The Old Ruminator
Well-known member
Curtain Chamber in Manor Farm was %4 CO2 this week and one caver described it as her worst ever trip. Other Mendip caves are currently affected.
The places being mentioned are not inhabited so persons exhaling CO2 is not a source. Obviously when you go into a passage you are exhaling some CO2 and then it depends upon the size of the passage, potential for drafts and breathing rate. The at rest breathing rate is between 12 and 20 breaths per minute, the tidal volume is around 1/2 litre and the level of CO2 in exhaled air is around 5% (see wikipedia respiratory system). So that means one breaths out 20 * 1/2 * 5/100 or half a litre per minute. So at one extreme if you have a large chamber with some air drafts, you will make no impact on CO2 level. But in an air bell of say 1m diameter hemisphere, that is 0.26m^3 or 260 litre, you can see it would only take around 20 minutes for the CO2 level to build up to 4%. (You may recall the Langstroth Pot incident where 3 people died in an air bell see https://www.brcc.org.uk/downloads/arch/archive20a.png and also the ...20b.png image.)2xw said:Bob, to what extent is their an input of exhaled CO2?
Have you got a instrument to that? If so could you PM me?mrodoc said:We are hoping to do some data logging in our dig at some stage to assess day to day fluctuations.
Leclused said:For your information, a flemish caver who currently lives in France (Ard?che) has developed a rugged CO2 meter for cavers.
http://lab.speleo.nu/co2vking.php
On his website you can also find information about other climate project in French caves.
BR
Dagobert