You don’t even need that. Just a decent dust mask that seals over your mouth and nose that has an exhalation port on it, with the nitrogen inlet fitted in place of the dust cartridge. You need a dust mask that has a one way flapper valve over the inlet, which most do.
Here’s an experiment I did as an emergency fresh air kit: Fill a large wheelie bin garbage bag with air and duct tape it closed over a 1 inch pipe. Attach the pipe in place of the dust cartridge with duct tape. Put the mask on and breath normally. The bag will deflate over about 15 minutes or so, depending on the size. I noticed no breathing distress like I was getting co2 buildup.
If you fill the bag with nitrogen instead of air you have a death machine for $15 in parts. 15 minutes is plenty of time.
You don’t even need that. Just a decent dust mask that seals over your mouth and nose that has an exhalation port on it, with the nitrogen inlet fitted in place of the dust cartridge. You need a dust mask that has a one way flapper valve over the inlet, which most do. Here’s an experiment I did as an emergency fresh air kit: Fill a large wheelie bin garbage bag with air and duct tape it closed over a 1 inch pipe. Attach the pipe in place of the dust cartridge with duct tape. Put the mask on and breath normally. The bag will deflate over about 15 minutes or so, depending on the size. I noticed no breathing distress like I was getting co2 buildup. If you fill the bag with nitrogen instead of air you have a death machine for $15 in parts. 15 minutes is plenty of time.