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99
HIGH PRESSURE FITTINGS [6]
Specifications
American National Standard Taper Pipe Threads, NPT
Nominal Pipe
Outside
Dia. Of
Pipe,
Threads
per Inch,
Pitch
of Thread,
Pitch
Diameter
at
Beginning
of External
Thread,
Handtight Engagement
Effective Thread, External
Length,a
L1
Dia.,b
E1
Length,c
L2
Dia.,
E2
Size
D
n
p
E0
Inch
Inch
1/16
0.3125
27
0.03704
0.27118
0.160
0.28118
0.2611
0.28750
1/8
0.405
27
0.03704
0.36351
0.1615
0.37360
0.2639
0.38000
1/4
0.540
18
0.05556
0.47739
0.2278
0.49163
0.4018
0.50250
3/8
0.675
18
0.05556
0.61201
0.240
0.62701
0.4078
0.63750
1/2
0.840
14
0.07143
0.75843
0.320
0.77843
0.5337
0.79179
3/4
1.050
14
0.07143
0.96768
0.339
0.98887
0.5457
1.00179
1
1.315
11.5
0.08696
1.21363
0.400
1.23863
0.6828
1.25630
1 1/4
1.660
11.5
0.08696
1.55713
0.420
1.58338
0.7068
1.60130
1 1/2
1.900
11.5
0.08696
1.79609
0.420
1.82234
0.7235
1.84130
2
2.375
11.5
0.08696
2.26902
0.436
2.29627
0.7565
2.31630
2 1/2
2.875
8
0.12500
2.71953
0.682
2.76216
1.1375
2.79062
3
3.500
8
0.12500
3.34062
0.766
3.38850
1.2000
3.41562
3 1/2
4.000
8
0.12500
3.83750
0.821
3.88881
1.2500
3.91562
4
4.500
8
0.12500
4.33438
0.844
4.38712
1.3600
4.41562
5
5.563
8
0.12500
5.39073
0.937
5.44929
1.4063
5.47862
6
6.625
8
0.12500
6.44609
0.958
6.50597
1.5125
6.54062
Angle between sides of thread is 60 degrees. Taper of thread, on diameter is 3 1/2 inch per foot.
Angle of taper with center line is 1˚47’.
The basic maximum thread height, h, of the truncated thread is 0.8 x pitch of thread. The crest and root are truncated a
minimum of 0.033 x pitch for all pitches. For maximum depth of truncation, see Table 2.
A Also length of thin ring gage and length from gaging notch to small end of plug gage.
B Also pitch diameter at gauging notch (handtight plane).
C Also length of plug gauge.
Imperfect Threads
due to Chamfer on
die
Taper of Thread 1
in 16 Measured on
Diameter
E3
E2
E5 E1
E0
D
L4
L2
V
L1
2p
L5
L3
Pressure Temperature Chart
PSI (°F)
nominal
pressure
ratings
Screwed and Socket welding fittings
-20 ~ 100° 150° 200° 250° 300° 350° 400° 450° 500° 550° 600° 650° 700° 750° 800° 850° 900° 950° 1000°
2000lb
2000 1970 1940 1915 1895 1875 1850 1810 1735 1640 1540 1430 1305 1180 1015 830 615 425 235
3000lb
3000 2955 2915 2875 2845 2810 2775 2715 2605 2460 2310 2150 1960 1775 1525 1250 925 640 355
6000lb
6000 5915 5830 5750 5690 5625 5550 5430 5210 4925 4620 4300 3920 3550 3050 2500 1855 1285 715
1,2 4,5,6,7,8,9,10,11,12,13,...23