§ 761.250 Sample site selection for pipeline section abandonment.

This procedure is for the sample site selection for a pipeline section to be abandoned, in accordance with § 761.60(b)(5)(i)(B). (a) General. (1) Select sample collection sites in the pipeline section(s) by following the directions in paragraph (b) of this section. (2) Select the proper sampling position along the pipe by following the directions in § 761.247 (c) and (d). (3) Assure, by visual inspection, the absence of free-flowing liquids in the pipe by affirming no liquids at all liquid collection points and all ends of the pipeline section to be abandoned. (b) Selection sample collection sites. At a minimum, sample all ends of all pipeline sections to be abandoned in place. (1) If the pipeline section to be abandoned is between the pressure side of one compressor station and the suction side of the next compressor station downstream of the former gas flow, at a minimum, sample all ends of the abandoned pipe. (2) If the pipeline section to be abandoned is longer than the distance between the pressure side of one compressor station and the suction side of the next compressor station downstream of the former gas flow, divide the pipeline section, for purposes of sampling, into smaller pipeline sections no longer than the distance from the pressure side of one compressor station to the suction side of the next compressor station downstream of the former gas flow. Consider each of the smaller sections to be a separate abandonment and sample each one, at a minimum, at all ends. (3) Use the following procedure to locate representative sample collection sites in pipeline sections at points other than the suction and pressure side of compressor stations, or the ends of the pipeline section to be abandoned. (i) First, assign a unique identifying sequential number to each kilometer or fraction of a kilometer length of pipe within the entire pipeline section. (ii) Use a random number table or a random number generator to select each representative sample collection site from a complete list of the sequential identification numbers. (iii) Samples may be collected by removing any covering soil, cutting the pipe to gain access to the sampling location, and collecting the surface sample with the pipe in place, rather than completely removing the pipeline sections to collect the surface sample.