is fucked up today, and I sometimes wonder how much of the damage was due to that demonstration. Standing near a fucking Howitzer without ear plugs when it was fired off probably didn’t help much either.
I wonder if there would be a way to counter that though. Maybe some kind of sound-focused bomb suit developed for a single profession?
I imagine most situations are avoidable with modern technology allowing us to do things remotely but perhaps there was something used historically or as part of a “because I can” experiment.
Space-suits must operate this way, if inadvertently…
The number of decibels at the rocket-nozzles is waaay higher than what it would be “at the top of the candle”, but … there’s pretty-much nothing in Nature as loud as those things are, except meteorites, maybe some volcanoes, being inside of lightning, etc…
I visited a top fuel dragster event once. It was insane to feel the pressure in my chest despite being a good 50-100m away from the cars.