1.1 This test method describes a standardized technique for measuring air-leakage rates through a building envelope under controlled pressurization and de-pressurization.

1.2 This test method 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.

1.3 The proper use of this test method requires a knowledge of the principles of air flow and pressure measurements.

1.4 This test method is intended to produce a measure of air tightness of a building envelope. Because of differences between natural load and test conditions, however, such measurements cannot be interpreted as direct measurements of air change rates that would occur under natural conditions.

1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements see Section 7.