What are pipe fittings

What are pipe fittings?

Pipe fittings are general terms for components in the piping systems that function as connection, control, direction change, split, seal, and support.

According to different processing methods, it is divided into four categories, namely butt welding pipe fittings (both weld and no weld), socket welding and threaded pipe fittings, flanged pipe fittings. 
Common classification of

There are many types of pipe fittings, which are classified according to the use, connection, materials, and processing methods.

By purpose By connection
Socket weld pipe fittings Buttweld pipe fittings
Threaded pipe fittings Outlet pipe fittings
By material Standards of pipe fittings
Applications and markets of pipe fittings How to get high quality pipe fittings

By purpose

  • Pipe fittings for connecting pipes are: flange, union, expansion joint, coupling, ferrule, hose clamp, swage nipple, etc.
  • Change the pipe direction of the pipe: elbow, bend, pipe tee, pipe cross, adapters, olet (weldolet, sockolet, elbowlet, thredolet, nipolet, letrolet, swepolet)
  • Pipe fittings that change the pipe diameter: reducer, branch pipe
  • Pipe fittings for pipeline sealing: gasket, pipe plug, blind flange, head, cap
  • Pipe fittings for pipe fixing: snap ring , tow hook, lifting ring, bracket, bracket, pipe card, etc.

By connection

  • Buttweld pipe fittings
  • Threaded pipe fittings
  • Socket weld pipe fittings
  • Outlet Pipe Fittings

Socket weld pipe fittings

Socket weld pipe fittings - What are pipe fittings

A Socket Weld is a pipe attachment detail in which a pipe is inserted into a recessed area of a Valve, fitting or flange. In contrast to buttweld pipe fittings, Socket Weld fittings are mainly used for small pipe diameters (Small Bore Piping); generally for piping whose nominal diameter is NPS 2 or smaller.

To join pipe to Valves and fittings or to other sections of pipe, fillet-type seal welds be used. Socket Welded Joints construction is a good choice wherever the benefits of high leakage integrity and great structural strength are important design considerations.

Fatigue resistance is lower than that in butt-welded construction due to the use of fillet welds and abrupt fitting geometry, but it is still better than that of most mechanical joining methods.

Some details of socket weld pipe fittings

SW Fittings are family of high pressure fittings are used in various industrial processes.

  • They are used for lines conveying flammable, toxic or expensive material where no leakage can be permitted, and for steam 300 to 600 PSI.
  • They are used only in conjunction with ASME Pipe and are available in the same size range.
  • They are used in areas where pipe-work is permanent and are designed to provide good flow characteristics.
  • They are are produced to several ASTM standards and are manufactured in accordance with ASME B16.11. The B16.11 standard covers pressure-temperature ratings, dimensions, tolerances, marking, and material requirements for forged carbon and alloy steel. Acceptable material forms are forgings, bars, seamless pipe, and seamless tubes which conform to the fittings chemical requirements, melting practices, and mechanical property requirements of ASTM A105, A182, or A350.
  • They are available in three pressure ratings: Class 3000, 6000 and 9000.

Advantages and disadvantages of socket weld fittings

Advantages

  • The pipe need not be beveled for weld preparation.
  • Temporary tack welding is no needed for alignment, because in principle the fitting ensures proper alignment.
  • The weld metal can not penetrate into the bore of the pipe.
  • They can be used in place of threaded fittings, so the risk of leakage is much smaller.
  • Radiography is not practical on the fillet weld; therefore correct fitting and welding is crucial. The fillet weld may be inspected by surface examination, magnetic particle (MP), or liquid penetrant (PT) examination methods.
  • Construction costs are lower than with butt-welded joints due to the lack of exacting fit-up requirements and elimination of special machining for butt weld end preparation.

Disadvantages

The welder should ensure for a expansion gap of 1/16 inch (1.6 mm) between de pipe and the shoulder of the socket.
ASME B31.1 para. 127.3 Preparation for Welding (E) Socket Weld Assembly says:

  • In assembly of the joint before welding, the pipe or tube shall be inserted into the socket to the maximum depth and then withdrawn approximately 1/16″ (1.6 mm) away from contact between the end of the pipe and the shoulder of the socket.
  • The expansion gap and internal crevices left in socket welded systems promotes corrosion and make them less suitable for corrosive or radioactive applications where solids buildup at the joints may cause operating or maintenance problems. Generally require butt welds in all pipe sizes with complete weld penetration to the inside of the piping.
  • Socket welding are unacceptable for UltraHigh Hydrostatic Pressure (UHP) in Food Industry application since they do not permit full penetration and leave overlaps and crevices that are very difficult to clean, creating virtual leaks.

The purpose for the bottoming clearance in a Socket Weld is usually to reduce the residual stress at the root of the weld that could occur during solidification of the weld metal, and to allow for differential expansion of the mating elements.

Buttweld pipe fittings

Buttweld pipe fittings - What are pipe fittings

A pipe fitting is defined as a part used in a piping system, for changing direction, branching or for change of pipe diameter, and which is mechanically joined to the system. There are many different types of fittings and they are the same in all sizes and schedules as the pipe.

Fittings are divided into three groups:

  • Buttweld (BW) pipe 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.
  • Socket Weld (SW) pipe fittings Class 3000, 6000, 9000 are defined in the ASME B16.11 standards.
  • Threaded (THD), screwed fittings Class 2000, 3000, 6000 are defined in the ASME B16.11 standards.

Applications of buttweld pipe fittings

A piping system using buttweld pipe fittings has many inherent advantages over other forms.

  • Welding a fitting to the pipe means it is permanently leakproof.
  • The continuous metal structure formed between pipe and fitting adds strength to the system.
  • Smooth inner surface and gradual directional changes reduce pressure losses and turbulence and minimize the action of corrosion and erosion
  • A welded system utilizes a minimum of space.

Bevelled ends

The ends of all buttweld pipe fittings are bevelled, exceeding wall thickness 4 mm for austenitic stainless steel, or 5 mm for ferritic stainless steel. The shape of the bevel depending upon the actual wall thickness. This bevelled ends are needed to be able to make a “Butt weld”.

ASME B16.25 covers the preparation of buttwelding ends of piping components to be joined into a piping system by welding. It includes requirements for welding bevels, for external and internal shaping of heavy-wall components, and for preparation of internal ends (including dimensions and dimensional tolerances). These weld edge preparation requirements are also incorporated into the ASME standards (e.g., B16.9, B16.5, B16.34).

Material and performance

  • The most common materials used in fittings produced is carbon steel, stainless steel, cast iron, aluminium, copper, glass, rubber, the various types of plastics, etc..
  • In addition, fittings, like pipes, for specific purposes sometimes internally equipped with layers of materials of a completely different quality as the fitting themselves, which are “lined fittings”.
  • The material of a fitting is basically set during the choice of the pipe, in most cases, a fitting is of the same material as the pipe.

What is a seamless buttweld pipe fitting?

  • A seamless butt weld pipe fitting is made directly from a section of seamless pipe material, by applying heat and pressure to transform pipe directly into an elbow or other shape.
  • A seamless fitting has no welded parts by itself, a characteristic demanded in some critical applications.
  • By comparison, a regular butt weld fitting has one, two or more welds, depending on dimension, shape and manufacturing method.
  • No weld means less risk of weld yield and porosities.

Threaded pipe fittings

Threaded pipe fittings - What are pipe fittings

Threaded joints probably represent the oldest method of joining piping systems. Like Socket Weld fittings, threaded fittings are mainly used for small pipe diameters (Small Bore Piping); generally for piping whose nominal diameter is NPS 2 or smaller.
The dimensional standards for taper pipe threads are given in ASME B1.20.1. That document gives all required dimensions including number of threads per inch, pitch diameter, and normal engagement lengths for all pipe diameters.

