【国外标准】 Standard Practice for Representative Field Sampling of Traffic Paints

5.1 For quality assessment and/or approval for use of traffic paint stored in the field, it is often necessary to obtain a representative sample for testing. Correct sampling of traffic paint is a skilled operation, and if not properly conducted with the right equipment and procedures, a sample may inadvertently fail one or more specification tests when evaluated by a testing laboratory. Among the test results that could be affected are solids content, resin content, TiO2 content, heat-age stability, freeze-thaw stability, and dry time. Any of these could inadvertently result in non-approval or penalties.1.1 This practice covers procedures for obtaining representative field samples of mixed or unmixed waterborne, solventborne, or other liquid traffic paints, including two component reactive materials from drums, totes, or machine striping tanks. Traffic paint samples are often taken from storage containers in the field by paint suppliers or government agencies for laboratory testing to determine product quality and/or for approvals prior to striping. It is important that the samples taken are “representative” (have a composition reflecting the overall composition in the container). Although traffic paints can remain homogeneous for weeks or months, some will stratify over time and become non-homogeneous. Obtaining a representative sample can be challenging particularly in a field environment. The desired method for obtaining a liquid sample is to thoroughly mix the sample until homogeneous and then sample the mixture from the top. If complete mixing can’t be verified then an alternative practice is to obtain a sample using a liquid tube sampling device. These devices have the ability to capture a top-to-bottom core of paint from the container. Inner or outer rod tube samplers are recommended for sample extraction. The inner rod tube sampler is the preferred sampler.1.2 The practice selected for representative sampling should have written agreement between the parties providing the product and those testing the product.1.3 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.1.4 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.1.5 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.