I would check with your local codes people first. If no code can be identified determine an equivalent indoor environment and use the recommended exchange rate.
The equation to calculate exchange rates is:
q = n V
where:
n = Change rate time (h^-1) hours
v = Volume to be exchanged (ft^3, m^3)
q = Air suppler rate (ft^3/h, m^3/h)
h = Hours