Calculation of safety valves in the detailed engineering design phase
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During the detailed engineering design phase, I saw that the safety calculations were indicated in the foundation engineering design documents as being done during this phase; why couldn’t they be calculated in the previous phase? Is it reasonable to request the “leakage amount”? Because I can’t do the calculation here, I guess. .
Are you calculating the safety valve for a pipeline? Or the calculation of the safety valve on the equipment? Generally, the calculation and selection of safety valves are carried out during the detailed design phase; such detailed considerations are not taken into account in the preliminary design.
In accordance with Article 3.1 of SHSG-033-2008 \"Requirements for the Design Content of Foundation Engineering for Petrochemical Plants\", the design documents for the foundation part of the process system shall include the basis for process design, process descriptions, boundary condition tables, pipe lists, process equipment lists, PFDs, utility flow diagrams (UFDs), PID diagrams, data sheets for process equipment, as well as data sheets or specifications for safety valves and burst discs, along with summary tables. During the basic design process, the safety valve data sheet should include information on operating and selection conditions, model selection, materials, and accessories. In the past, when we carried out the preliminary design, we would calculate the discharge capacity of the safety valves. According to clause 2.2.5.2 of SHSG-053-2011 \"Regulations on the Content of Detailed Engineering Design for Petroleum and Petrochemical Plants\", it is necessary at this stage to determine the diameters of the inlet and outlet pipes of the safety valve, as well as the dimensions of its throat.
During the basic design phase, detailed parameters for equipment and control valves are not available; therefore, the discharge capacity of the safety valve must be determined during the detailed design phase. This is why this sentence was added in the notes of the safety valve data sheet.
The safety valve data sheet has been provided during the foundation engineering design phase.
In my understanding, although there are relevant guidelines that specify the requirements for the depth of detailed design and preliminary design, it still depends on the depth of the preliminary design for your project as well as the requirements for design documentation. If the detailed design does not require reevaluation of operating conditions or the type/size of equipment, and if the preliminary design stage is already quite thorough (usually thanks to a dedicated process package or a sufficient time frame for design work), then the preliminary design should include a comprehensive table of selected process parameters ensuring safety. In such cases, the detailed design simply involves converting those parameters into procurement documents in order to proceed with specific quotations and purchases. If that’s not the case, then the detailed design becomes a rather tedious task of making up for deficiencies~~~
Procedurally, a data sheet for safety valves should be available during the basic engineering design phase. Good suppliers are available already at the process package stage.