# What kind of leak rates do modern habitat modules have?

I thought I was going to be able to answer this question for myself, after seeing the paper Determination of On-Orbit Cabin Air Loss from the International Space Station (ISS). But it turned out that it is pay-walled. I don't care about the paper, I just want a number.

Let's say that you were planning a long term interplanetary manned mission, so you know the volume in $m^3$ of space filled with breathable air. During the long leg of the flight, there will be no EVA or docking so the simplifications mentioned in that paper's abstract would be relevant. What kind of number for leak rate in terms of $\frac{kg}{s}$ or $\frac{m^3}{s}$ per unit volume might be anticipated? You could combine those units for ultimate units of $\frac{kg}{m^3 s}$ or just $\frac{1}{s}$. The latter unit would simply represent what fraction of the total volume is lost per unit time.