  • Threaded piping is commonly used in low-cost, noncritical applications such as domestic water, fire protection, and industrial cooling water systems.
  • Threaded fittings are normally made of cast gray or malleable iron, cast brass or bronze, or forged alloy and carbon steel.
  • They are available in three pressure ratings: Class 2000, 3000 and 6000.

Npt thread

All fittings on this page are described, are provided with NPT thread, ASME B1.20.1. The American National Pipe Thread Tapered, is the best known and most widely used connection where the pipe thread provides both the mechanical joint and the hydraulic seal.

Advantages and disadvantages of threaded pipe fittings

Advantages

  • Installation productivity is moderately high, and specialized installation skill requirements are not extensive.
  • Leakage integrity is good for low-pressure, low-temperature installations where vibration is not encountered.

Disadvantages

  • Rapid temperature changes may lead to leaks due to differential thermal expansion between the pipe and fittings.
  • Vibration can result in fatigue failures of screwed pipe joints due to the high stress intensification effects caused by the sharp notches at the base of the threads.
  • In hazardous piping systems threaded connections should be avoided, if possible. Their vulnerability to fatigue damage is significant, especially where exposed threads are subject to corrosion.

Outlet Pipe Fittings

Olet pipe fittings (otherwise called Branch Connection Fittings or Outlet fittings) will be fittings which give an outlet from a bigger pipe to a smaller one (or one of a similar size). The fundamental pipe onto which the branch association is welded is generally called the Run or Header size estimate. The pipe to which the branch association or connection gives a channel is normally called the Branch or Outlet size. Branch associations are in all sizes, sorts, bores, and classes, in an extensive variety of stainless steel, chrome-moly, and different amalgams alloys.

Different types of Olet or Outlet Pipe Fittings:

1) Brazolet (Brazo Outlet)
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Brazolet is utilized generally abroad as of late, it is utilized to interface or connect the fortified fittings. It happens of conventional associating ways. The assortment of Brazolet is made in phenomenal Forgings. It’s intended for use with KLM and IPS metal or copper tubing. It’s accessible with socket or threaded connections.

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Brazolet for IPS Pipe
ASME SB-98 UNS C665500 Alloy A
Outlet Sizes A B C Brazing Surface F-MIN. MIL-1183
1/4 11/16 1 9/16 0.188 0.700
3/8 13/16 1 1/4 3/4 0.190 0.855
1/2 1 1 7/16 7/8 0.220 1.020
3/4 1 1/16 1 3/4 1 1/8 0.240 1.250
1 1 1/4 2 1/8 1 7/16 0.270 1.535
1 1/4 1 5/16 2 9/16 1 3/4 0.300 1.900
1 1/2 1 3/8 2 7/8 2 0.330 2.160
2 1 1/2 3 1/2 2 9/16 0.360 2.675
2 1/2 1 13/16 4 1/8 3 0.384 3.215
3 2 4 13/16 3 11/16 0.442 3.880
4 2 1/4 6 4 3/4 0.476 4.940
5 2 5/8 7 1/16 5 9/16 0.656 6.163
 
Brazolet for Tubing
Type K, L, and M Tubing. ASME SB-98 UNS C65500 Alloy A
Outlet Sizes A B C Brazing Surface F-MIN. MIL-1183
1/4 11/16 1 9/16 0.188 0.700
3/8 13/16 1 1/4 3/4 0.190 0.855
1/2 13/16 1 1/4 3/4 0.190 0.855
3/4 1 1 7/16 7/8 0.220 1.020
1 1 1/16 1 3/4 1 1/8 0.240 1.250
1 1/4 1 1/4 2 1/8 1 7/16 0.270 1.535
1 1/2 1 5/16 2 9/16 1 3/4 0.300 1.900
2 1 3/8 2 7/8 2 0.330 2.160
2 1/2 1 1/2 3 1/2 2 9/16 0.360 2.675
3 1 13/16 4 1/8 3 0.384 3.215
4 2 1/8 5 1/2 4 5/16 0.437 4.400

2) Coupolet (Coupling Outlet)
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Coupolet pipe fittings are intended for use in flame/fire insurance sprinkler frameworks and other low weight pressure piping applications. Produced with NPT female threads for 300# administration and are UL Listed and F.M. affirmed. 

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300# Female Threaded Coupolet
Nominal
Outlet Size
Dimensions
A C F
1/2 15/16 0.745 1.188
3/4 1 0.958 1.441
1 1 3/16 1.188 1.562
1 1/4 1 5/16 1.550 1.906
1 1/2 1 9/16 1.780 2.188
2 1 11/16 2.260 2.750
2 1/2 1 13/16 2.890 3.386
3 2 1/2 3.400 4.000
4 3 4.380 5.000
Interchangeability or Combination of Sizes
Coupolet Outlet
Size Inches
Run Sizes
1/2 1/2 3/4 1-1/4 -1 2-1/2 – 1-1/2 8-3 36-10          
3/4 3/4 1 2 – 1-1/4 6 – 2-1/2 36-8            
1 1 1-1/4 2 – 1-1/2 4 – 2-1/2 8-5 36-10          
1-1/4 1-1/4 1-1/2 2-1/2 – 2 4-3 8-5 36-10          
1-1/2 1-1/2 2 2-1/2 4-3 8-5 16-10 36-18        
2 2 2 1/2 3 3-1/2 4 5 6 8 10 16-12 36-18
2-1/2 2-1/2 3 3-1/2 4 5 6 8 12-10 16-14 36-18  
3 3 3-1/2 4 5 6 8 10 12 14 18-16 36-20
4 5 6 8 10 14-12 16 18 20 24 36  

3) Elbolet (Elbow Outlet)
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Elbolet is used on 90° Long Radius Elbows (can be manufactured for Short Radius Elbows) for thermowell and instrumentation connections. Available butt-weld to meet specific reinforcement requirements, and 3000# and 6000# classes for Socket Weld and threaded applications.
An Elbolet is used on 90° long radius elbows, short radius elbows and can be used on 180° returns. However, an Elbolet on a short radius elbow is not used often. It typically is used for Thermowell and instrumentation connections but can be used as a drain connection when room isn’t available for using a Weldolet. The Elbolet is available with buttweld, socketweld or threaded connections.
Outlet is used widely abroad in recent years, It is used to connect the reinforced fittings. It can replace the reducing tee, reinforce plate and reinforced pipe. It is used widely more and more in high pressure high temperature large diameter and thick wall pipe. As it is reliability, cheap, simple, good for flow, seriation, standardization and choose easily. It takes place of traditional connecting ways. The body of outlets is made in excellent Forgings. The material is same as pipe’s. We can make outlet from Carbon steel, Alloy steel and Stainless steel. branch or other fittings such as nipple thread plug, Instrument and valve by Butt Welding, Socket Welding and Threaded.

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Nominal
Elbow Size
Inches
Outlet Size
Inches
Dimensions
CL 3000 Threaded &
Socket Weld Std. & XS Butt-Weld
CL 6000 Threaded &
Socket Socket-Weld Sch. 160 & XXS Butt-Weld
C E C E
36 – 3/4 1/4 1 1/2 1 19/32 1 1/2 1 19/32
36 – 3/4 3/8 1 1/2 1 19/32 1 1/2 1 19/32
36 – 3/4 1/2 1 1/2 1 19/32 1 23/32 1 7/8
36 – 1 3/4 1 23/32 1 7/8 2 1/4 2 1/4
36 – 2 1 2 1/4 2 1/4 2 7/8 2 1/2
36 – 2 1 1/4 2 7/8 2 1/2 3 1/8 2 11/16
36 – 2 1 1/2 3 1/8 2 11/16 4 3/16 3 1/4
36 – 3 2 4 3/16 3 1/4    
  **2 1/2 4 3/16 3 1/4    
  **3 5 1/16 3 7/8    
Order to Specific **4 6 5/8 4 13/16    
Elbow Sizes **6 9 3/8 6 1/2 ** **
  **8 13 5/16 8 1/16    
  **10 17 1/32 10 3/8    
  **12 19 5/8 11 1/8  


4) Flexolet (
Flexo Outlet)

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Flexolets are like weldolets with a minor distinction i.e. flexolet has straight bore while weldolet has decreased bore. We give flexolets butt weld, socket weld and threaded ends. Hence, you can pick any of them as per the piping applications.

