4.1 Stress is applied as pressure over the area of the flatjack. In the case of multi-wythe masonry, stress is estimated only in the wythe in which the flatjack is inserted. Stress in other wythes may be different.

1.1 This test method covers the determination of the average compressive stress in existing unreinforced solid-unit masonry (see Note 1). This test method concerns the measurement of in-situ compressive stress in existing masonry by use of thin, bladder-like flatjack devices that are installed in cut mortar joints in the masonry wall. This test method provides a relatively non-destructive means of determining masonry properties in place.

Note 1: Solid-unit masonry is that built with stone, concrete, or clay units whose net area is equal to or greater than 75 % of the gross area.

1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.3 This standard does not purport to address all of the safety concerns, 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.