I've heard that purging the 3D printer with e.g. CO2 gas is something that you can do to improve layer adhesion. It should be sufficient to prevent fires also? Seems most plastics have a limiting oxygen concentration of around 16%. Purging from 21% down to, say, 15% requires that one adds 40 L of CO2 (at STP) to dilute a 100L chamber. Your typical 2.6 kg small CO2 bottle that people use for home-brew beer kegs would last for at least 35 fillings.
interesting thought but it's hard to seal up a vessel for any length of time. you could perhaps do a positive pressure vessel that slowly leaks from inside to out. (this is a common tactic in clean rooms with purified air a psi or two more pressurized than the hallways so the clean air always flows out to the hall.) not sure what the effects of leaking CO2 into your room would have though.
