Adequate coating thickness (mil thickness) is necessary to protect polyurethane foam from the effects of ultraviolet degradation. This guide outlines general procedures for sampling and measuring the coating thickness by using slit or core samples.

Thickness of individual lifts of sprayed foam will have a bearing upon foam stability. Core samples are used to determine foam thickness. Compressive strength and core density affect resistance to foot traffic and impact. Specimens from core samples are used to determine these properties using Test Methods D 1621 and D 1622. Visual examinations of core specimens also indicate the quality of adhesion of the coating and the foam, between foam lifts, and between foam and substrate.

Slit samples are used to visually examine the foam’s cell structure, the number of coating layers applied, dry film thickness of the coating, and coating adhesion.

1.1 This guide covers the removal of test specimens from spray polyurethane foam (SPF) roofing systems in the field for the purpose of examination of an existing system and/or quality assurance for new installations. It describes the types and purposes of sample cuts, visual inspection techniques, laboratory physical property tests, and repair of the core and slit sample holes.

1.2 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.