How about the plastic hose - is it fire proof and what chemicals are released when it melts ?
You use it for boundary cooling, not at the scene of the fire. If it does melt and release anything it's not that much of a worry as everyone will be on EBS and as soon as safe to do so you snort ventilate. As soon as the mass spec and draegers say the atmosphere is back in spec you remove EBS. Plus if there's a fire there's far more shit in the atmosphere than a melting hose will kick out.