PIPING ENGINEERING TUTORIALS

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Piping Layout-Purpose and General Rules

A Refinery Even though it is one of the most important aspects of Piping Design, There is no established code exists for Piping Layout. Piping Layout is all about the arrangement of Piping. Layout Preparation doesn’t deal with the ability of the piping system to handle fluid under given design condition, rather deals with the efficient and safe operation of the plant. A talented Piping Layout Engineer should possess good craftsmanship with great personal skills, creative imaginations etc. In preparing a good Layout. Depending upon the particular situation, the piping arrangement will vary from case to case. To ensure a well laid out piping, a logical approach is necessary with an intelligent and careful study by the Piping Engineer.Piping Plans are usually made area wise. Piping Plans: A piping Plan is usually made in 1:33 1/3 scale for process units, 1:50 scale for pipe racks and validity units and 1:100 for Storage Tank Area. Generally, Piping Plans will be wit

Piping Specification-details and the preparation process

Piping Specifications are usually in the form of a manual containing the below-listed points, but not limited to 1 ) Pipe Class and Specifications. 2) Pipe and fittings thickness table for the different class of piping. 3) P & ID Abbreviations and Symbols. 4) List of fluids with Design conditions and Pipe Class. 5) List of Valves and Gaskets. 6) Table of Branch connections for different Pipe Classes. 7) Table of Bolt length. 8) Valve Dimensions. 9) Piping Scope Limit for instrumentation called as “Hook Up Diagram”. 10) Special Items list. Licensor transfers the basic piping specification as part of their basic engineering package, it generally includes a) List of mediums that have to handle with design conditions. b) Dimensional and material standard o

Details of Sustained and Displacement Stresses-Core of Pipe Stress Analysis

Piping flexibility analysis as per B31.3code requirements is dealing with two types of stress named as Sustained Stress and Displacement stress . Both types of stress must be considered separately because sustained stresses are associated with sustained forces while displacement stresses are associated with fixed displacements. SUSTAINED STRESSES: Sustained Stresses are stresses caused by loads that are not relieved as the piping system deflects. See the diagrammatic representation below to get an idea about this. The weight of the valve placed at the end of the cantilevered pipe induce Stress at the T-Joint. Regardless of the magnitude of the displacement (∆), the magnitude of the load (the weight of the valve) which causes the stress is unchanged. Therefore, to avoid catastrophic failure, the magnitude of any sustained stress must not exceed the yield strength of the material. Another example of a sustained stress is the hoop and longitudinal stresses induced by the

Wall Thickness Calculation of Pipes

Nominal Wall Thickness Calculation Of metallic pipes needs the following information as a Pre-requisite. a) Design Pressure, b) Design Temperature, c) Material Specification, d) Pipe Size e) Applicable Code As Per B 31.3, the required thickness of a Straight Section of Pipe is given by the relation t m =t+c Where , t m =Minimum thickness required including, mechanical corrosion and erosion allowance t=Thickness Required to withstand internal pressure c=Sum of Mechanical Allowance (thread, groove depth) added with corrosion and erosion allowance. Let's Go through each term in the above equation i) Thickness Required to withstand internal pressure [ t ] Nominal wall thickness should be Greater than or equal to the sum of the minimum required thickness and Manufacturer’s Negative tolerance. As per the Code Minimum Thickness t =PD/2(SE+PY) Here, P=Design Pressure (Gauge) D=Outside Diameter of Pipe S=Allowable Stress Value of