Am not agreeing or disagreeing with following - a UK noise control company’s advice to EMPLOYERS on matters relating to employees with hearing aids in very noisy environments:
Hearing protection and hearing aids — The Noise Chap | Audiometry and Noise Assessments
Basically the noise control/abatement company says that modern hearing aids with amplification limits that are worn IN THE EAR under ear muffs are OK. The ear muff limits sound exposure. The hearing aid won’t amplify past its own set upper amplification limits.
But the advice is that BTE modern hearing aids are to be regarded with suspicion as they may block ear muff protection. I would think if one could find ear muffs that are comfy to wear and had big enough cups to fit over BTE bodies, you could then document that the hearing protection worked (well enough) with REM in the ear canal near the ear drum. The cups of my Surface Pro headphones fit well over my RIC ReSound Quattro’s and in fact, the main leakage, if any, is from the frames of my glasses preventing a good seal near my temples. (an interesting corollary topic relative to HA’s and hearing protection). Since I’m not bothered with the Surface Headphone cups pressed against my glasses frames because of the squishy cups, maybe you should try something similar. Rather than ordering from Amazon, maybe if you can safely do so w.r.t. COVID and masking, you should go to a Best Buy or similar and try on headphones on display, see how comfy they are and what their NRR, if any is?
Perhaps there should be no “%” sign after 27. Maybe what you mean to say is that OSHA is saying your hearing protection must have a NRR of at least 27 for each ear (with NO % sign involved?). If you are already at ~85 dB average, though, already allowable by OSHA for an 8-hour shift, with only 3 dBA reduction required to reach 82 dB average, allowable for a 16-hour shift, that doesn’t make sense, AFAIK. But maybe you are at 85 dB only if you wear the ear protection recommended by or to your employer??
AND
How to Make Noise Reduction Earmuffs and Headsets More Comfortable - NoisyWorld