Part 255 Transmission and Distribution of Gas

The following definitions apply to a GDPIM plan: (a) Excavation damage means any impact that results in the need to repair or replace an underground facility due to a weakening, or the partial or complete destruction, of the facility, including, but not limited to, the protective…

(a) Unless exempted in subdivision (b) of this section, sections 255.1003 through 255.1015 of this Part prescribe the minimum requirements for a GDPIM program for any gas distribution pipeline covered under this Part, including liquefied petroleum gas systems. A gas distribution …

No later than August 2, 2011 a gas distribution operator must develop and implement an GDPIM program that includes a written GDPIM plan as specified in section 255.1007 of this Part.

A written GDPIM plan must contain procedures for developing and implementing the following elements: An operator must demonstrate an understanding of its gas distribution system developed from reasonably available information. (1) Identification of the characteristics of the pipe…

(a) Except as provided in subdivision (b) of this section, each operator of a distribution pipeline system must submit a report on each mechanical fitting failure, excluding any failure that results only in a nonhazardous leak, on a Department of Transportation form PHMSA F-7100.…

Sections 255.103 through 255.125 of this Part prescribe the minimum requirements for the design of pipe.

An operator must maintain records demonstrating compliance with the requirements of sections 255.1003 through 255.1015 of this Part for at least 10 years. The records must include copies of superseded GDPIM plans developed under sections 255.1003 through 255.1015 of this Part.

(a) An operator may propose to reduce the frequency of periodic inspections and tests required in this Part on the basis of the engineering analysis and risk assessment required by sections 255.1003 through 255.1015 of this Part. (b) An operator must submit its proposal to the Pu…

No later than August 2, 2011 the operator of a master meter or small LPG system must develop and implement a GDPIM program that includes a written GDPIM plan as specified in subdivision (b) of this section. The GDPIM program for these pipelines should reflect the relative simplic…

Pipe must be designed with sufficient wall thickness, or must be installed with adequate protection to withstand anticipated external pressures and loads that will be imposed on the pipe after installation.

(a) The design pressure for steel pipe is determined in accordance with the following formula: P = (2 St/D) × F × E × T P = Design pressure in pounds per square inch (kPa) gauge. S = Yield strength in pounds per square inch (kPa) determined in accordance with section 255.107 of t…

(a) For pipe that is manufactured in accordance with a specification listed in section I of Appendix 14-B of this Title, the yield strength to be used in the design formula in section 255.105 of this Part is the SMYS stated in the listed specification, if that value is known. (b)…

(a) If the nominal wall thickness for steel pipe is not known, it is determined by measuring the thickness of each piece of pipe at quarter points on one end. (b) However, if the pipe is of uniform grade, size, and thickness and there are more than 10 lengths, only 10 percent of …

(a) Each plant that supplies petroleum gas by pipeline to a natural gas distribution system must meet the requirements of this Part and NFPA 58 and NFPA 59 (as described in section 10.3 of this Title). (b) Each pipeline system subject to this Part that transports only petroleum g…

(a) Except as otherwise provided in subdivisions (b), (c) and (d) of this section, the design factor to be used in the design formula in section 255.105 of this Part is determined in accordance with the following table: (b) A design factor of 0.60 or less must be used in the desi…

(a) The longitudinal joint factor to be used in the design formula in section 255.105 of this Part is determined in accordance with the following table: As described in section 10.3 of this Title. (b) If the type of longitudinal joint cannot be determined, the joint factor to be …

(a) The temperature derating factor to be used in the design formula in section 255.105 is determined as follows: (b) For intermediate gas temperatures, the derating factor is determined by interpolation.

(a) Design formula. Design formulas for plastic pipe are determined in accordance with either of the following formulas: P = 2StDF/(D − t) P = 2SDF/(SDR − 1) Where: P = Design pressure, gauge, psig (kPa). S = For thermoplastic pipe, the hydrostatic design basis (HDB) is determine…

(a) Copper pipe used in mains must have a minimum wall thickness of 0.065 inch (1.65 millimeters) and must be hard drawn. (b) Copper pipe used in service lines must have a minimum wall thickness as specified for type “L” pipe in ASTM B 88. (c) Copper pipe used in mains and servic…

(a) The rules and regulations of this Part are considered adequate for safety under conditions normally encountered in the gas industry. However, these rules and regulations cannot specifically provide for all abnormal or unusual conditions; nor can they specifically detail all m…

(a) A steel pipeline previously used in other than natural gas service qualifies for use under this Part if the operator prepares and follows a written procedure to carry out the following requirements: (1) The design, construction, operating, and maintenance history of the pipel…

Sections 255.143 through 255.193 of this Part prescribe the minimum requirements for the design and installation of pipeline components and facilities, other than overpressure protection.

