4.2.1 General 188.8.131.52 There is a commentary available for this Clause. The design pressure for each segment of the pipeline system shall
a) be specified by the designer;
b) be not less than the intended maximum operating pressure for that segment; and
c) include the pressure required to overcome static head, friction loss, and any required back pressure.
184.108.40.206 The effect of external pressures and loadings on the pipe during installation and operation shall be accounted for using good engineering practice. The pipe wall thickness selected shall provide adequate strength to prevent excessive deformation and collapse, taking into consideration mechanical properties, wall thickness tolerances, ovality, bending stresses, and external reactions (see Clauses 4.6 to 4.10). 220.127.116.11 Fluid expansion effects on pressure shall be considered for exposed piping and pressure-relieving devices shall be installed where required. 4.2.2 Temperature 18.104.22.168 There is a commentary available for this Clause. The design temperature range for each segment of the pipeline system shall be specified by the designer for the conditions expected during installation, pressure testing, start-up, and operation. Notes: 1) For carbon dioxide pipelines, extremely low temperatures can be encountered during pressure-relieving or pressure-reducing situations. 2) The environmental effects of pipeline operating temperatures, including any effect on plant growth and agricultural land use, should be considered. 22.214.171.124 The effects of thermal expansion and contraction shall be provided for in the design as specified in Clauses 4.6 to 4.10. 126.96.36.199 The temperature differential for restrained piping operating at a temperature higher than the installation temperature shall be limited to comply with the stress requirements for restrained portions of pipeline systems in Clause 4.7. The temperature differential shall be the difference between the maximum flowing fluid temperature and the metal temperature at the time of restraint.
188.8.131.52 For unrestrained piping, the thermal expansion temperature range to be used in the flexibility analysis in Clause 4.8 shall be the difference between the maximum and minimum operating temperatures. 184.108.40.206 For unrestrained piping, the temperature differential for the calculation of reactions shall be either the difference between the maximum operating temperature and the installation temperature or the difference between the minimum operating temperature and the installation temperature, whichever is greater. 4.2.3 Sustained force and wind loading The weight of pipe, components, contents, insulation cover, wind loading, and other sustained forces shall be considered in stress analysis for the various piping support circumstances encountered during pressure testing and operation (see Clauses 4.6 to 4.10). 4.2.4 Other loading and dynamic effects The stress design requirements in this Standard are specifically limited to design conditions for operating pressure, thermal expansion ranges, temperature differential, and sustained force and wind loadings. Additional loadings other than the specified operating loads are not specifically addressed in this Standard; however, the designer shall determine whether supplemental design criteria are necessary for such loadings and whether additional strength or protection against damage modes, or both, should be provided. Additional loadings not specifically addressed in this Standard include
a) occasional extreme loads, such as inertial earthquake;
b) slope movements;
c) fault movements;
d) seismic-related earth movements;
e) thaw settlement;
f) frost heave;
g) loss of support;
h) excessive overburden loads and cyclical traffic loads;
i) construction and maintenance deformations, including those resulting from horizontal directional
j) mechanical vibrations;
k) hydraulic shock; and
l) vortex shedding.