3 December 2022

Flanges | Pipe Flanges | Classification of Flanges

Flanges

1. How can flanges be classified based on Pipe Attachment?

Answer: –

Flanges can be classified based on pipe attachment as: –

1.) Slip – on:- The Slip-on type flanges are attached by welding inside as well as outside. These flanges are of forged construction.

2.) Socket Weld: – The Socket Weld flanges are welded on one side only. These are used for small bore lines only.

3.) Screwed: – The Screwed-on flanges are used on pipe lines where welding cannot be carried out.

4.) Lap Joint: – The Lap Joint flanges are used with stub ends. The stub ends are welded with pipes & flanges are kept loose over the same.

5.) Welding Neck: – The Welding neck flanges are attached by butt welding to the pipe. These are used mainly for critical services where the weld joints need radiographic inspection.

6.) Blind: – The Blind flanges are used to close the ends which need to be reopened.7.) Reducing. : – The reducing flanges are used to connect between larger and smaller sizes without using a reducer. In case of reducing flanges, the thickness of flange should be that of the higher diameter.

7.) Integral: – Integral flanges are those, which are cast along with the piping component or equipment.

2. How can flanges be classified based on Pressure- temperature ratings?

Answer: –

Flanges are classified based on pressure temperature ratings as: –
A. 150
B. 300
C. 400
D. 600
E. 900
F. 1500
G. 2500

Pressure temperature rating carts in the standard ASME16.5 specify the non-shock working gauge pressure to which the flange can be subjected to at a particular temperature.

3. How can flanges be classified based on facing?

Answer: –
Flanges are classified based on facing as: –
A. Flat face. (FF)
B. Raised face. (R/F)
C. Tongue and groove. (T/G)
D. Male and female. (M/F)
E. Ring type joint. (RTJ)

4. How can flanges be classified based on face finish?

Answer: –
Flanges are classified based on face finish as: –
A. Smooth finish.
B. Serrated finish.

5. Where the smooth finish flange & serrated finish flange finds its use?

Answer: –
The smooth finish flange is provided when metallic gasket is provided and serrated finish flange is provided when non-metallic gasket is provided.

6. What are the types of serrated finish provided on flange face?

Answer: –
A. Concentric or
B. Spiral (Phonographic)

7. How the serration on flanges is specified?

Answer:
The serration on flanges is specified by the number, which is the Arithmetic Average Rough Height (AARH).

8. Where the concentric serration is insisted for face finish?

Answer: –
Concentric serration are insisted for face finish where the fluid being carried has very low density and can find leakage path through cavity.

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