ASTM C1794 : 15

1.1 This test method defines a procedure to determine the water absorption coefficient of a material by partial submersion. The scope is to evaluate the rate of absorption of water due to capillary forces for building materials in contact with normal or driving rain above grade. The procedure is typically suitable mainly for masonry material, plaster, or a coating in combination with a substrate; but it can also be used for insulation materials. This test method is designed to be used only on homogeneous materials and does not apply to materials that are composites or non-homogeneous (for example, Faced Rigid Closed-cell Insulation). It is not within the scope of this standard to determine liquid uptake phenomena in below-grade applications. The water absorption coefficient is mainly used as an input datum for numerical simulation of the combined heat and moisture transport in building envelopes for design and forensic investigation purposes.

1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. However, derived results can be converted from one system to the other using appropriate conversion factors (see Table 1).

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.