Are you confused about choosing the right flanges for your piping network? Or, Are you having trouble with the already fitted flanges but you don’t understand where you went wrong with your choice of flanges? Then this blog is all you need, so you can understand critically each aspect related to it.
Piping
A pipe is a cylindrical object used to propagate fluids, gases etc. Piping is needed everywhere ranging from primary areas to secondary areas. Piping is designed, built, and maintained righteously by engineers by keeping in view each element used for it’s detailing. There is a wide range of variety in pipes such as Polypropylene pipes, Stainless Steel pipes, Plastic pipe, Concrete pipe, Chlorinated Poly Vinyl Chloride Pipes(CPVC) etc. These pipes are used according to their needs in the respective places and they all have their own distinctive functions to perform. Pipes are used in household areas, large buildings, factories, oil and gas areas etc. With pipes also comes maintenance and care so that they can last for a long time and the pipe networking runs smoothly without any issue.
Flanges and its types
Let us first get well versed with the flanges and then we will learn about its types and uses.
Flanges can be understood by comparing it with welding. Welding is a method which is used to join two parts of pipe permanently whereas flanges is also used to join two parts of pipe but on a temporary basis. Flange is the second most widely used joining method after welding. It is used where joints need dismantling. It provides flexibility for maintenance.It is of utmost importance when it comes to maintaining pipes as in place of valves, flange is used as a substitute in order to hold that position up for time being. It is basically a mechanical joint. Each kind of flange has its own special quality and it should be selected carefully to meet the specific requirement.
There are three integral parts of the flange joint – Flange, Gasket and Bolting. When we join two flanges together, a gasket is needed which prevents leakage, or we can say it acts as a seal. Then, there are fasteners used as stud bolts in flange circles.
Types of Flanges used in piping application:
- Weld-Neck Flange
This type of flange is most widely used in process piping.It is suitable for the areas where the temperatures and pressures are very high. It is costly in comparison to other flanges and is bulky in size. It has a neck like structure and is attached using butt welding that is why it is known as weld-neck flange.
- Slip-on Flange
It is also widely used in the industry; the pipe is moved into the flange and then is fitted with the help of fillet welding on both sides. It is highly recommended for low temperatures and pressures. It is in a circular shape and its diameter is slightly bigger than the diameter of the pipe.
- Threaded Flange
This type of flange contains thread on the inner side of the bore which is used to tighten the pipe. It is also used mostly in low temperature and low pressure and not suitable for the high pressures or temperature application. Threaded flange is also called a screwed flange because it looks alike. These are used mostly in utility systems, i.e, airlines, waterlines etc. It is a speedy connection and does not require much time. It does not work well with the pipe with less wall thickness.
- Socket- weld Flange
This type contains a socket inside which is also known as female socket and the pipe is slid into it, then it is joined with the help of fillet welding from one side along the pipe. Socket-weld flange is also suitable for low pressures and temperatures. It is the same as that of threaded flange but in place of threads there are sockets inside the bore
- Lap Joint Flange
This kind of flange consists of two parts. The first part of this one is called Stub End and the other part is known as Backing flange. One end of Stub End is butt welded with the pipe. And the backing flange which is connected with the other flange. This is used in those areas where frequent dismantling is required.
- Blind Flange
It is like a bank disc which is used at the end of the pipe or is used to isolate the line or terminate the flow. It can also be used as a substitute for a valve to close the line when a valve is removed for repairing or other issues.
Classification of Flange on the basis of their Faces
- Flat-Face Flange (FF)
It is called a flat face flange because the face of this flange is flat. These are suitable for low pressure areas and they do not go well with raised face flanges.
- Raised Face Flange (RF)
The part around the face of the flange remains slightly raised in this one. They go well with pressure ranging from 150 to 300.
- Male and female face (M&F)
These two flanges are always used together. The only difference between the two is that the face of male flange remains slightly raised while the female flange has a groove in it. These kinds of flanges are used in heat exchange areas.
- Tongue and Groove flange (T&G)
They are also used together in a set. It does not corrode off which makes it suitable for areas like chemical industries, oil and petroleum sector etc. They are best suited for high pressure areas.
- Ring Type Joint (RT
This kind of flange has a ring type finishing in it. They are suitable for high temperatures and high pressures. It has a class #600 or higher.
Flange Classes
#150
#300
#600
#900
#1500
#2500
Standardisation of Flanges
There are multiple standards that ensure the quality of manufacturers and sellers and these are to be considered when buying flanges. Manufacturer requires these standards to reflect the best quality and certainty of the certifications.
- ISO 9001 AND ISO 14001
- JIS B2220
- En 1092, BS 3293, etc.
