This test method covers the quantitative determination of percent relative humidity above the surface of concrete floor slabs for field or laboratory tests.

Formerly under the jurisdiction of Committee F06 on Resilient Floor Coverings, this test method was withdrawn in December 2014. This standard is being withdrawn without replacement because the preliminary Precision and Bias was conducted on December 26, 2013 to March 3, 2014 by ASTM members. When tested over one sealed concrete slab with the surface prepared as described in the latest approved draft of F2420, the results showed that each hood/probe took about 49 days to get within approximately 2 % of its last reading taken after 70 days. That said, at 70 days the six different hood/probe assemblies used had a 9 % difference between them. These results clearly show that even after 70 days they would not be accepted by flooring manufacturers as a go/no-go test method for installing resilient flooring. In addition, even as a test method for investigating installation failures it shows to be inconclusive at 70 days so it has no real value to the industry. The fact that there is an ASTM test method is one reason that other countries use it even though they have never performed any Precision and Bias themselves. Withdrawing this document seems reasonable as there appears to be little value to the industry.

Moisture permeating from concrete floor slabs affects the performance of flooring systems such as resilient, wood, textile floor coverings and resinous coatings. Manufacturers of such systems generally require humidity/moisture testing be performed before installation over concrete floor slabs. The measurement of relative humidity (RH) directly above the porous surfaces of a floor slab is one such method.

Excessive moisture in or emitting from floor slabs after installation can cause floor covering system failures such as delamination, bonding failure, deterioration of finish flooring and coatings, and microbial growth.

The surface RH Hood (relative humidity) test method is intended to quantify the relative humidity condition that exists at the surface of a floor slab to which a floor covering or coating shall be applied. Results indicate moisture content conditions at the time of the test, as moisture movement within the slab is dynamic. See A1.4 for reference to some methods of determining moisture/humidity levels in a concrete slab.

1.1 This test method covers the quantitative determination of percent relative humidity above the surface of concrete floor slabs for field or laboratory tests.

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. Some specific warnings are given in Section 7.