GPTC GUIDE FOR GAS TRANSMISSION AND §192.721 DISTRIBUTION PIPING SYSTEMS: 2009 Edition SUBPART M

282 3 SPECIAL LOCATIONS

Places or structures where physical movement or external loading may cause leakage or failure should be identified by the operator based on knowledge of the system characteristics and problem areas. Where a main or its support structure is constructed and maintained to resist movement and external loading, the operator may determine that special-location patrols are not required.

Areas where an operator should consider performing increased patrol activity include the following. (a) Bridge crossings. (b) Aerial crossings. (c) Unstable river banks. (d) Exposed water crossings. (e) Areas susceptible to washout. (f) Landslide areas. (g) Areas susceptible to earth subsidence, such as mines and landfills. (h) Tunnels. (i) Railroad crossings. (j) Attachments to buildings or other structures. (k) Facilities or support structures that require maintenance, until repaired.

4 REPORTS

Patrol reports should indicate hazardous conditions observed, corrective action taken or recommended, and the nature and location of any deficiencies.



## §192.723 Distribution systems: Leakage surveys. [Effective Date: 07/14/04]

(a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control program must be determined by the nature of the operations and the local conditions, but it must meet the following minimum requirements: (1) A leakage survey with leak detector equipment must be conducted in business districts, including tests of the atmosphere in gas, electric, telephone, sewer, and water system manholes, at cracks in pavement and sidewalks, and at other locations providing an opportunity for finding gas leaks, at intervals not exceeding 15 months, but at least once each calendar year. (2) A leakage survey with leak detector equipment must be conducted outside business districts as frequently as necessary, but at least once every 5 calendar years at intervals not exceeding 63 months. However, for cathodically unprotected distribution lines subject to §192.465(e) on which electrical surveys for corrosion are impractical, a leakage survey must be conducted at least once every 3 calendar years at intervals not exceeding 39 months.

[Amdt. 192-43, 47 FR 46850, Oct. 21, 1982; Amdt. 192-70, 58 FR 54524, Oct. 22, 1993; Amdt. 192-71, 59 FR 6579, Feb. 11, 1994; Amdt. 192-94, 69 FR 32886, June 14, 2004 with Amdt. 192-94 Correction, 69 FR 54591, Sept. 9, 2004]GPTC GUIDE FOR GAS TRANSMISSION AND §192.723 DISTRIBUTION PIPING SYSTEMS: 2009 Edition SUBPART M

283 GUIDE MATERIAL

1 FREQUENCY

1.1 Business districts

. In determining business districts, the following should be considered. (a) Areas where the public regularly congregates or where the majority of the buildings on either side of the street are regularly utilized for industrial, commercial, financial, educational, religious, health, or recreational purposes. (b) Areas where gas and other underground facilities are congested under continuous street and sidewalk paving that extends to the building walls on one or both sides of the street. (c) Any other area that, in the judgment of the operator, should be so designated.

1.2 Minimum requirements

. The minimum frequency for leakage surveys is established by §192.723(b).

1.3 Increased frequency

. Consideration should be given to increased frequency for leakage surveys based on the particular circumstances and conditions. Surveys should be conducted most frequently in those areas with the greatest potential for leakage and where leakage could be expected to create a hazard. Factors to be considered in establishing the frequency of leakage surveys include the following. (a) Piping system. Age of pipe, materials, type of facilities, operating pressure, leak history records, and other studies. (b) Corrosion. Known areas of significant corrosion, or areas where corrosive environments are known to exist. Cased crossings of roads, highways, railroads, etc., due to susceptibility to unique corrosive conditions. (c) Piping location. Proximity to buildings or other structures and the type and use of the buildings. Proximity to areas of concentrations of people. (d) Environmental conditions and construction activity. Conditions that could increase the potential for leakage or cause leaking gas to migrate to an area where it could create a hazard, such as the following. (1) Weather conditions. (2) Areas of known frost heaving. (3) Wall to wall pavement. (4) Porous soil conditions. (5) Areas of high construction activity. (6) Trenchless excavation activities (e.g., boring). (7) Blasting. See Guide Material Appendix G-192-16. (8) Large earth moving equipment. (9) Heavy traffic. (10) Unstable soil or areas subject to earth movement. (e) Other. Any other condition known to the operator that has significant potential to initiate a leak or to permit leaking gas to migrate to an area where it could result in a hazard, such as the following. (1) Earthquake. (2) Subsidence. (3) Flooding. (4) An increase in operating pressure. (5) The extensive growth of tree roots around pipeline facilities that can exert substantial longitudinal force on the pipe and nearby joints.

1.4 Special one-time surveys

. Special one-time surveys should be considered following exposure of the pipeline to unusual stresses (e.g., earthquakes, blasting) or trenchless installation of foreign buried facilities that cross gas pipelines.