Uprating: Steel Pipelines to a Pressure That Will Produce a Hoop Stress Less Than 30 Percent of SMYS: Plastic, Cast Iron, and Ductile Iron Pipelines [49 CFR 192.557]

Snapshot 2026-08-12 Government source

Louisiana Office of ConservationOfficial agency material

A. Unless the requirements of this Section have been met, no person may subject: [49 CFR 192.557(a)]

1. a segment of steel pipeline to an operating pressure that will produce a hoop stress less than 30 percent of SMYS and that is above the previously established maximum allowable operating pressure; or [49 CFR 192.557(a)(1)]

2. a plastic, cast iron, or ductile iron pipeline segment to an operating pressure that is above the previously established maximum allowable operating pressure. [49 CFR 192.557(a)(2)]

B. Before increasing operating pressure above the previously established maximum allowable operating pressure, the operator shall: [49 CFR 192.557(b)]

1. review the design, operating, and maintenance history of the segment of pipeline; [49 CFR 192.557(b)(1)]

2. make a leakage survey (if it has been more than one year since the last survey) and repair any leaks that are found, except that a leak determined not to be potentially hazardous need not be repaired, if it is monitored during the pressure increase and it does not become potentially hazardous; [49 CFR 192.557(b)(2)]

3. make any repairs, replacements, or alterations in the segment of pipeline that are necessary for safe operation at the increased pressure; [49 CFR 192.557(b)(3)]

4. reinforce or anchor offsets, bends and dead ends in pipe joined by compression couplings or bell and spigot joints to prevent failure of the pipe joint, if the offset, bend, or dead end is exposed in an excavation; [49 CFR 192.557(b)(4)]

5. isolate the segment of pipeline in which the pressure is to be increased from any adjacent segment that will continue to be operated at a lower pressure; and [49 CFR 192.557(b)(5)]

6. if the pressure in mains or service lines, or both, is to be higher than the pressure delivered to the customer, install a service regulator on each service line and test each regulator to determine that it is functioning. Pressure may be increased as necessary to test each regulator, after a regulator has been installed on each pipeline subject to the increased pressure. [49 CFR 192.557(b)(6)]

C. After complying with Subsection B of this Section, the increase in maximum allowable operating pressure must be made in increments that are equal to 10 psi (69 kPa) gage or 25 percent of the total pressure increase, whichever produces the fewer number of increments. Whenever the requirements of Paragraph B.6 of this Section apply, there must be at least two approximately equal incremental increases. [49 CFR 192.557(c)]

D. If records for cast iron or ductile iron pipeline facilities are not complete enough to determine stresses produced by internal pressure, trench loading, rolling loads, beam stresses, and other bending loads, in evaluating the level of safety of the pipeline when operating at the proposed increased pressure, the following procedures must be followed. [49 CFR 192.557(d)]

1. In estimating the stresses, if the original laying conditions cannot be ascertained, the operator shall assume that cast iron pipe was supported on blocks with tamped backfill and that ductile iron pipe was laid without blocks with tamped backfill. [49 CFR 192.557(d)(1)]

2. Unless the actual maximum cover depth is known, the operator shall measure the actual cover in at least three places where the cover is most likely to be greatest and shall use the greatest cover measured. [49 CFR 192.557(d)(2)]

3. Unless the actual nominal wall thickness is known, the operator shall determine the wall thickness by cutting and measuring coupons from at least three separate pipe lengths. The coupons must be cut from pipe lengths in areas where the cover depth is most likely to be the greatest. The average of all measurements taken must be increased by the allowance indicated in the following table. [49 CFR 192.557(d)(3)]

Allowance (inches)(millimeters)

Cast Iron Pipe

Pipe Size (inches)(millimeters)

Pit Cast Pipe

Centrifugally Cast Pipe

Ductile Iron Pipe

3 to 8 (76 to 203)

0. 075 (1.91)

0. 065 (1.65)

10 to 12 (254 to 305)

0. 08 (2.03)

0. 07 (1.78)

14 to 24 (356 to 610)

0. 08 (2.03)

0. 075 (1.91)

30 to 42 (762 to 1067)

0. 09 (2.29)

0. 075 (1.91)

48 (1219)

0. 09 (2.29)

0. 08 (2.03)

54 to 60 (1372 to 1524)

0. 09 (2.29)

4. For cast iron pipe, unless the pipe manufacturing process is known, the operator shall assume that the pipe is pit cast pipe with a bursting tensile strength of 11,000 psi (76 Mpa) gage and a modulus of rupture of 31,000 psi (214 Mpa) gage. [49 CFR 192.557(d)(4)]

AUTHORITY NOTE: Promulgated in accordance with R.S. 30:501 et seq.

HISTORICAL NOTE: Promulgated by the Department of Natural Resources, Office of Conservation, LR 9:239 (April 1983), amended LR 10:531 (July 1984), LR 18:857 (August 1992), LR 27:1546 (September 2001), LR 30:1259 (June 2004).