Nocturna666
Member
- Aug 26, 2025
- 77
Hey, I have some more basic questions that I belive to already know if anyone can confirm and give some advice that would be nice. does anyone know exactly what it means to pre fill a scba mask like gas monkey talks about it in his post? I have a scba with a purge button that lets through free flow when turned on. I assumed it pertains to that and filling for a few seconds the mask with nitrogen before taking your last exhale and inhale. The scba being used is one where it's breath on demand with the first inhale. Secondly I just read the post here about turning the cylinder valve all the way on to get maximum flow but why do most scba users in the professional field say to turn completely on then back a bit? Lastly is with the method you can't have air into the mask but there is always going to be a little leftover from before you put he mask on so…how does this not impact the performance of scba adequately causing ctb?