What is the difference between weldolet and flexolet?

All Weldolets are Flexolets but not all Flexolets are Weldolets in the same way that all dogs are animals but not all animals are dogs.

The Flexolet and the Weldolet products are our two branch connection designs. They perform the same function, which is that they reinforce the strength lost when a hole is cut into the header pipe and they connect the header pipe to the branch pipe. The difference in designs is that the Weldolet has a tapered bore while the Flexolet has a straight-through bore. 

See below:

The tapered bore provides a better transition (reduces the flow resistance) and it also provides a lower stress intensification factor, which results in less stress on the welds and longer fatigue life. The straight-through bore decreases the diameter of the part and allows for larger run-size consolidations (meaning you can use them on a wider range of header pipe diameters). Because of the smaller size of the straight-through bore, the Flexolet tends to be less expensive as compared to the Weldolet.

5) Insert Weldolet (Insert Welding Outlet)
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Insert Weldolet is the most widely recognized of all branch connections, and is welded onto the outlet pipe. The ends are slanted to encourage this procedure, and in this manner the weldolet is viewed as a butt-weld fitting. Weldolets are intended to limit stretch fixations and give essential fortification / reinforcement.

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Outlet
Size

A’ Dimensions (Height

 above run pipe)

1 1/2 2 2 1/2 3 4 5 6 8 10 12 14 16 18 20 24
Std Wt Run Pipe 1.50 1.50 1.62 1.75 2.00 2.25 2.38 2.75 3.06 3.38 3.50 3.75 3.81 4 4.56
XS Run Pipe 1.50 1.50 1.62 1.75 2.00 2.25 3.06 3.87 3.69 4.06 3.81 4.19 4.38 4.69 5.50
.500″ to .750″ Thick Run Pipe 2.88 3.31 3.75 4.12 4.18 4.25 4.37 4.50 4.69 5.13 5.62 6.50
.750″ to 1.00″ Thick Run Pipe 3.22 3.38 3.75 4.34 4.62 4.84 5.10 5.25 5.88 6.50 6.75 7.62
1.00″ to 1.25″ Thick Run Pipe 3.38 3.50 4.00 4.50 4.88 5.00 5.38 5.50 6.00 6.50 7.00 8.00
1.25″ to 1.50″ Thick Run Pipe 3.62 3.87 4.25 4.69 5.16 5.31 5.68 5.81 6.44 6.50 7.56 8.72
 
Outlet
Size

*’W’ Dimensions (Max. O.D. of fitting

 – Max. size of hole)

1 1/2 2 2 1/2 3 4 5 6 8 10 12 14 16 18 20 24
Std Wt Run Pipe 3.50 4.25 4.88 5.69 7.00 8.06 9.71 11.71 14.00 16.32 17.56 19.75 22.00 24.00 29.00
XS Run Pipe 3.56 4.38 5.00 5.75 7.12 8.25 10.44 13.44 14.25 16.56 18.00 20.00 22.44 25.00 30.32

6) Latrolet (Lateral Outlet)
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Latrolets are a variety of weldolets. You have to connect it in same way, however these Latrolets make a 45-degree connection to the principle pipe instead of a 90 degree. These olets can be either butt welded, socket welded, or threaded.

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Nominal
Run Pipe
Size

Outlet

 Size

Dimensions

CL 3000 Threaded 

and Socket Weld

CL 6000 Threaded 

and Socket Weld

Standard & 

XS Butt Weld

Sch. 160 and 

XXS Butt Weld

A B C E A B C E A B C E A B C
2 1/2 – 1 1/4 1/4 1 9/16 2 11/32 1 7/16 1 9/16 1 9/16 2 11/32 1 7/16 1 9/16 1 5/16 2 3/32 1 7/16 1 9/16 1 9/16 2 5/16 1 7/16
12 – 3                                
2 1/2 – 1 1/4 3/8 1 9/16 2 11/32 1 7/16 1 9/16 1 9/16 2 11/32 1 7/16 1 9/16 1 5/16 2 3/32 1 7/16 1 9/16 1 9/16 2 5/16 1 7/16
12 – 3                                
2 1/2 – 1 1/4 1/2 1 9/16 2 11/32 1 7/16 1 9/16         1 3/8 2 5/32 1 7/16 1 9/16      
12 – 3                                
1 1/2 – 1 1/4                                
5 – 2 1/2         1 7/8 2 3/4 1 3/4 1 29/32         1 13/16 2 3/4 1 3/4
12 – 6                                
1 1/2 – 1 1/4                                
5 – 2 3/4 1 7/8 2 3/4 1 3/4 1 29/32         1 11/16 2 17/32 1 3/4 1 29/32      
12 – 6                                
2 1/2 – 2                                
5 – 3 3/4         2 3/16 3 1/4 2 1/8 2 3/16         2 1/8 3 1/4 2 1/8
12 – 6                                
2 1/2 – 2                                
5 – 3 1 2 3/16 3 1/4 2 1/8 2 3/16 2 1/2 3 21/32 2 5/8 2 15/32 1 31/32 3 2 1/8 2 3/16 2 1/2 3 13/16 2 5/8
12 – 6                                
2 1/2 – 2                                
5 – 3 1 1/4 2 1/2 3 27/32 2 5/8 2 15/16 2 3/4 4 7/32 3 1/32 2 5/8 2 9/32 3 19/32 2 5/8 2 15/32 2 3/4 4 1/4 3
12 – 6                                
2 1/2 – 2                                
5 – 3 1 1/2 2 3/4 4 7/32 3 1/32           2 15/32 3 31/32 3 1/32 2 5/8      
12 – 6                                
5 – 4                                
8 – 6 1 1/2         3 3/8 5 7/16 4 1/8 3 5/32         3 3/8 5 3/8 4 1/8
12 – 10                                
5 – 4                                
8 – 6 2 3 3/8 5 7/16 4 1/8 3 5/32 3 3/8 5 7/16 4 1/8 3 5/32 3 3/16 5 1/4 4 1/8 3 13/32      
12 – 10                                
5 – 4                                
8 – 6 2 1/2                 3 5/32 5 3/16 4 1/8 3 5/32      
12 – 10                                
Order to
Specific Run
Pipe Sizes
                               
3                 3 13/16 6 1/4 4 31/32 3 25/32      
                               
Order to
Specific Run
Pipe Sizes
                               
4                 4 3/4 7 13/16 6 7/16 4 9/16      
                             

7) Nipolet (Nipple Outlet)
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Nipolets is only a blend of olets with nipples. These olets work like the weldolets or threadolets, yet are with nipple. They come either with a plain end or a threaded end. You can utilize either as indicated by the applications. Nipolets are broadly utilized for vents, taps, or depletes (drains).

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Plain end and Threaded
Size 1/2 3/4 1 1 1/4 1 1/2 2
XS A 3 1/2 3 1/2 3 1/2 3 1/2 3 1/2 3 1/2
C 15/16 1 3/16 1 7/16 1 3/4 2 2 9/16
XXS A 3 1/2 3 1/2 3 1/2 3 1/2 3 1/2 3 1/2
C 9/16 3/4 1 1 5/16 1 1/2 1 11/16

8) Sockolet (Socket Weld Outlet)
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Sockolet is the same basic design as a “weldolet” or “threadolet” where the major difference is that a Sockolet has a socket for welding versus a buttweld connection that a Weldolet has. This makes a 90° branch and comes in full size or reducing for a straight piece of pipe. Sockolets are available in Class 3000, 6000 and 9000 for high pressures.

