ISO 9972:1996

Thermal insulation -- Determination of building airtightness -- Fan pressurization method

This International Standard specifies the use of mechanical pressurization or depressurization of a building or building component. It describes techniques for measuring the resulting air flow rates at given indoor-outdoor static pressure differences. From the relationship between the air flow rates and pressure differences, the air leakage characteristics of a building envelope can be evaluated.

This International Standard is applicable to small temperature differentials and low-wind pressure conditions. For tests conducted in the field, it must be recognized that field conditions may be less than ideal. Nevertheless, strong winds and large indoor-outdoor temperature differentials should be avoided. The proper use of this International Standard requires a knowledge of the principles of air flow and pressure measurements,

This International Standard is intended for the measurement of the airtightness of building envelopes of single-zone buildings. For the purpose of this International Standard, many multi-zone buildings can be treated as single-zone buildings by opening interior doors or by inducing equal pressures in adjacent zones.

This International Standard is intended for the measurement of the airtightness of buildings and building components in the field. It does not address laboratory evaluation of air leakage through individual components. The results of the field measurements are not intended to characterize the air leakage of an isolated component but of the component and its junction with the building envelope under given conditions of installation. Therefore, the results from field tests of component airtightness may not be in agreement with the results from laboratory tests.