Coblentz C.W. Achenbach P.R.
Bibliographic info:
ASHRAE trans vol 69 p358-365

Gives measurements of air infiltration made in ten houses in Indiana using helium as a tracer gas. Assumes linear dependence of infiltration rate on temperature difference and wind velocity and calculates infiltration rate per unit crack length. Change rates ranged from about 0.6 to 1.5 changes per hour.