【国外标准】 Standard Practice for Sampling Pitch

4.1 Sampling is as important as testing. If the sampling is improperly done, the sample of the material will be in error, and the analysis will not represent the true properties of the material, and it may be impossible or impracticable to take another sample; whereas, if the sample is properly taken and the analysis is in error, another analysis can readily be made of the original sample.4.2 Samples may be taken for either of the following two purposes:4.2.1 To represent as nearly as possible an average of the bulk of the materials sampled, or4.2.2 To ascertain the maximum variation in characteristics which the material possesses.4.3 A good sampling plan has the following characteristics:4.3.1 It protects the consumer against the acceptance of a bad batch of material.4.3.2 It protects the producer against the rejection of a good batch of material.4.3.3 It gives long-range protection to the consumer.4.3.4 It encourages the producer to keep his process in control.4.3.5 It minimizes the cost of sampling, inspection of testing, and administration.4.3.6 It provides information concerning the quality of the product.4.4 Sampling Integrity—When one takes a sample, one is attempting to represent a batch or lot of material with that sample. Different forms of pitch, and pitch in different types of containers, need to have different sampling plans and appropriate sampling equipment. Each sampling plan should be designed so that it accomplishes its objective, which is to ascertain the characteristics or quality of a batch or lot of material.1.1 This practice covers procedures for sampling pitch at points of manufacture, storage, and delivery.1.2 The values stated in SI units are to be regarded as standard. The values in parentheses are for information only.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific warning statements are given in Section 11.1.4 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.