Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Q&A

Post History

77%
+5 −0
Q&A Could a high-pressure, low oxygen atmosphere reduce fire risk while still being breathable?

Your intuition is correct. Let's suppose that at STP, a human needs to breathe 1L of O2 in 200 minutes. That's 1.43g of gaseous oxygen. If the pressure is raised to 5 bar, a human still needs 1.43g...

posted 3y ago by dsr‭

Answer
#1: Initial revision by user avatar dsr‭ · 2022-02-22T00:49:40Z (almost 3 years ago)
Your intuition is correct. Let's suppose that at STP, a human needs to breathe 1L of O2 in 200 minutes. That's 1.43g of gaseous oxygen. If the pressure is raised to 5 bar, a human still needs 1.43g of O2 -- but it will only take up 0.2L of volume, and the other neutral gas mass will have to increase as well.

Similarly, a fire that consumes 143g of O2 and 90g of powdered aluminum will use those proportions regardless of whether the O2 is mixed in a higher or lower pressure of neutral gas -- the gating factor is how fast the oxygen can come in contact with the aluminum.