I am rather different among knifemakers and firefighters in that I very rarely carry a knife. For the most part I am an incurable pragmatist and one of the grumpy old veterans on my department. I get a real chuckle out of the gung-ho rookies with a $1500 light bar on a $400 car and "No Fear!" stickers plastered on their window and helmet. I love to inspire fear in them, fear of 800+ feet of 2-1/2 in need of scrubbing after they got to play with it:3:. Hanging hose in the tower and doing reports is my way of allowing them to make up for standing around posing in the RIT team staging while we actually worked the scene. But I digress…
To help with an answer I need to really think about the things in a structure fire that could be handled with a knife and outside of a few entanglement issues with the SBCA, I am coming up short. Axes and haligan tools sure, but knives seem a little light for much of what we do in fires. I can see more applications in extrication and EMS situations, cutting seat belts, wires or other soft entanglements perhaps, but then you have the PR situation of flashing a knife around your patients. The ambulance personnel would probably take issue with you running a knife up a victims pant leg when they have safe little blunt nose scissors designed specifically for that.
If there were a safe practical fixed blade design for this, I would think along the lines of a diving knife. As both a firefighter and a diver I can see the most parallels in the safe use requirements here. SCUBA work or SCBA work both require bulky gear with lines and straps and harnesses that limit your mobility in atmospheres not conducive to normal human activity. I think a knife without a sharp point makes sense for the same reasons to both. A handle you can get your hands on and identify it as the knife, and which side the edge is on, without looking is a good idea. The sheath would be important, you want a very secure fastening that is also capable of quick release, but the sheath itself should be almost indestructible in containing the sharp blade parts. I may go stainless on the blade due to all the unimaginable crap turnout gear is exposed to.
There is one big difference from SCUBA to SCBA however, you can use any water resistant material you want for the handle or sheath on one while in the worst case scenario most materials will char or melt away on the other. A very attentive safety officer may not even allow an addition to the gear that would present a threat of igniting or spreading molten flammables on the user. We aren’t even allowed to use anything but special nomex thread to sew on the exterior of our bunkers.
I hope I was able to give a couple of pointers, but for the most part if a knife was really useful on a fire scene it would have many features that could make it much less useful as a hunting knife.