(a) Each component of a pipeline must be able to withstand operating pressures and other anticipated loadings without impairment of its service ability with unit stresses equivalent to those allowed for comparable material in pipe in the same location and kind of service. However…

Notwithstanding any requirement of this Part which incorporates by reference an edition of a document listed in section 10.3 or Appendix 14-B of this Title, a metallic component manufactured in accordance with any other edition of that document is qualified for use under this Par…

(a) Except for cast iron and plastic valves, each valve must meet the minimum requirements, or the equivalent, of ANSI/API 6D (as described in section 10.3 of this Title). A valve may not be used under operating conditions that exceed the applicable pressure-temperature ratings c…

(a) Each flange or flange accessory must meet the minimum requirements of ASME/ANSI B16.5 or MSS SP-44 (as described in section 10.3 of this Title), or the equivalent. (b) Each flange assembly must be able to withstand the maximum pressure at which the pipeline is to be operated …

(a) The minimum metal thickness of threaded fittings may not be less than specified for the pressures and temperatures in the applicable standards referenced in this Part, or their equivalent. (b) Each steel butt-welding fitting must have pressure and temperature ratings based on…

(a) As used in this Part: (1) includes means including but not limited to; (2) may means is permitted to or is authorized to; (3) may not means is not permitted to or is not authorized to; and (4) shall is used in the mandatory and imperative sense. (b) In this Part: (1) words in…

(a) Except as provided in subdivision (b) of this section, each new transmission line and each pipe section, valve, fitting or other line component of a transmission line that is replaced must be designed and constructed to accommodate the passage of instrumented internal inspect…

(a) Each mechanical fitting used to make a hot tap must be designed for at least the operating pressure of the pipeline. (b) Where a ductile iron pipe is tapped, the extent of full-thread engagement and the need for the use of outside-sealing service connections, tapping saddles,…

(a) Except for branch connections and assemblies of standard pipe and fittings joined by circumferential welds, the design pressure of each component fabricated by welding, whose strength cannot be determined, must be established in accordance with paragraph UG-101 of the ASME Bo…

(a) Each welded branch connection made to pipe in the form of a single connection, or in a header or manifold as a series of connections, must be designed to ensure that the strength of the pipeline system is not reduced, taking into account the stresses in the remaining pipe wal…

Each extruded outlet must be suitable for anticipated service conditions and must be at least equal to the design and strength of the pipe and other fittings in the pipeline to which it is attached.

Each pipeline must be designed with enough flexibility to prevent thermal expansion or contraction from causing excessive stresses in the pipe or components, excessive bending or unusual loads at joints, or undesirable forces or moments at points of connection to equipment, or at…

(a) Each pipeline and its associated equipment must have enough anchorage or support to: (1) prevent undesigned-for strain on connected equipment; (2) resist longitudinal forces caused by a bend or offset in the pipe; and (3) prevent or damp out excessive vibration. (b) Each expo…

(a) Each main compressor building of a compressor station must be located on property under the control of the operator. It must be far enough away from adjacent property, not under control of the operator, to minimize the possibility of catching on fire from a conflagration at s…

(a) Where entrained vapors in gas may liquefy under the anticipated pressure and temperature conditions, the compressor must be protected against the introduction of those liquids in quantities that could cause damage. (b) Each liquid separator used to remove entrained liquids at…

Except for unattended field compressor stations of 1,000 horsepower (746 kilowatts) or less, each compressor station must have an emergency shutdown system that meets the following: (a) It must be able to block gas out of the station and blow down the station piping. (b) It must …

(a) Each compressor station must have pressure relief or other suitable protective devices of sufficient capacity and sensitivity to ensure that the maximum allowable operating pressure of the station piping and equipment is not exceeded by more than 10 percent. (b) Each vent lin…

(a) Notwithstanding the requirements of Part 293 or 733 of this Title, the minimum period of retention of records required by this Part shall be at least three years. Longer periods of retention may be mandated by section 255.517 of this Part, Parts 293 and 733 of this Title. Lon…

(a) Each compressor station must have adequate fire protection facilities. If fire pumps are a part of these facilities, their operation may not be affected by the emergency shutdown system. (b) Each compressor station prime mover, other than an electrical induction or synchronou…

Each compressor station building must be ventilated to ensure that employees are not endangered by the accumulation of gas in rooms, sumps, attics, pits, or other enclosed places.

(a) Each pipeline to operate at 125 psig (862 kPa) or more must have sectionalizing block valves spaced according to the following: (1) Each point on the pipeline in a Class 4 location must be within ½ mile (0.805 kilometer) of a valve. (2) Each point on the pipeline in a Class 3…