Section 192.179 - Transmission line valves(a) Each transmission line, other than offshore segments, must have sectionalizing block valves spaced as follows, unless in a particular case the Administrator finds that alternative spacing would provide an equivalent level of safety: (1) Each point on the pipeline in a Class 4 location must be within 21/2 miles (4 kilometers)of a valve.(2) Each point on the pipeline in a Class 3 location must be within 4 miles (6.4 kilometers) of a valve.(3) Each point on the pipeline in a Class 2 location must be within 71/2 miles (12 kilometers) of a valve.(4) Each point on the pipeline in a Class 1 location must be within 10 miles (16 kilometers) of a valve.(b) Each sectionalizing block valve on a transmission line, other than offshore segments, must comply with the following:(1) The valve and the operating device to open or close the valve must be readily accessible and protected from tampering and damage.(2) The valve must be supported to prevent settling of the valve or movement of the pipe to which it is attached.(c) Each section of a transmission line, other than offshore segments, between main line valves must have a blowdown valve with enough capacity to allow the transmission line to be blown down as rapidly as practicable. Each blowdown discharge must be located so the gas can be blown to the atmosphere without hazard and, if the transmission line is adjacent to an overhead electric line, so that the gas is directed away from the electrical conductors.(d) Offshore segments of transmission lines must be equipped with valves or other components to shut off the flow of gas to an offshore platform in an emergency.(e) For onshore transmission pipeline segments with diameters greater than or equal to 6 inches that are constructed after April 10, 2023, the operator must install rupture-mitigation valves (RMV) or an alternative equivalent technology whenever a valve must be installed to meet the appropriate valve spacing requirements of this section. An operator seeking to use alternative equivalent technology must notify PHMSA in accordance with the procedures set forth in paragraph (g) of this section. All RMVs and alternative equivalent technologies installed pursuant to this paragraph (e) must meet the requirements of § 192.636 . The installation requirements in this paragraph (e) do not apply to pipe segments with a potential impact radius (PIR), as defined in § 192.903 , that is less than or equal to 150 feet in either Class 1 or Class 2 locations. An operator may request an extension of the installation compliance deadline requirements of this paragraph (e) if it can demonstrate to PHMSA, in accordance with the notification procedures in § 192.18 , that those installation compliance deadlines would be economically, technically, or operationally infeasible for a particular new pipeline.(f) For entirely replaced onshore transmission pipeline segments, as defined in § 192.3 , with diameters greater than or equal to 6 inches and that are installed after April 10, 2023, the operator must install RMVs or an alternative equivalent technology whenever a valve must be installed to meet the appropriate valve spacing requirements of this section. An operator seeking to use alternative equivalent technology must notify PHMSA in accordance with the procedures set forth in paragraph (g) of this section. All RMVs and alternative equivalent technologies installed pursuant to this paragraph (f) must meet the requirements of § 192.636 . The requirements of this paragraph (f) apply when the applicable pipeline replacement project involves a valve, either through addition, replacement, or removal. The installation requirements in this paragraph (f) do not apply to pipe segments with a PIR, as defined in § 192.903 , that is less than or equal to 150 feet in either Class 1 or Class 2 locations. An operator may request an extension of the installation compliance deadline requirements of this paragraph (f) if it can demonstrate to PHMSA, in accordance with the notification procedures in § 192.18 , that those installation compliance deadlines would be economically, technically, or operationally infeasible for a particular pipeline replacement project.(g) If an operator elects to use alternative equivalent technology in accordance with paragraph (e) or (f) of this section, the operator must notify PHMSA in accordance with the procedures in § 192.18 . The operator must include a technical and safety evaluation in its notice to PHMSA. Valves that are installed as alternative equivalent technology must comply with §§ 192.634 and 192.636 . An operator requesting use of manual valves as an alternative equivalent technology must also include within the notification submitted to PHMSA a demonstration that installation of an RMV as otherwise required would be economically, technically, or operationally infeasible. An operator may use a manual compressor station valve at a continuously manned station as an alternative equivalent technology, and use of such valve would not require a notification to PHMSA in accordance with § 192.18 , but it must comply with § 192.636 .(h) The valve spacing requirements of paragraph (a) of this section do not apply to pipe replacements on a pipeline if the distance between each point on the pipeline and the nearest valve does not exceed:(1) Four (4) miles in Class 4 locations, with a total spacing between valves no greater than 8 miles;(2) Seven-and-a-half (71/2) miles in Class 3 locations, with a total spacing between valves no greater than 15 miles; or(3) Ten (10) miles in Class 1 or 2 locations, with a total spacing between valves no greater than 20 miles.35 FR 13257, Aug. 19, 1970, as amended by Amdt. 192-27, 41 FR 34606, Aug. 16, 1976; Amdt. 192-78, 61 FR 28784, June 6, 1996; Amdt. 192-85, 63 FR 37503, July 13, 1998; Amdt. 192-130, 87 FR 20982 , Apr. 8, 2022; Amdt. 192-134, 88 FR 50061 , Aug. 1, 2023 87 FR 20982 , 10/5/2022; Amdt. 192-134, 88 FR 50061 , 8/1/2023