As you may or may not be aware, there has been a lot of attention brought to the face pieces that we wear recently. There have been several close calls and LODDs that have resulted directly from a catastrophic failure of the facepiece the the firefighter was wearing while in an IDLH. Now before you start throwing rocks, it has not been just one manufacturer, or one style of face piece. There are documented failures across all brands.
If that doesn't scare you it should. basically what they have found is that no face peice is immune from it, and there aren't really sure what heat is causing them to fail. There are some additional studies going on right now about it, but the preliminary opinions that I have heard in various presentations are that our gear is too good. Too good.....What the hell do you mean by that? you may ask. I'm telling you, that the gear that is out there right now is far superior and safer to the canvas jackets and hip boots of old. But if you ask an old head, how did you guys feel heat? He would reply, well why don't you guess, you knew it was hot when your family jewels started to light up, then you knew it was time to go. We don't have that luxury (not that is something I wish we had), so we wait until we feel heat through our gear, which much of the time never happens. So then that heat attacks our whole ensembleand then the weakest link shows up, usually the facepiece. Not exactly comforting, considering that if it fails we can't breath, not a good thing.
In fact, in two of the four experiments that NIST conducted the facepieces failed, here is one of them: