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Definition of threaded fittings acc to ASME B16.11

Definition of threaded fittings acc to ASME B16.11

AUTHOR : _ _ Date : 3/7/2013 3:06:05 AM
THREADED FITTINGS GENERAL

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 4 or smaller.
The dimensional standards for taper pipe threads are given in ASME B1.20.1.
This document gives all required dimensions including number of threads per inch, pitch diameter, and normal engagement lengths for all pipe diameters.

1.
Threaded piping is commonly used in low-cost, noncritical applications such as domestic water, fire protection, and industrial cooling water systems.
2. Threaded fittings are normally made of cast gray or malleable iron, cast brass or bronze, or forged alloy and carbon steel, standless steel.
3.
They are available in three pressure ratings: 2000lbs, 3000lbs and 6000lbs.

All fittings on this page are described, are provided with NPT thread, according to 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.
NPT has a tapered male and female thread which seals with Teflon tape or jointing compound.

DIMENSIONS OF AMERICAN TAPER PIPE THREAD, WITH SEALANT COMPOUND
Dia Nominal
NPT
Major Diameter
mm
Tapping
Drill Size mm
TPI Pitch
mm
1/16" 7.895 6.00 27 0.941
1/8" 10.242 8.25 27 0.941
1/4" 13.616 10.70 18 1.411
3/8" 17.055 14.10 18 1.411
1/2" 21.223 17.40 14 1.814
3/4" 26.568 22.60 14 1.814
1" 33.228 28.50 11.5 2.209
1 1/4" 41.985 37.00 11.5 2.209
1 1/2" 48.054 43.50 11.5 2.209
2" 60.092 55.00 11.5 2.209
2 1/2" 72.699 65.50 8 3.175
3" 88.608 81.50 8 3.175
3 1/2" 101.316 94.30 8 3.175
4" 113.973 107.00 8 3.175
5" 141.300 134.384 8 3.175
6" 168.275 161.191 8 3.175
8" 219.075 211.673 8 3.175
10" 273.050 265.311 8 3.175
12" 323.850 315.793 8 3.175


TYPES OF THREADED FITTINGS BY CLASS AND SIZE
 
Description Class Designation
2000 3000 6000
Tees, Crosses, Coupling
Half-Coupling, Cap
1/2 - 4 1/2 - 2 1/2 - 2
1/2 - 4 1/2 - 2 1/2 - 2
1/2 - 4 1/2 - 2 1/2 - 2
Pipe Wall SCH 80 and XS SCH 160 XXS
 

Plugs and
Bushings  are not identified. They may be used up through Class 6000 NPS


ADVANTAGES AND DISADVANTAGES OFTHREADED FITTINGS

Advantages
1.
Installation productivity is moderately high, and specialized installation skill requirements are not extensive.
2.
Leakage integrity is good for low-pressure, low-temperature installations where vibration is not encountered.

Disadvantages
1.
Rapid temperature changes may lead to leaks due to differential thermal expansion between the pipe and fittings.
2.
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.
3.
Socket welds are not acceptable in piping systems involving nuclear or radioactive service or corrosive service with solutions which promote stress corrosion cracking or concentration cell action. Generally require butt welds in all pipe sizes with complete weld penetration to the inside of the piping.
4.
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.



• 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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