A flange is a means of joining two conduits such as nozzles, pipelines, piping, tubing, etc. Weld neck flange thickness manual calculation It is usual to ensure that a flanged joint is stronger than the pipe or nozzle to which it is attached, i. Standard flanges are designed to remain pressure-tight even if yield stress is exceeded. Whilst these flanges are, in theory, interchangeable, each type is normally associated with a preferred application. For example: Welding Neck integral flanges are mostly used in pipelines and for the most demanding applications in terms of mechanical and hydrostatic loading.
A flange is a means of joining two conduits such as nozzles, pipelines, piping, tubing, etc. It is usual to ensure that a flanged joint is stronger than the pipe or nozzle to which it is attached, i. Standard flanges are designed to remain pressure-tight even if yield stress is exceeded. Whilst these flanges are, in theory, interchangeable, each type is normally associated with a preferred application.
For example: Welding Neck integral flanges are mostly used in pipelines and for the most demanding applications in terms of mechanical and hydrostatic loading. The socket design provides a smooth-bore through the joint significantly reducing erosion potential from multi-phase fluids. Slip-On loose flanges are for similar applications as the Socket design, except that they are more susceptible to erosion, corrosion, shock loading and vibration.
These flanges tend to be used in low-cost, low-demand applications. Lapped loose flanges are for applications where the flange and pipe are not to be welded together.
A stub-end is inserted in the flange and the stub-end is butt welded to the pipe. This facility is handy where the flange and pipe are manufactured from different materials. These flanges tend to be reserved for low pressure applications and those where external loads are negligible.
Swivel Ring flanges weld neck flange thickness manual calculation used for loose or integral flanges whose bolting ring must rotate to allow for stud-bolt alignment during assembly. Raised Faces are used for a number of reasons: 1 Easier gasket positioning and visibility 2 Facilitate high pressure RTJ gaskets 3 It is easier to install a leak detection facility Fig 2.
The standard thickness weld neck flange thickness manual calculation the raised face is 0. The raised face is not included in Flanges ' strength calculations. There are many different gasket designs for flanges but the two most popular are RTJ and 'Spiral Wound'. RTJ gaskets normally comprise soft iron or stainless steel and spiral wound gaskets usually comprise a stainless steel mesh with a suitable filler material.
RTJ gaskets are for high-pressure systems and come in a number of designs and materials but they all work similarly in that they seal on the corners of the ring section as opposed to flat gaskets, which seal on their faces.
When flanges are installed in areas where inspection is difficult e. A plunger manufactured from copper will ensure it remains free of marine growth. Flat gaskets are normally used for piping, as opposed to pipeline, systems where the loading conditions are less arduous than typical RTJ applications. Flat gaskets can comprise anything from polymer or vegetable fibre to soft metal iron, copper, aluminium, etc.
The most common flat gasket is the Spiral wound type. Refer to CalQlata's Flange Gaskets technical help page for more information on these items. Flange bolt loading for gasket seating pressure sealing and that required for external forces are not added together. Flange bolt loading will constitute the highest requirement, i. It is important to ensure that the gasket material is selected accordingly.
A flange is loaded in three ways: 1 Bolting load 2 Internal pressure 3 External forces and moments.Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action. Already a Member? Log In. It's easy to join and it's free. Register now while it's still free! Join your peers on the Internet's largest technical engineering professional community. Click Here to join Eng-Tips and talk with other members!
As the bolting load must be sufficient to restrain the internal pressure and the external forces and moments, the bolt load will always define the size and strength of the flange. Whilst API also provides a design specification sizing details for their pipeline flanges, it is similar to the ANSI design but does not provide a comprehensive calculation facility. Almost all design calculation codes and standards today tend to be based upon the ASME code. Where flanges are clad with a different material to its main body, e.
Inconel, Monel,Duplex, etc. The output data is complete according to Sub-Section 'Notation' of the design code to help you to verify the flange calculator's results. For this reason; where input and output data are for exactly the same property or dimension, their symbols may differ, e. The two unit systems accommodated in this calculator are metric mm and N and Imperial ins and lbf.
The ASME design code assumes you will be applying the allowable bolting stress during assembly. If this proves too arduous for your flange, you could increase its thickness treduce the allowable bolt stress or slightly reduce the bolt size. Conversely, if insufficient stresses are applied during installation, the flange could become loose over time due to material relaxation and ultimately leak.
Reducing the seating stress y and Gasket factor m see the flange gaskets technical help page also helps with reducing flange stresses.
By comparing ' W ' with the others, you will see which of them is causing the problem. All other dimensions and properties as listed below will remain unchanged as you switch between flange sizes. Bolting dimensions You can overwrite modify any database input value you wish and the calculation will be corrected incorporating your modified value. However, if you change the flange to a different size or type the modified value will be lost. Slip-On flange calculations can be used for Socket flanges greater than 3" as the calculations are identical and the Slip-On flange database includes sizes up to 48".
If this stress is too high, you simply increase the flange thickness t until it becomes acceptable. If your flange does not have a swivel ring, then ignore this result.
These calculations apply to the designs included in the calculator's database, and to any dimensional modifications you make to them. Flanges only applies to circular flanges of the types shown in Fig 1. However, care should be taken with allowable stresses for Lapped flanges in that they do not provide the same level of support as the Socket and Slip-On designs as the flange is not welded to the pipe.
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