What is the difference between a weldolet and a sockolet?

The weldolet and the sockolet both have a run end and a branch end. The run end connects to the larger diameter pipe, and the branch end connects to the smaller diameter pipe. The connection to the run pipe is a fillet weld for both the weldolet and the sockolet. They differ, however, at the connection to the branch pipe. The weldolet has a bevelled end to butt weld to the branch pipe (which will also have a bevelled end), whereas the sockolet has a socket into which a plain end branch pipe is inserted, then fillet welded together.

Dimensions Reducing Sockolets – MSS SP97

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CLASS 3000

NPS A B C D E
1/2 1
25.40
1.13/32
35.71
29/32
23.01
0.622
15.80
9/16
14.28
3/4 1.1/16
26.98
1.23/32
43.65
1.5/32
29.36
0.824
20.93
9/16
14.28
1 1.5/16
33.33
2
50.8
1.7/16
36.51
1.049
26.64
25/32
19.84
1.5/16
33.33
2.9/16
65.08
1.3/4
44.45
1.380
35.05
3/4
19.05
1.3/8
34.92
2.27/32
72.23
2
50.8
1.610
40.89
3/4
19.05
2
38.1
3.15/32
88.10
2.9/16
65.08
2.067
52.50
13/16
20.63
1.9/16
39.68
4.1/16
103.18
3
76.2
2.469
62.71
3/4
19.05
3 1.3/4
44.45
4.13/16
122.23
3.11/16
93.66
3.068
77.93
15/16
23.81
1.11/16
42.86
5.3/8
136.52
4.7/16
112.71
3.548
90.12
11/16
17.46
4 1.7/8
47.62
5.31/32
151.60
4.3/4
120.65
4.026
102.26
1.1/16
26.98
5 2.5/8
66.67
7.5/16
185.73
5.9/16
141.28
5.047
128.19
1.11/32
34.13
6 2.3/4
69.85
8.5/8
219.07
6.11/16
169.86
6.065
154.05
1.13/32
35.71
X = Min. 1/16 (1.6 mm)

CLASS 6000

NPS A B C D E
1/2
31.75
1.23/32
43.65
3/4
19.05
0.466
11.84
7/8
22.22
3/4 1.7/16
36.51
1.61/64
49.60
1
25.4
0.614
15.60
7/8
22.22
1 1.9/16
39.68
2.7/16
61.91
1.5/16
33.33
0.815
20.70
15/16
23.81
1.5/8
41.27
2.23/32
69.05

38.1
1.160
29.46
13/16
20.63
1.11/16
42.86

82.55
1.15/16
49.21
1.338
33.99
7/8
22.22
2 2.1/16
52.38
4.1/32
102.39
2.3/4
69.85
1.689
42.90
1.3/16
30.16
X = Min. 1/16 (1.6 mm)
General notes:
  • Dimensions: Top Row in Inches / Bottom Row in millimeters.
  • Bottoming Clearance – X – The purpose for the bottoming clearance in a Socket Weld is usually to reduce the residual stress at the root of the weld that could occur during solidification of the weld metal, and to allow for differential expansion of the mating elements.
  • Socket dimensions are in accordance with ASME B16.11. Design per MSS SP-97.
  • Source comes from Bonney Forge (except the sizes in millimeters).
  • Sockolet® is a registered name. Another often used name is Socket Weld Outlet.

9) Sweepolet (Swept Outlet)

20171225075818 88733 - What are pipe fittings

Sweepolet is a shaped, essentially fortified; butt-weld branch association with a low stress escalation factor for low burdens and long exhaustion life. The connection weld is effectively inspected by radiography, ultrasound and other standard non-damaging methods. It’s produced to meet your particular support prerequisites. It reduces the stress concentration factors and pipe stresses.

20171225084008 71211 - What are pipe fittings

Run Size Outlet Size
Inches
Dimensions
*A B
6 to 36 1 1/4 1 1/4 4
6 to 36 1 1/2 1 3/4 5 1/2
6 to 36 2 1 1/2 5 1/2
6 to 36 3 1 21/32 7
6 to 36 4 2 1/32 8 3/4
10 to 36 6 2 11/16 13
12 to 36 8 3 15
16 to 36 10 3 1/8 18 1/2
16 to 36 12 3 5/16 20 1/2
20 to 36 14 3 5/8 24
24 to 36 16 3 3/4 28
24 to 36 18 4 5/8 31
24 to 36 20 5 1/8 33
30 to 36 24 5 5/8 38


Weldolet
 Vs Sweepolet

Weldolets (aka WOL) are cheaper in terms of purchasing cost than sweepolets (aka SOL).

WOLs may, in some situations (large dia, thin wall) warp the pipe, i.e. unstraight and oval, due to excessive heat input arising form the relative thick required weld metal layer.

Since for WOLs the weld metal thickness is always greater than for SOLs (where one only welds the base metal wall thickness), welding may require some extra time to allow cooling off on the heat input to prevent banana-warping the pipe.

SOLs are less standard, I think most of the time custom made. Without having specific experience with SOLs, preparing and beveling the pipe for it may be more difficult/time-costuming compared to WOLs. For WOLs, you can weld them on, and then bore through the hole. This gives a smooth weld profile on the inside. This may give the best option for a flushing branch, as there is not weld metal ‘sticking into the run’ (provided the pipe doesnt become oval, as this will cause the pig trap to become stuck perhaps).

Since the saddle form is quite specific (but then again, the SOL may be laid down on the pipe, and the contour can be drawn), and a lot bigger than WOLs, more material has to be removed. 

If you use a SOL and the run pipe is large enough in dia, you may counter grind the root weld to become flush.

WOLs can be RT-ed, SOLs can.

WOLs are likely to give more peak stress than SOLs, since the latter has a much more continuous profile into the branch.

10) Threadolet (Threaded Outlet)
20171225080236 82165 - What are pipe fittings

threadolet is the same basic design as a “weldolet.” However the main difference is the fitting has a female threaded connection to mate to the branch connection. This makes a 90° branch and comes in full size or reducing for a straight piece of pipe. It typically is in the size range of 1/2″ to 2″ and is welded over a hole either drilled or burned in the pipe. 

You use a “weldolet” when you want to weld a pipe or fitting directly to the branch fitting and a “threadolet” when you want to screw the connecting pipe or fitting (e.g. valve) to the branch connection.

I believe there is a ANSI standard for the dimensions and pressure rating of these type of fitting. 

Depending of the relative size of the olet and the main pipe run the affect can vary from no affect to causing the header to bow or warp due to the heating and cooling of the weld. A good run of thumb is to never use an olet that is larger that 1/2 the size of the main pipe run. Size in this case being the nominal size.

