You just need to breath N₂ while purging the CO₂ at the same time, it's not rocket science. That mask it's just one way of doing it using a constant flow solution, which looks interesting coz it has an one-way valve for CO₂ exhalation.
The absolute best way of doing it is with an
SCBA (the system used by firefighters), or
SCUBA (the system used by divers) on PP (Positive Pressure, which works the same as an SCBA).
SCBA is the Gold Standard in the industry to breath a gas from a cylinder while being completely isolated and protected from the external gas, which is exactly what is needed to CTB. The system works using a regulator and a demand valve that maintains a positive pressure inside the mask at all times (some millibars over ambient pressure) which creates a perfect seal (physically impossible for the external air to enter the mask). The demand valve only pumps the gas that is needed, which dramatically reduces the gas consumption vs an ExitBag that has a constant 15 LPM flow.
With this system even if you insert your pinky (lol) inside the mask you won't break the seal, the demand valve will just increase the pressure accordingly to maintain a positive pressure (this would increase the gas usage tho).
NP (Negative Pressure) SCUBA
has also been used to CTB but it is a suboptimal implementation, since the NP demand valve requires an inspiratory effort to open (the rest of the time is closed, like during exhalation) and the seal is totally dependant on the mask->skin contact surface being airtight (which usually is). Most SCUBA demand valves are NP instead of PP as NP is the preferred type of experienced divers. PP SCUBA gear is commonly expensive, with the mask+embedded demand valve usually being a bit under $1k.
This method was used to assist suicide by one of the prominent figures of the forum (
@LetzteAusfahrt).
The SCBA/PP-SCUBA method is the evolution of the ExitBag. It was invented by a pioneer called Scrooge who
published it on the
Dignitas Forum on 09/March/2010. 3 years later it was
documented in the medical literature the first CTB following his guide. The next stage in the evolution is
the Sarco, but it will have a
prohibitively expensive price.
There is currently only one source of equipment that sells an entire SCBA CTB Kit (the Canadian source), which also offers other constant flow solutions like the EEBD hood. All the components are 100% legal, like buying any other thing on the Internet. The equipment is expensive but the thing is as good as it gets in terms of CTBing. It is region-specific since every region has its own N₂ connection standard. This source at the moment has no competition in the market in terms of selling the entire thing put together ready to use. It would be interesting to see other sources joining this niche-market and start competing.
There are cheaper options like purchasing SCBA parts and using an air-to-nitrogen adapter if it's available in your region (like the [G 5/8" internal thread] to [W24.8 x 1/14" internal thread] that exists on EU), or adapting a typical N₂ pressure regulator to connect it to a demand valve. If somebody finds a
quick coupling adapter for the
plug-in nipple of the demand valve, to connect it to a conventional N₂ pressure regulator like the one
@Joarga used, it would be possible to implement a much cheaper setup.
) and skimmed through the rest. I don't want to contradict any statements made here or argue with anybody - just wanted to ask for advice / comments.
