ASTM D4702-07

This practice addresses quality assurance criteria for operation of a mechanical coal-sampling system in accordance with Practice D 7256/D 7256M, Practice D 2013, and Practice D 4916. It provides recommendations for performance monitoring, inspection, and maintenance, which are necessary in maintaining a sampling system’capability to consistently obtain a representative sample.

1.1 This practice is applicable to cross-belt, falling-stream, and auger sampling systems.

1.2 Spacing of increments pertains to the kind of interval between increments. Intervals can be defined in quantitative terms, such as units of time or mass, or in terms of position over the lot.

1.2.1 Spacing of Increments for Cross-Belt and Falling-Stream Samplers—Cross-belt and falling-stream type mechanical sampling systems take increments based on time, either at fixed time intervals or at random times during a fixed time strata. Some falling-stream samplers can take increments based on equal mass of coal sampled as determined by scales. The sections of this practice that pertain to cross-belt and falling-stream samplers describe procedures for only time-based sampling systems. This time-based inspection guideline will satisfy most criteria for mass-based or combination mass-based and time-based sampling systems. If there are items that are not covered, the inspector should refer to the manufacturer's literature.

1.2.2 Spacing of Increments for Auger Sampling—The spacing of increments collected by auger sampling systems is defined in terms of position over the lot.

1.3 It is essential that the inspector have the documentation listed in Section 2 of this practice when conducting an inspection.

1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.5 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. For a specific hazard statement, see Section 5.