Frequency of Leak Surveys. Each owner shall conduct a gas leak survey of a LPG pipeline system in accordance with the following schedule: At least once each calendar year, at intervals not exceeding 15 months, for a pipeline located in a business district or place of public assembly; At least once every 3 calendar years, at intervals not exceeding 39 months, for a pipeline made of cast iron, ductile iron, and cathodically unprotected steel; or At least once every 5 calendar years, at intervals not exceeding 63 months, for all other types of pipelines. Testing Methods. Each owner shall establish written procedures for conducting gas leak surveys as specified in this chapter. Acceptable methods for owners conducting gas leak surveys, as described in the GPTC Guide for Gas Transmission and Distribution Piping Systems, include: Subsurface gas detector survey, including bar hole surveys; Bubble leakage test for pipelines exposed to the atmosphere; or Pressure drop test. In addition to the acceptable methods listed in §B(2) of this regulation, other survey and test methods that have been tested and proven to be at least equal to the methods listed in §B(2) of this regulation and approved by the Commission may be used to meet the requirements of §B(1) of this regulation. A leak or leaks discovered by a gas leak survey conducted pursuant to this regulation shall be classified, and the appropriate action taken as described in the GPTC Guide For Gas Transmission and Distribution Piping Systems. Field Operations. An owner shall conduct a leakage survey on each new or replaced service line before the line is placed in service, but after backfilling and a reasonable period of gas pressurizing. After a leak repair, an owner shall conduct a gas leakage survey in accordance with §B of this regulation. Records of Leak Surveys. An owner shall maintain a record of each leak survey listing by location and date for the following: Number of leaks detected; Severity of each leak; and Action taken to repair each leak. An owner shall maintain the records required under §E(1) of this regulation as long as the segment of pipeline involved remains in service.