【国外标准】 Standard Guide for Sampling Spray Polyurethane Foam and Coating in Roofing

4.1 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.4.2 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 D1621 and D1622. 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.4.3 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 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 nonconformance with the standard1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.