Here’s a reply from someone who staffs vessels with crews of 9, and who has also run a marine firefighting school for 27 years.
This answer is purely practical. It has nothing to do with standards organization. It comes from training using wood-burning fires in a three-deck tall 5,000 square foot simulator, and also doing training using exposure to ammonia. In other words, pretty realistic conditions.
I haven’t seen a beard to be much of a problem with SCBA use. The practical issue with beards is more length of time on-air; the positive pressure factor apparently does a good job of preventing smoke inhalation, but in doing so reduces on-air time.
So, we don’t have any regs re: beards and SCBAs.
Another remark from years of careful observation: when it comes to SCBA use, of far more concern than a beard is how much a guy smokes. A smooth-shaven 40 yo chain-smoker is of far more concern than a 25 yo bearded guy who doesn’t smoke. At best the smoker is going to burn through his air supply in a hurry, reducing his usefulness. At worst he’s going to be a medical emergency.
Why this fact isn’t talked about more in training circles always puzzles me.
Easy now…we’re dealing with SIRE after all. Let’s not give them more ammo. We’re going to have to present them with medical files, pulmonary and respiratory capacity exam results for each crew member, etc. JHAs stating that we considered the cardiovascular health of each person on the fire party, etc. It literally will never end with SIRE.