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Piping Isometric Drawing-Purpose and necessary information

Isometrics are documents showing a three-dimensional Isometric view of Pipeline. One can say that it is the final outcome of all Piping Engineering activities. Once the Final Isometrics are released it is used at the site and/ or at fabricators for erection or fabrication. Separate Isometrics will be there for every other line. Isometrics are prepared in A3 Size sheets and shows the profile of a line but the dimensions are not to scale. Isometrics are made in different stages. The number of stages may vary from consultancy to consultancy. In the very first stage, detailed dimensions won’t be there except locating a valve or showing upstream/downstream straight lengths for flow nozzles etc. These sketches will send to Stress groups and interdepartmental check for their inputs. In the final stage after receiving comments from other departments, the Isos will update and include detailed dimensions, Support mark-up, Bill Of Material and release with the signature of Piping Lead, St...
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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 u...

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.         ...

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 stres...

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...