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STP-PT-048-2013 pdf free

The Appendix in its entirety is explicitly applicable to onshore pipeclines transporting non-sour lean natural gas. This statement is not intended to convey that any of the content is inapplicable to other types of pipeclines, but rather that there are certain aspects of the document that are specific to non-sour Ican
natural gas pipelines. Specifically, “the reliability targets in Section R1.6 are based on a model that evaluates the consequences of an ignited lean natural gas release at pressures consistent with the assumption of ideal gas behaviour.” These targets should therefore not be used directly for other gas compositions or ultra-high pressures that may have significantly different rclease conscquences than those of lean natural gas. For rich gas (depending on the particular composition), it may be possible to demonstrate that the underlying rclease conscquence model just mentioned is applicable, and in such cases, the targets can be applied directly. If the model docs not apply directly, the Appendix may be used with casc-specific reliability targets that meet the risk criteria underlying the Appendix. Such targets can be devcloped by adjusting the targets in the Appendix based on the relative magnitude of the release consequences associated with the rich gas composition and/or ultra-high pressure (as calculated from a suitable model) and those calculated from the model underlying the Appendix for the same pipecline. Details of this process can be inferred from the original methodology used in developing the reliability
targets in the Appendix (Nessim et al.) [],[2]. It may also be possible to extend applicability of the Appendix to other fluids, such as sour gas, by making similar adjustments to the reliability targets, as long as the relcase conscquenccs associated with thesc fluids are dominated by human safety considerations.Apart from the reliability targets and the spccific procedure uscd in demonstrating compliance with them, much of the content of the Appendix is applicable to a wide varicty of pipclines. This includes all requirements and other information related to the calculation of reliability with respect to different integrity threats.
Users are advised “to consult the Commentary and the reference material that support the provisions of this Appendix to ensure that the parameters to be used in the design are within the range of applicability of the consequence models used for reliability target calibration.” The targets were devcloped based on a safety benchmark that was calculated from a set of pipeline designs represented by different combinations of diameter, pressure, grade and class location (Nessim et al.) [1], [2]. As required by the calibration approach, these cascs were sclected to cover the rangc of pipcline paramcters that existed at the time of target devclopment. The calculation involved usc of a spccific consequence model, which is built into the targets. The intent is to state that if use of the Appendix is considered for pipelines that have design parameters outside the range of the test cascs used in the calibration, a check must be carried out to ensure that the consequence model used in the calibration can be reasonably applied to thesc pipelincs. The intent is not to imposc a limitation on the application of the targets for pipelines that are outside the range defined by the test cases, as long as the consequence model is shown to apply. For example, the test cases used in target calibration covered a pressure range of 600 to 1400 psig (4.16 to 9.66 MPa). To apply the targets to a pipeline that has an intemal pressure of 1500 psig (1035 MPa), the user should ensure that the rclease consequence model is applicable to a pipeline opcrating at 1500 psig (10.35 MPa). If this is the casc, then the targets can be uscd for the pipeline even though the pressure is outside the range of pressures considered in the test cascs used in the target calibration.STP-PT-048 pdf free download.

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