Dimensions Reducing Thredolet – MSS SP97

20171225084236 36797 - What are pipe fittings

CLASS 3000

NPS A B C
1/2 1
25.40
1.13/32
35.71
15/16
23.81
3/4 1.1/16
26.98
1.23/32
43.65
1.5/32
29.36
1 1.5/16
33.33
2
50.80
1.7/16
36.51
1.5/16
33.33
2.9/16
65.08
1.3/4
44.45
1.3/8
34.92
2.27/32
72.23
2
50.80
2
38.10
3.15/32
88.10
2.9/16
65.08
1.13/16
46.03
4.1/16
103.18
3
76.20
3 2
50.80
4.13/16
122.23
3.11/16
93.66
2.1/8
53.975
5.7/32
132.55
4
101.6
4
57.15
5.31/32
151.60
4.3/4
120.65
5 2.5/8
66.67
7.5/16
185.73
5.9/16
141.28
6 2.3/4
69.85
8.5/8
219.07
6.11/16
169.86
NPS A B C

CLASS 6000

NPS A B C
1/2
31.75
1.23/32
43.65
3/4
19.05
3/4 1.7/16
36.51
1.61/64
49.60
1
25.40
1 1.9/16
39.68
2.7/16
61.91
1.5/16
33.33
1.5/8
41.27
2.23/32
69.05

38.10
1.11/16
42.86

82.55
1.15/16
49.21
2 2.1/16
52.38
4.1/32
102.39
2.3/4
69.85
NPS A B C
General notes:
  • Dimensions: Top Row in Inches / Bottom Row in millimeters.
  • Root Gap – X – “Space” for welding the O’let is raised off the run pipe to establish proper weld gap by placing spacers, e.g. welding rods, under the fitting. This provides a uniform welding gap between the curvature of the run and base of fitting.
  • Threaded Ends are in accordance with ASME B1.20.1. Design per MSS SP-97.
  • Source comes from Bonney Forge (except the sizes in millimeters).
  • Thredolet is a registered name. Another often used name is Threaded Outlet.

11) Weldolet (Welding Outlets)
20171225080312 37087 - What are pipe fittings

Weldolet (Welding Outlet) is the most common of all branch connections, and is welded onto the outlet pipe. The ends are bevelled to facilitate this process, and therefore the weldolet is considered a butt-weld fittingWeldolet (Welding Outlet) is designed to minimize stress concentrations and provide integral reinforcement. manufactured to meet your specific reinforcement requirements.

What is a weldolet (Welding Outlet)?

A Weldolet is commonly known on drawings as a WOL and makes a 90° branch connection. It comes in full size or reducing for a straight piece of pipe. A weldolet is designated by the run length by the branch length. For example a 6-inch weldolet on a 19-inch pipe would be a 19×6 Weldolet. 

Dimensions Weldolet Size on Size -STD- MSS SP97
20171225084453 45446 - What are pipe fittings

DIMENSIONS NPS 1/2 TO 24

NPS A B C D
1/2 3/4
19.05
1.3/8
34.93
15/16
23.81
5/8
15.88
3/4 7/8
22.23
1.5/8
41.28
1.3/16
30.16
13/16
20.64
1 1.1/16
26.99
2
50.80
1.7/16
36.51
1.1/32
26.19

31.75
2.3/8
60.3
1.3/4
44.45
1.3/8
34.93
1.5/16
33.34
2.7/8
73
2
50.80
1.5/8
41.28
2
38.10

88.90
2.9/16
65.09
2.1/16
52.39
1.5/8
41.28
4.1/16
103.19
3
76.20
2.7/16
61.91
3 1.3/4
44.45
4.13/16
122.24
3.11/16
93.66
3.1/16
77.79
2
50.80
5.3/8
136.53
3.7/8
98.43
3.9/16
90.49
4 2
50.80
6
152.40
4.3/4
120.65
4
101.60
5
57.15
7.1/8
180.98
5.9/16
141.29
5.1/16
128.59
6 2.3/8
60.3

215.90
6.11/16
169.86
6.1/16
153.99
8 2.3/4
69.85
10.3/8
263.53
8.11/16
220.66
7.15/16
201.61
10 3.1/16
77.79
12.9/16
319.09
10.13/16
274.64
10
254.00
12 3.3/8
85.73
14.7/8
377.83
12.13/16
325.44
12
304.80
14
88.90
16.1/8
409.58
14.1/16
357.19
13¼
336.55
16 3.11/16
93.66
18¼
463.55
16.1/16
407.99
15¼
387.35
18 4.1/16
103.19
20.3/4
527.05
18.5/8
473.08
17¼
438.15
20 4.5/8
117.48
23.1/16
585.79
20.1/16
509.59
19¼
488.95
24 5.3/8
136.53
27.7/8
708.03
25.1/8
638.18
23¼
590.55
NPS A B C D
General notes:
  • Dimensions: Top Row in Inches / Bottom Row in millimeters.
  • Root Gap – X – “Space” for welding the O’let is raised off the run pipe to establish proper
    weld gap by placing spacers, e.g. welding rods, under the fitting. This provides a uniform
    welding gap between the curvature of the run and base of fitting.
  • L = Dimensions Center Line of Run Pipe + X (Root Gap) + A (height of Weldolet).
  • Bevelled Ends ASME B16.9 and B16.25.
  • Source comes from Bonney Forge (except the sizes in millimeters).
  • Weldolet is a registered name. Another often used name is Welding Outlet.

Outlet Pipe Fittings Classes as per this standadrd are : 

  1. Standard : Buttwelding : 1/8″ to 24″, for connecting STD thk Pipe.
  2. Extra Strong : Buttwelding : 1/8″ to 24″ for connecting Extra Strong Pipe
  3. Schedule 160 : Buttwelding : 1/2″ to 6″ : for connecting Schedule 160 Pipe
  4. 3000 : Threaded and Socket Welding : 1/8″ to 4″ : for connecting Extra Strong Pipe
  5. 6000 : Threaded and Socket Welding : 1/2″ to 2″ : for connecting Sch 160 Pipe.

Material

  • Carbon steel
  • Stainless steel
  • Other

Specifying the Schedule of both the Run and Branch

Generally the schedules of the run pipe and branch pipe are identical and thus specification of the equivalent schedule Weldolet assures the proper fitting being used.

EXAMPLE:
16″ Standard weight x 6″ Standard weight is specified as a 6″ standard weight fitting.
Where the schedule of the run is greater or less than the schedule of the branch, it is essential that both schedules be specified since (a) The Weldolet’s reinforcing characteristics are a function of the run pipe wall thickness, which in turn designates the schedule of the basic Weldolet fitting to be used;(b) The wall thickness of the outlet or branch end must match the wall thickness of the branch pipe.

EXAMPLE:
16″ Extra strong x 6″ Standard weight
16″ Standard weight x 6″ Extra strong
Special care is suggested to avoid confusing schedule 40 and standard weight as being identical (above 10″ schedule 40 is heavier) and schedule 80 and extra strong (above 8″ schedule 80 is heavier).

By material

Special Alloys

  • Hastelloy® X
  • Monel® R-405
  • Monel® K-500
  • Hastelloy® C-276
  • Hastelloy® C-22
  • Hastelloy® B-2
  • Incoloy® 825
  • Incoloy® 800h / 800ht®
  • Inconel® 718
  • Inconel® Alloy 625
  • Inconel® Alloy 601
  • Inconel® Alloy 600
  • Monel® Alloy 400
  • Alloy 20
  • Nickel 200/201
  • Monel® R-405
  • Monel® K-500
  • Monel® Alloy 400
  • Inconel® 718
  • Inconel® Alloy 625
  • Inconel® Alloy 601
  • Inconel® Alloy 600
  • Incoloy® 825
  • Hastelloy® X
  • Hastelloy® C-276
  • Hastelloy® C-22
  • Hastelloy® B-2
  • Incoloy® 800h / 800ht®
  • Hastelloy® B-3

Duplex Stainless Steel

  • Zeron® 100, Super Duplex Stainless Steel
  • Super Duplex S32760
  • Ldx 2101®, Duplex Steel
  • Duplex S31803
  • Super Duplex 2507
  • Duplex 2205

Stainless Steel

  • Stainless Steel Nitronic 50hs
  • Stainless Steel Nitronic 60
  • Stainless Steel Nitronic 50
  • Stainless Steel 13-8ph
  • Stainless Steel 15-5ph
  • Stainless Steel Prodec 303
  • Stainless Steel 303
  • Stainless Steel 446
  • Stainless Steel 410s
  • Stainless Steel 410
  • Stainless Steel 304-304h
  • Stainless Steel 17-4
  • Stainless Steel 347
  • Stainless Steel 440c
  • Stainless Steel 309
  • Stainless Steel 316-316l
  • Stainless Steel Al-6xn®
  • Stainless Steel 330
  • Stainless Steel 321
  • 317l Stainless Steel
  • Stainless Steel 310/310s
  • Stainless Steel 304l
  • Stainless Steel 304
  • Stainless Steel 253 Ma

