Section 250.1002 - Design requirements for DOI pipelines(a) The internal design pressure for steel pipe shall be determined in accordance with the following formula: View Image
For limitations see section 841.121 of American National Standards Institute (ANSI) B31.8 (as incorporated by reference in § 250.198 ) where-
P = Internal design pressure in pounds per square inch (psi).
S = Specified minimum yield strength, in psi, stipulated in the specification under which the pipe was purchased from the manufacturer or determined in accordance with section 811.253(h) of ANSI B31.8.
D = Nominal outside diameter of pipe, in inches.
t = Nominal wall thickness, in inches.
F = Construction design factor of 0.72 for the submerged component and 0.60 for the riser component.
E = Longitudinal joint factor obtained from Table 841.1B of ANSI B31.8 (see also section 811.253(d) ).
T = Temperature derating factor obtained from Table 841.1C of ANSI B31.8.
(b)(1) Pipeline valves shall meet the minimum design requirements of ANSI/API Spec 6A (as incorporated by reference in § 250.198 ), ANSI/API Spec 6D (as incorporated by reference in § 250.198 ), or the equivalent. A valve may not be used under operating conditions that exceed the applicable pressure-temperature ratings contained in those standards.(2) Pipeline flanges and flange accessories shall meet the minimum design requirements of ANSI/ASME B16.5, ANSI/API Spec 6A, or the equivalent (as incorporated by reference in § 250.198 ). Each flange assembly must be able to withstand the maximum pressure at which the pipeline is to be operated and to maintain its physical and chemical properties at any temperature to which it is anticipated that it might be subjected in service.(3) Pipeline fittings shall have pressure-temperature ratings based on stresses for pipe of the same or equivalent material. The actual bursting strength of the fitting shall at least be equal to the computed bursting strength of the pipe.(4) If you are installing pipelines constructed of unbonded flexible pipe, you must design them according to the standards and procedures of ANSI/API Spec. 17J, as incorporated by reference in § 250.198 .(5) You must design pipeline risers for tension leg platforms and other floating platforms according to the design standards of API RP 2RD, Design of Risers for Floating Production Systems (FPSs) and Tension Leg Platforms (TLPs) (as incorporated by reference in § 250.198 ).(c) The maximum allowable operating pressure (MAOP) shall not exceed the least of the following: (1) Internal design pressure of the pipeline, valves, flanges, and fittings;(2) Eighty percent of the hydrostatic pressure test (HPT) pressure of the pipeline; or(3) If applicable, the MAOP of the receiving pipeline when the proposed pipeline and the receiving pipeline are connected at a subsea tie-in.(d) If the maximum source pressure (MSP) exceeds the pipeline's MAOP, you must install and maintain redundant safety devices meeting the requirements of section A9 of API RP 14C (as incorporated by reference in § 250.198 ). Pressure safety valves (PSV) may be used only after a determination by the Regional Supervisor that the pressure will be relieved in a safe and pollution-free manner. The setting level at which the primary and redundant safety equipment actuates shall not exceed the pipeline's MAOP.(e) Pipelines shall be provided with an external protective coating capable of minimizing underfilm corrosion and a cathodic protection system designed to mitigate corrosion for at least 20 years.(f) Pipelines shall be designed and maintained to mitigate any reasonably anticipated detrimental effects of water currents, storm or ice scouring, soft bottoms, mud slides, earthquakes, subfreezing temperatures, and other environmental factors. 76 FR 64462 , Oct. 18, 2011, as amended at 83 FR 49263 , Sept. 28, 2018