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Pipe Fitting Selection Guide

Pipe Fitting Selection Guide

AUTHOR : _ _ Date : 4/18/2013 11:35:56 PM

Pipe fittings are available in various shapes, sizes and materials. Used to connect pipes of different lengths 
and sizes, these
pipe fittings and flanges should make the right connections. Pipe and pipe-fittings are 
produced from a various materials for the transport of wide variety of solids and fluids. The wrong pipe 
fitting can lead to many problems like:

1. leaks
2. unwanted flow restrictions and
3. extra cost

The proper
pipe fittings and flanges let your equipment do the work that you intend it to do. The various 
types of pipe fittings include
plugs90 degree elbows, 45 degree elbowsflanges, nipples, concentric 
eccentric reducersstraight tees, reducing tees, unions, pipe caps, full coupling, half coupling 
and many more. You should select the right fittings for your application among the wide range of fitting 
types and sizes offered.

Common points to consider
The integrity of any fitting for proper functioning depends upon the following: 
1. Selection of correct components or fittings appropriate for the application
2. Careful preparation and cleaning
3. Careful installation and assembly
4. Correct tightening and loading

Selecting Your Pipe Fittings
The points to consider are as follows: 
1. Determine Material Compatibility: Material selection plays a vital role in the proper working of fittings. 
There are certain fluids which are not compatible with fitting material and these fittings cause leakage or 
system damage. It is very essential to check the material compatibility of your fluid with any chemicals.
2. Check Temperature and Pressure Conditions: Appropriate temperature and pressure ratings are 
needed for proper operating conditions. It is necessary to know whether the fittings are capable of 
performing at their maximum temperature and maximum pressure ratings because most fittings cannot 
perform both the task simultaneously.

Some popular fitting types
1. Threaded Pipe Fittings:
These are the most commonly used fittings based on certain standards. For instance, there are threaded fittings of pipes in BSP (British Standard Pipe), NPT (National Pipe Taper), UNF (Unified Fine Thread) sizes 
for permanent, high-pressure pipe connections.
Socket Weld Fittings:                                                                                                                                                                   
 A socket weld fitting is unthreaded, but has large sockets at both ends to accept a pipe end. The fitting is 
then permanently welded to the pipe.         
Butt Weld Fittings:
Buttweld (BW) fittings whose dimensions, dimensional tolerances et cetera are defined in the ASME B16.9 standards. Light-weight corrosion resistant fittings are made to MSS SP43.
flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system. It 
also provides easy access for cleaning, inspection or modification. 

• Pipe Thread Sizes
This is a very important consideration for any
pipe fitting. All pipes were manufactured with specification of a standardized outside diameter (OD) and wall thickness which in turn implies that the nominal pipe size is approximately equal to the inside diameter (ID). Nowadays, various thread configurations are used. We give below an example of British Standard Pipe (BSP) fittings for connecting systems that use both NPT and BSP thread configurations. The table shows a comparison of these two thread styles.


Threads per inch




1/8" 27 28
1/4" 18 19
3/8" 18 19
1/2" 14 14
3/4" 14 14

To sum up: Selection criteria for buyers 
1. Material
2. Pressure Ratings
3. Design and operation
4. Safety information
5. Temperature
pipe fittings and flanges, certain questions need to be answered for that particular pipe fitting and the manufacturer who is manufacturing that particular fitting. Some of these questions are as follows: 

Buyer's assistance
Before purchasing 
1. Can it handle pressure?
2. Can it handle high temperature?
3. Does it have proven long-term performance?
4. Are the joints or seals reliable?
5. Can it be fitted properly?
6. Does it have confidence of manufacturers?
7. Can it withstand outdoor storage and ultraviolet rays?
8. Can it resist punctures and abrasion?
9. Does it have widespread approval and acceptance from inspectors and engineers?
10. Does it have quality and value?The more the number of “YES”, the better is your product.

The more the number of “YES”, the better is your product.

• Check all kinds of pipe fittings
1. Elbow:
45 degree elbow
45D CS butt weld elbow    45D SS butt weld elbow   45D socket weld elbow   45D threaded elbow
90 degree elbow  
90D CS butt weld elbow    90D SS butt weld elbow   90D socket weld elbow
   90D threaded elbow     street elbow
180 degree elbow  
180D CS butt weld elbow      180D SS butt weld elbow

2. Tee:
CS butt weld straight tee   CS butt weld reducing tee   SS butt weld straight tee  SS butt weld reducing tee  socket weld tee   threaded tee
   Lateral tee:
CS butt weld lateral tee   SS butt weld lateral tee   socket weld lateral tee   threaded lateral tee

3. Cross:
CS butt weld straight cross   CS butt weld reducing cross   SS butt weld straight cross   SS butt weld reducing cross   socket weld cross   threaded cross

4. Reducer:
CS concentric reducer   CS eccentric reducer  SS concentric reducer   SS eccentric reducer

5. Cap:
CS butt weld cap   SS butt weld cap   socket weld cap   threaded cap

6. Stub end:
CS stub end   SS stub end

7. Coupling:
socket weld full coupling   socket weld half coupling   threaded full coupling   threaded half coupling

8. Union:
socket weld union   threaded union

9. Socket insert:
A  B

10. Plug:
hex head plug   square head plug   round head plug

11. Bushing:
hex head bushing   flush bushing 

12. Nipple: 
TBE   PBE   TOE&POE   hex nipple

13. Swaged nipple:
concentric swage nipple   eccentric swage nipple

14. Flange:
Orifice flange   lap joint flange   threaded flange   socket weld flange   weld neck flange   blind flange   slip on flange   long weld neck flange   plate flange   large diameter flange   spectacle blind   square flange   

15. Outolet:
weldolet   socketolet   threadolet  laterolet  coupolet  elolet   nipoflange   nipolet

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