Carbon Steel

  • A-36, 204
  • Sa-283, 285
  • A-572, A-514, 515
  • A-516, A-537
  • A-572
  • A-588
  • 1008, 1010
  • 1015, 1045, 1060
  • Api-5, A53
  • A106b
  • A179, A209
  • A36, 1018, 1020
  • 1044, 1045
  • 1117, 11l17
  • 1035, 1141l
  • A36
  • A588gra
  • A105, WPB, WPC

Titanium

  • 10v-2fe-3al
  • 6al-4v
  • 6al-4v Sta
  • 6al-4v Eli
  • 6al-2sn-4zr-2mo

Cobalt

  • Waspaloy®
  • Tribaloy®t-800®
  • René 41
  • L605
  • C263
  • 694 (cm-64)
  • 188

Standards of pipe fittings:

Some widely used pipe fitting standards are as follows:

ASME: 
American Society for Mechanical Engineers

This is one of the reputed organizations in the world developing codes and standards.

The schedule number for pipe fitting starts from ASME/ANSI B16. The various classifications of ASME/ANSI B16 standards for different pipe fittings are as follows:

  • ASME/ANSI B16.1 – 1998 – Cast Iron Pipe Flanges and Flanged Fittings
  • ASME/ANSI B16.3 – 1998 – Malleable Iron Threaded Fittings
  • ASME/ANSI B16.4 – 1998 – Cast Iron Threaded Fittings
  • ASME/ANSI B16.5 – 1996 – Pipe Flanges and Flanged Fittings
  • ASME/ANSI B16.11 – 2001 – Forged Steel Fittings, Socket-Welding and Threaded
  • ASME/ANSI B16.14 – 1991 – Ferrous Pipe Plugs, Bushings and Locknuts with Pipe Threads
  • ASME/ANSI B16.15 – 1985 (R1994) – Cast Bronze Threaded Fittings
  • ASME/ANSI B16.25 – 1997 – Buttwelding Ends
  • ASME/ANSI B16.36 – 1996 – Orifice Flanges etc.

This is one of the largest voluntary standards development organizations in the world. It was originally known as the American Society for Testing and Materials (ASTM).

  • ASTM A105 / A105M – Specification for Carbon Steel Forgings for Piping Applications
  • ASTM A234 / A234M – Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
  • ASTM A403 / A403M – Specification for Wrought Austenitic Stainless Steel Piping Fittings
  • ASTM A420 / A420M – Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Low-Temperature Service

AWWA About – Established in 1881, the American Water Works Association is the largest nonprofit, scientific and educational association dedicated to managing and treating water, the world’s most important resource.

  • AWWA C110 – Ductile-Iron and Gray-Iron Fittings, 3 Inch Through 48 Inch (75 mm Through 1200 mm), for Water and Other Liquids
  • AWWA C208 – Dimensions for Fabricated Steel Water Pipe Fittings

The American National Standards Institute
ANSI is a private, non-profit organization. Its main function is to administer and coordinate the U.S. voluntary standardization and conformity assessment system. It provides a forum for development of American national standards. ANSI assigns “schedule numbers”. These numbers classify wall thicknesses for different pressure uses.

MSS STANDARDS 
Manufacturers Standardization Society

The Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry is a non-profit technical association organized for development and improvement of industry, national and international codes and standards for: Valves, Valve Actuators, Valve Modification, Pipe Fittings, Pipe Hangers, Pipe Supports, Flanges and Associated Seals

  • MSS SP-43 – Wrought Stainless Steel ButtWelding Fittings Including Reference to Other Corrosion Resistant Materials
  • MSS SP-75 – Specifications for High Test Wrought Buttwelding Fittings
  • MSS SP-73 – Brazing Joints for Copper and Copper Alloy Pressure Fittings
  • MSS SP-83 – Class 3000 Steel Pipe Unions, Socket-Welding and Threaded
  • MSS SP-97 – Integrally Reinforced Forged Branch Outlet Fittings — Socket Welding, Threaded, and Buttwelding Ends
  • MSS SP-106 – Cast Copper Alloy Flanges and Flanged Fittings Class 125,150, and 300
  • MSS SP-119 – Factory-Made Wrought Belled End Socket Welding Fittings

Difference between “Standard” and “Codes”:

Piping codes imply the requirements of design, fabrication, use of materials, tests and inspection of various pipe and piping system. It has a limited jurisdiction defined by the code. On the other hand, piping standards imply application design and construction rules and requirements for pipe fittings like adapters, flanges, sleeves, elbows, union, tees, valves etc. Like a code, it also has a limited scope defined by the standard.

Factors affecting standards:

“Standards” on pipe fittings are based on certain factors like as follows:

  • Pressure-temperature ratings
  • Size
  • Design
  • Coatings
  • Materials
  • Marking
  • End connections
  • Dimensions and tolerances
  • Threading
  • Pattern taper etc.

BSP is the U.K. standard for pipe fittings. This refers to a family of standard screw thread types for interconnecting and sealing pipe ends by mating an external (male) with an internal (female) thread. This has been adopted internationally. It is also known as British Standard Pipe Taper threads (BSPT )or British Standard Pipe Parallel (Straight) threads (BSPP ). While the BSPT achieves pressure tight joints by the threads alone, the BSPP requires a sealing ring.

This is the Japanese industrial standards or the standards used for industrial activities in Japan for pipe, tube and fittings and published through Japanese Standards Associations.

National Pipe Thread is a U.S. standard straight (NPS) threads or for tapered (NPT) threads. This is the most popular US standard for pipe fittings. NPT fittings are based on the internal diameter (ID) of the pipe fitting.

We are manufacturer of Flange bolts & Nuts and supply high quality

  • A193 = This specification covers alloy and stainless steel bolting material for pressure vessels, Valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications.
  • A320 = Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for Low-Temperature Service.
  • A194 = Standard specification for nuts in many different material types.

AN:
Here, “A” stands for Army and “N” stands for Navy

The AN standard was originally designed for the U.S. Military. Whenever, a pipe fitting is AN fittings, it means that the fittings are measured on the outside diameter of the fittings, that is, in 1/16 inch increments.

For example, an AN 4 fitting means a fitting with an external diameter of approximately 4/16″ or ¼”. It is to be noted that approximation is important because AN external diameter is not a direct fit with an equivalent NPT thread.

Dash (-) size

Dash size is the standard used to refer to the inside diameter of a hose. This indicates the size by a two digit number which represents the relative ID in sixteenths of an inch. This is also used interchangeably with AN fittings. For example, a Dash “8” fitting means an AN 8 fitting.

ISO is the industrial pipe, tube and fittings standards and specifications from the International Organization for Standardization. ISO standards are numbered. They have format as follows:

“ISO[/IEC] [IS] nnnnn[:yyyy] Title” where

  • nnnnn: standard number
  • yyyy: year published, and
  • Title: describes the subject
A STANDARD HOSE GUIDE IS GIVEN
Hose Size In Nominal ID Inch Dash Size Standard Dash Size
1/4 3/16 -04
3/8 5/16 -06
1/2 13/32 -08
3/4 5/8 -12
1 7/8 -16
1 ½
1 ¼ 1 1/8 -20

Flanges: Ratings in Classes and Pressure Numbers (PN)

Flange Class 150 300 600 900 1500 2500
Flange Pressure Number, PN 20 50 100 150 250 420

Production process of pipe fittings

① Blanking
The pipe materials is used primarily for pipe, process, and bars, the shape of the blank to select the cutting method based on the material properties and product. Blank shape, size and other requirements according to different process requirements.

