Full-face vs. Half-face

Posted by Terry Mcadams on Nov 29, 2004

Friends on the forum:

Last week a thread drifted off point and onto the subject of respirators, specifically the usefullness of full-face respirators to minimize the eye exposure pathway to epoxy vapors and dusts, as well as the other chemicals we use in boatbuildling. I'm not an expert on respirators (folks like industrial hygienists and safety engineers are), but I do use them in my work and have had extensive training on their selection and use. Anyhow, I just wanted to reprint a posting I sent to LeeG so y'all could see it. Kindly consult sources like NIOSH or respirator manufacturers for more detailed and up-to-date information.


Anyhow, the problem may have been the fit. Full face respirators are tricky to fit right. You can always do the quicky-at-home fit test of donning the mask, tightening the straps (evenly) then covering the cartridges with your hands while you inhale. This is a fair, seat-of-the pants way to fit test and I always do it before I don my mask. Problem is, in use while breathing normally, the mask seal will be looser and get looser as the straps loosen and/or you start moving around your jaw. This is where a qualitative/quantitative fit test helps. The problem with that is it may indicate you need a different brand of respirator, (3M, MSA, Scott, e.g.) as they all fit differently.

Other problems can be failure to clean the mask and store it in a sealed bag (which can increase interior contamination and reduce cartridge life) and not changing the cartridges frequently. The smell test for cartridges is not adequate and they should be changed daily for full-day use. This can get expensive, but worth it if you're doing a lot of epoxying in a confined space.

So the full-face is not a panacea for exposure related problems, but, in my opinion, still far better than a half-face for many and probably most exposures.

good luck