Home / Blog / Questions Related to Pipe Fittings:- Part-1

Questions Related to Pipe Fittings:- Part-1


1. How can flanges be classified based on pipe attachment?
Flanges can be classified based on pipe attachment as:-
Slip – on:- The Slip-on type flanges a re attached by welding inside as well as outside. These flanges are of forged construction.
Socket Weld:- The Socket Weld flanges are welded on one side only. These are used for small bore lines only.
Screwed:- The Screwed-on flanges are used on pipe lines where welding cannot be carried out.
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.
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.
Blind:- The Blind flanges are used to close the ends which need to be reopened.
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.
Integral:- Integral flanges are those, which ar e cast along with the piping component or equipment.
2. How can flanges be classified based on Pressure – temperature ratings?
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?
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?
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?
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?
A. Concentric or
B. Spiral (phonographic)
7. How the serration on flanges is specified?
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?
Concentric serration are insisted for face finish where the fluid being carried has very low density and can find leakage path through cavity.

9. How the gaskets are classified based on the type of construction?
Based on the type of construction, gaskets are classified as: –
A. Full face.
B. Spiral wound metallic.
C. Ring type.
D. Metal jacketed.
E. Inside bolt circle.
10. What is the most commonly used material for gasket?
Compressed Asbestos Fibre.
11. Which type of gasket is recommended for high temperature & high- pressure application?
Spiral Wound Metallic Gasket.
12. What are the criteria for selection of MOC of spiral wound metallic gasket winding material?
The selection of material of construction for gasket winding depends upon:-
A. The corrosive nature and concentration of fluid being carried.
B. The operating temperature of the fluid.
C. The relative cost of alternate winding material.
13. What are the most common materials used for spiral wound metallic gasket winding?
The most commonly used material for spiral wound metallic gasket winding is:-
A. Austenitic stainless steel 304 with asbestos filler.
B. Austenitic stainless steel 316 with asbestos filler.
C. Austenitic stainless steel 321 with asbestos filler.
14. Which material is used as filler material for spiral wound gasket in case of high temperature services?
For very high temperature services, graphite filler is used.
15. What is centering ring in connection to spiral wound gasket?
Spiral wound gaskets are provided with carbon steel external ring called centering ring.
16. What will be the AARH finish on flange face for using spiral wound gasket?
125-250 AARH finish.

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  1. Asbestos material is banned by most of the countries. So, answer for Qs. 10 is incorrect. Non-Asbestos is correct.

  2. Asbestos material is banned by most of the countries. So, answer for Qs. 10 is incorrect. Nos-Asbestos is correct.

  3. Tobias Armstrong

    I had no idea that there were so many tidbits of information related to pipes and fittings. So many of them seem to be of critical importance as well, so these questions and answers about things like flanges and gaskets seem like they’d be good to know the answers to. I’m trying to learn as much as I can about things like this, so I appreciate you sharing the answers. Thanks for sharing!

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