② Forming (welding)
For all pipe manufacturing process, the steel pipe cross-section is an indispensable process. Due to the forming process of the different products is different, you need a longer length.

③ Heat treatment
The heat treatment process is an important part of the pipe manufacturing. Heat treatment step of heating, insulation and cooling, eliminating the forming process of hardening, residual stress and deformation defects of metal pipe after forming the metal structure, performance of a steel pipe network, restored to the state or its performance in the deformation processing will be improved.

④ Surface treatment
Pipe surface treatment is usually by sandblasting, shot blasting, grinding, pickling method to remove the product surface rust, scratches and other products to achieve a smooth surface to meet the follow-up processing, and inspection requirements.

⑤ Cutting
Cutting pipe, soldering end, structural size, geometric tolerance machining processes. Also includes some pipe cutting, the diameter of processing. The cutting machine is mainly via a dedicated machine or universal; oversized pipe, when the existing machine capacity can not meet the processing requirements, you can also use other methods to complete processing, such as large diameter elbow with gas cutting, grinding method.

⑥ Non-destructive testing
Non-destructive testing is an important process of the possible defects of the test materials and fittings processing. The majority of pipe product standards for the requirements of the non-destructive testing requirements, but requirements are not consistent. In addition to meeting the product standards and ordering requirements, nondestructive testing, more stringent on quality control factory to develop non-destructive testing requirements according to the materials, processes, and internal quality control requirements in order to ensure the quality of manufactured products.

End Beveling of pipe fittings In the behavior, we make beveling after shot blasting, bevel ends are fully machined by advanced equipment Double Beveling Machine ensure the height, length, thickness, O.D. and I.D. are all qualified.

WELDING BEVEL ACC.TO ASME / ANSI B16.9 AND ASME / ANSI B16.28

Our in-hourse R&D team developed bevel ends equipment are good using in thickness 2mm to 20mm pipe fittings, guarantee high efficiency and high quality.

Send us your technical drawings: yaang.com will supply you with whatever flanges you are looking for. 

20171214233332 15016 - What are pipe fittings

Nominal wall Thickness : t End Preparation
t<5mm (for austenitic alloy steel
t<4mm)
Cut square or slightly chamfer
at manufacturer ‘ s option
5<t<22mm
(4<t<22mm)
Plain Bevel as in sketch ( a ) above
t>22mm Compound Bevel as in sketch ( b ) above
Nominal pipe
DN size
Outside Diameter at Bevel Center to End

D1

D2

C

M

Series A Series B Series A Series B
20×15 26.9 25 21.3 18 29 29
25×20
25×15
33.7
33.7
32
32
26.9
21.3
25
18
38
38
38
38
32×25
32×20
32×15
42.4
42.4
42.4
38
38
38
33.7
26.9
21.3
32
25
18
48
48
48
48
48
48
40×32
40×25
40×20
40×15
48.3
48.3
48.3
48.3
45
45
45
45
42.4
33.7
26.7
21.3
38
32
25
18
57
57
57
57
57
57
57
57
50×40
50×32
50×25
50×20
60.3
60.3
60.3
60.3
57
57
57
57
48.3
42.4
33.7
26.9
45
38
32
25
64
64
64
64
60
57
51
44
65×50
65×40
65×32
65×25
76.1(73)
76.1(73)
76.1(73)
76.1(73)
76
76
76
76
60.3
48.3
42.4
33.7
57
45
38
32
76
76
76
76
70
67
64
57
80×65
80×50
80×40
80×32
88.9
88.9
88.9
88.9
89
89
89
89
76.1(73)
60.3
48.3
42.4
76
57
45
38
86
86
86
86
83
76
73
70
90×80
90×65
90×50
90×40
101.6
101.6
101.6
101.6



88.9
76.1(73)
60.3
48.3



95
95
95
95
92
89
83
79
100×90
100×80
100×65
100×50
100×40
114.3
114.3
114.3
114.3
114.3

108
108
108
108
101.6
88.9
76.1(73)
60.3
48.3

89
76
57
45
105
105
105
105
105
102
98
95
89
86
125×100
125×90
125×80
125×65
125×50
139.7
139.7
139.7
139.7
133
– 
133
133
133
114.3
101.6
88.9
76.1(73)
60.3
108

89
76
57
124
124
124
124
124
117
114
111
108
105
150×125
150×100
150×90
150×80
150×65
168.3
168.3
168.3
168.3
168.3
159
159 

159
159
139.7
114.3
101.6
88.9
76.1(73)
133
108

89
76
143
143
143
143
143
137
130
127
124
121
200×150
200×125
200×100
200×90
219.1
219.1
219.1
219.1
219
219
219
168.3
139.7
114.3
101.6
159
133
108
178
178
178
178
168
162
156
152
200×200
200×150
200×125
200×100
273.0
273.0
273.0
273.0
273
273
273
273
219.1
168.3
139.7
114.3
219
159
133
108
216
216
216
216
208
194
191
184
300×250
300×200
300×150
323.9
323.9
323.9
325
325
325
273.0
219.1
168.3
273
219
159
254
254
254
241
229
219
300×125 323.9 325 139.7 133 254 216
350×300
350×250
350×200
350×150
355.6
355.6
355.6
355.6
377
377
377
377
323.9
273.0
219.1
168.3
325
273
219
159
279
279
279
279
270
257
248
238
400×350
400×300
400×250
400×200
400×150
406.4
406.4
406.4
406.4
406.4
426
426
426
426
426
355.6
323.9
273.0
219.1
168.3
377
325
273
219
159
305
305
305
305
305
305
295
283
273
264
450×400
450×350
450×300
450×250
450×200
457.2
457.2
457.2
457.2
457.2
478
478
478
478
478
406.4
355.6
323.9
273.0
219.1
426
377
325
273
219
343
343
343
343
343
330
330
321
308
298
500×450
500×100
500×350
500×300
500×250
500×200
508.0
508.0
508.0
508.0
508.0
508.0
529
529
529
529
529
529
457.2
406.4
355.6
323.9
273.0
219.1
478
426
377
325
273
219
381
381
381
381
381
381
368
356
356
346
333
324
550×500
550×450
550×400
559
559
559


508
457
406


419
419
419
406
394
381
600×550
600×550
600×450
610
610
610

630
630
559
508
457

530
480
432
432
432
432
432
419
650×600
650×550
650×500
660
660
660


610
559
508


495
495
495
483
470
457
700×650
700×600
700×550
711
711
711

720
660
610
559

630
521
521
521
521
508
495
750×700
750×650
750×600
762
762
762


711
660
610


559
559
559
546
546
533
800×750
800×700
800×650
813
813
813

820
762
711
660

720
597
597
597
584
572
572
850×800
850×750
850×700
864
864
864


813
762
711


635
635
635
622
610
597
900×850
900×800
900×750
914
914
914

920
864
813
762

820 
673
673
673
660
648
635
950×900
950×850
950×800
965
965
965


914
864
813


711
711
711
711
698
686
1000×950
1000×900
1000×8500
1016
1016
1016

1020
965
914
864

920 
749
749
749
749
737
724
1000×1000
1050×950
1050×900
1067
1067
1067


1016
965
914


762
762
762
711
711
711
1100×1050
1100×1000
1100×950
1118
1118
1118

1120
1067
1016
965

1020 
813
813
813
762
749
737
1150×1100
1150×1050
1150×1000
1168
1168
1168


1118
1067
1016


851
851
851
800
787
775
1200×1150
1200×1100
1200×1050
1220
1220
1220

1220
1168
1118
1067

1120 
889
889
889
838
838
813
Nominal pipe size Outside Diameter at Bevel Center to End
D C M
DN INCH Series A Series B
15 1/2 21.3 18 25
20 3/4 26.9 25 29
25 1 33.7 32 38
32 11/4 42.4 38 48
40 11/2 48.3 45 57
50 2 60.3 57 64
65 21/2 76.1(73) 76 76
80 3 88.9 89 86
90 31/2 101.6 95
100 4 114.3 108 105
125 5 139.7 133 124
150 6 168.3 159 143
200 8 219.1 219 178
250 10 273.0 273 216
300 12 323.9 325 254
350 14 355.6 377 279
400 16 406.4 426 305
450 18 457.2 478 343
500 20 508.0 529 381
550 22 559 419
600 24 610 630 432
650 26 660 495
700 28 711 720 521
750 30 762 559
800 32 813 820 597
850 34 864 635
900 36 914 920 673
950 38 965 711
1000 40 1016 1020 749
1050 42 1067 762 711
1100 44 1118 1120 813 762
1150 46 1168 851 800
1200 48 1220 1220 889 838

