I am proposing a short cooking demonstration with a propane torch inside a closed (no windows) conference room with ducted air conditioning.

For this to be a safe demonstration - I am concerned to have the CO2 levels to be 1000ppm max.

Here are my calcs + assumptions:

• Room is 6m x 4m x 2.4m = 57.6m3
• Assume 400ppm CO2 initial concentration in the air
• Target max CO2 concentration of 1000ppm
• Ducted AC system brings in fresh air to keep CO2 @ 400ppm with a handful of occupants in the room
• Room temperature 25C

1kg of CO2 @ 25C = [22.7 mol x 0.0821 x (273 + 25)] / 1000 = 0.56m3

CO2 weight per m3 air @ 400ppm = (0.0004m3 x 1000) / 0.56 = 0.72g

Weight of CO2 @ 400ppm in entire room = 57.6m3 x 0.72g = 41.4g

Target max CO2 @ 1000ppm = 57.6m3 x 0.72g x 2.5 = 103.6g

Combustion of C3H8 (Propane) - C3H8 + 5O2 = 3CO2 + 4H2O, ie. 44g propane + 160g oxygen = 132g CO2 + 72g H2O

1g of combustion of Propane = 3g CO2 produced (decrease of O2 concentration is negligible)

Maximum burnable propane = (103.6g - 41.4g) / 3 = 20.7g

Would I be correct to assume (I understand other variables can be at play) - that if I burn 20g of propane using a torch inside this room - I can keep the CO2 levels safe for the occupants in the room?

On safe side take a electrical fireplace.