END CONNECTIONS
There are four different type of connections that are used for fittings:

  1. Butt Weld Fittings – Probably the most common type of fitting. They are easily manufactured and are easily installed. Butt weld fittings can be connected directly to each other. This is called fitting make up.
  2. Flanged Fittings – Flanged fittings are piping components where the flange is an integral component of the fitting. These are most often used in water treatment applications or lined piping where welding would be destructive to the liner.
  3. Socket Weld Fittings – These fittings have a socket weld connection on each end. They might be used for smaller diameter piping. These fittings utilize a single fillet weld to join the piping with the fitting.
  4. Threaded Fittings – Threaded fittings are generally four inches and smaller. The reason for this size constraint is the pipe end needs to be threaded with a male type connection and die sizes are unobtainable in the larger diameters.

How are pipe fittings measured?

Pipe fittings are measured by their diameter, wall thickness (known as “schedule”), and shape or configuration. (Fittings are also defined by their material grade and whether they are welded or seamless.)
Diameter refers to outside diameter of a pipe or fitting.
The North American standard is known as Nominal Pipe Size (NPS). The International Standard is known as Diameter Nominal (DN). Pipes and fittings are actually made in similar sizes around the world: they are just labeled differently.
From ½ in to 12 inch “Nominal Pipe Size”, outside diameters are slightly larger than indicated size; inside diameters get smaller as schedules grow.
From 14 in and larger “Nominal Pipe Size”, outside diameters are exactly as indicated size; inside diameters get smaller as schedules grow.
As with other North American standards (inch, foot, yard, mile, …), many pipe standards (diameters up to 12 inch and wall thickness) are based on historical precedents (a toolmaker’s dies during US Civil War) rather than a “scientific” method.

SCHEDULE NUMBERS

The schedule numbers are used by the ANSI (American National Standards Institute) to denote wall thickness. The schedule numbers encompass all pipe dimensions beginning at NPS 1/8” up NPS 36”. Note that this configuration is only for fittings that match with a particular ANSI schedule number.

Nominal Pipe Size (NPS) is a North American set of standard sizes for pipes used for high or low pressures and temperatures.

  • Schedule, often shortened as sch, is a North American standard that refers to wall thickness of a pipe or pipe fitting. Higher schedules mean thicker walls that can resist higher pressures.
  • Pipe standards define these wall thicknesses: SCH 5, 5S, 10, 10S, 20, 30, 40, 40S, 60, 80, 80S, 100, 120, 140, 160, STD, XS and XXS. (S following a number is for stainless steel. Sizes without an S are for carbon steel.)
  • Higher schedules are heavier, require more material and are therefore more costly to make and install.

What does “schedule” mean for pipe fittings?
Schedule, often shortened as SCH, is a North American standard that refers to wall thickness of a pipe or pipe fitting.
What is schedule 40, SCH80?
Higher schedules mean thicker walls that can resist higher pressures.
Pipe standards define these wall thicknesses: SCH 5, 5S, 10, 10S, 20, 30, 40, 40S, 60, 80, 80S, 100, 120, 140, 160, STD, XS and XXS. 
(S following a number is for stainless steel. Sizes without an S are for carbon steel.)
Higher schedules are heavier, require more material and are therefore more costly to make and install.

Why are fittings sometimes thicker and heavier than pipes to which they are connected?
Fittings are sometimes thicker than their connecting pipes to meet performance requirements or due to manufacturing reasons.
Due to fitting geometry, stress is very different when compared to a pipe. Using extra material is often necessary to compensate for such additional stress, especially for tees and tight curve elbows.
Fitting manufacturers may not always stock plates or pipes for all metal grades or sizes. When responding to an order, manufacturers always use the right metal or alloy, but sometimes made with next-higher available plate or pipe size while still respecting specified inside diameters.

Applications and markets of pipe fittings

Fittings are used wherever liquids, gases, chemicals and other fluids are created, processed, transported, or used.

Range of industries is very wide, as shown below:

  • Energy related. 
    Oil and gas industries, including upstream (exploration and production), midstream (transportation by ships, pipeline, rail, trucks; storage and wholesale) and downstream (refining into fuels or chemicals; marketing and distribution). Power plants using fossil or nuclear fuels. Geothermal energy for harnessing heat from the earth.
  • Food and beverage production. 
    From basic ingredients to elaborate desserts. From milk, to juices and other beverages. Cold chain to keep produce fresh, drinks and frozen foods at a set temperature. Desalination plants to transform seawater into drinking water for arid areas and various tropical islands.
  • Pharmaceuticals and biotech production. 
    Medicines and vaccines that treat illnesses and help restore bodies and minds to their top conditions.
  • Semiconductor manufacturing: 
    Microchips that go into all electronics, including smartphones, tablets, computers, television sets, telecom networks …
  • Pulp and paper production. 
    Newsprint, glossy paper, cardboard boxes, books, writing paper
  • Production of construction materials and plastics. From roofing materials, to glassmaking for windows, to copper wiring for transporting electricity, and various plastics throughout houses and office buildings.

How to get high quality pipe fittings?

Testing for pipe fittings

The most common non distructive tests (NDT) for pipe fittings:

  • Positive material identification (PMI): identification of the chemical composition of the metal used to manufacture the fitting. Uses PMI sensors, including X-ray fluorescence or optical emission spectrometry. This test is frequently executed for high value materials, from duplex steel onwards.
  • Penetrating liquids: this is a low-cost test to detect cracks or abnormal porosity on the surface of the fittings, and is executed by applying a special liquid to its surface.
  • Ferrite content: this test aims to measure the ferrite content for duplex, super duplex and stainless steel materials to make sure the metal is able to achieve the yield strength, fracture toughness and corrosion resistance it is meant to reach. Ferrite content is measured in weld seams by magnetic induction.
  • Hydrostatic test / hydro testing (pressure testing): the fitting gets filled with a test liquid (example water) and a pressure is applied to check if any pressure loss occurs (which would indicate manufacturing defects)
  • Magnetic particles: by means of a magnetic field, possible surface discontinuities or weakness can be identified
  • Macrography: 2 / 3 D pictures of items visible to naked eye.
  • Micrography: pictures at the microscope to see the microgranular structure of the metal and other details not visible at the naked eye
  • Pneumatic pressure: the fitting gets filled with pressurized air; measurements are taken to see if there is pressure loss due to any defects.
  • Radiography: X-rays / gamma rays to detect imperfections leading to possible quality defects

Out of the above tests, the pressure testing is one of the most commonly specified, especially for mission critical fittings in the pipeline.

Source: China Pipe Fittings Manufacturer – Yaang Pipe Industry (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@steeljrv.com

Please notice that you might be interested in the other technical articles we’ve published:

References:

  1. https://www.yaang.com

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