Long Neck Welding (abbreviated LWN) flanges are similar to a standard Welding Neck flange, but the “Neck” is considerably longer. This type is often used as a nozzle for a barrel or column. In addition, there are the type LWN Heavy Barrel (HB) and the Equal LWN Barrel (E); they have a different shape and a thicker “Wall”.

ASME B16.5 Long Weld Neck Flange Class 150 LBS Dimensions
NPS
O
Tf
X
B
Y
W
BH
Holes
1/2″
88.9
9.7
30.2
12.7
228.6
60.5
15.9
4
3/4″
98.6
11.2
38.1
19.1
228.6
69.9
15.9
4
1″
108.0
12.7
49.3
25.4
228.6
79.2
15.9
4
1-1/4″
117.5
14.2
58.7
31.8
228.6
88.9
15.9
4
1-1/2″
127.0
15.7
65.0
38.1
228.6
98.6
15.9
4
2″
152.4
17.5
77.7
50.8
228.6
120.7
19.1
4
2-1/2″
177.8
20.6
90.4
63.5
228.6
139.7
19.1
4
3″
190.5
22.4
108.0
76.2
228.6
152.4
19.1
4
3-1/2″
215.9
22.4
122.2
88.9
228.6
177.8
19.1
8
4″
228.6
22.4
134.9
101.6
228.6
190.5
19.1
8
5″
254.0
22.4
163.6
127.0
304.8
215.9
22.2
8
6″
279.4
23.9
192.0
152.4
304.8
241.3
22.2
8
8″
342.9
26.9
246.1
203.2
304.8
298.5
22.2
8
10″
406.4
28.4
304.8
254.0
304.8
362.0
25.4
12
12″
482.6
30.2
365.3
304.8
304.8
431.8
25.4
12
14″
533.4
33.3
400.1
355.6
304.8
476.3
28.6
12
16″
596.9
35.1
457.2
406.4
304.8
539.8
28.6
16
18″
635.0
38.1
505.0
457.2
304.8
577.9
31.8
16
20″
698.5
41.1
558.8
508.0
304.8
635.0
31.8
20
24″
812.8
46.0
663.4
609.6
304.8
749.3
34.9
20

 

ASME B16.5 Long Weld Neck Flange Class 300 LBS Dimensions
NPS
O
Tf
X
B
Y
W
BH
Holes
1/2″
95.3
12.7
38.1
12.7
228.6
66.5
15.9
4
3/4″
117.3
14.2
47.8
19.1
228.6
82.6
19.1
4
1″
124.0
15.7
53.8
25.4
228.6
88.9
19.1
4
1-1/4″
133.4
17.5
63.5
31.8
228.6
98.6
19.1
4
1-1/2″
155.4
19.1
69.9
38.1
228.6
114.3
22.2
4
2″
165.1
20.6
84.1
50.8
228.6
127.0
19.1
8
2-1/2″
190.5
23.9
100.1
63.5
228.6
149.4
22.2
8
3″
209.6
26.9
117.3
76.2
228.6
168.1
22.2
8
3-1/2″
228.6
28.4
133.4
88.9
228.6
184.2
22.2
8
4″
254.0
30.2
146.1
101.6
228.6
200.2
22.2
8
5″
279.4
33.3
177.8
127.0
304.8
235.0
22.2
8
6″
317.5
35.1
206.2
152.4
304.8
269.7
22.2
12
8″
381.0
39.6
260.4
203.2
304.8
330.2
25.4
12
10″
444.5
46.0
320.5
254.0
304.8
387.4
28.6
16
12″
520.7
49.3
374.7
304.8
304.8
450.9
31.8
16
14″
584.2
52.3
425.5
355.6
304.8
514.4
31.8
20
16″
647.7
55.6
482.6
406.4
304.8
571.5
34.9
20
18″
711.2
58.7
533.4
457.2
304.8
628.7
34.9
24
20″
774.7
62.0
587.2
508.0
304.8
685.8
34.9
24
24″
914.4
68.3
701.5
609.6
304.8
812.8
41.3
24

 

ASME B16.5 Long Weld Neck Flange Class 400 LBS Dimensions
NPS
O
Tf
X
B
Y
W
BH
Holes
1/2″
95.3
14.2
38.1
12.7
228.6
66.5
15.9
4
3/4″
117.3
15.7
47.8
19.1
228.6
82.6
19.1
4
1″
124
17.5
53.8
25.4
228.6
88.9
19.1
4
1-1/4″
133.4
20.6
63.5
31.8
228.6
98.6
19.1
4
1-1/2″
155.4
22.4
69.9
38.1
228.6
114.3
22.2
4
2″
165.1
25.4
84.1
50.8
228.6
127
19.1
8
2-1/2″
190.5
28.4
100.1
63.5
228.6
149.4
22.2
8
3″
209.6
31.8
117.3
76.2
228.6
168.1
22.2
8
3-1/2″
228.6
35.1
133.4
88.9
228.6
184.2
25.4
8
4″
254
35.1
146.1
101.6
228.6
200.2
25.4
8
5″
279.4
38.1
177.8
127
304.8
235
25.4
8
6″
317.5
41.1
206.2
152.4
304.8
269.7
25.4
12
8″
381
47.8
260.4
203.2
304.8
330.2
28.6
12
10″
444.5
53.8
320.5
254
304.8
387.4
31.8
16
12″
520.7
57.2
374.7
304.8
304.8
450.9
34.9
16
14″
584.2
60.5
425.5
355.6
304.8
514.4
34.9
20
16″
647.7
63.5
482.6
406.4
304.8
571.5
38.1
20
18″
711.2
66.5
533.4
457.2
304.8
628.7
38.1
24
20″
774.7
69.9
587.2
508
304.8
685.8
41.3
24
24″
914.4
76.2
701.5
609.6
304.8
812.8
47.6
24

 

ASME B16.5 Long Weld Neck Flange Class 600 LBS Dimensions

NPS
O
Tf
X
B
Y
W
BH
Holes
1/2″
95.3
14.2
38.1
12.7
228.6
66.5
15.9
4
3/4″
117.3
15.7
47.8
19.1
228.6
82.6
19.1
4
1″
124
17.5
53.8
25.4
228.6
88.9
19.1
4
1-1/4″
133.4
20.6
63.5
31.8
228.6
98.6
19.1
4
1-1/2″
155.4
22.4
69.9
38.1
228.6
114.3
22.2
4
2″
165.1
25.4
84.1
50.8
228.6
127
19.1
8
2-1/2″
190.5
28.4
100.1
63.5
228.6
149.4
22.2
8
3″
209.6
31.8
117.3
76.2
228.6
168.1
22.2
8
3-1/2″
228.6
35.1
133.4
88.9
228.6
184.2
25.4
8
4″
273.1
38.1
152.4
101.6
228.6
215.9
25.4
8
5″
330.2
44.5
189
127
304.8
266.7
28.6
8
6″
355.6
47.8
222.3
152.4
304.8
292.1
28.6
12
8″
419.1
55.6
273.1
203.2
304.8
349.3
31.8
12
10″
508
63.5
342.9
254
304.8
431.8
34.9
16
12″
558.8
66.5
400.1
304.8
304.8
489
34.9
20
14″
603.3
69.9
431.8
355.6
304.8
527.1
38.1
20
16″
685.8
76.2
495.3
406.4
304.8
603.3
41.3
20
18″
743
82.6
546.1
457.2
304.8
654.1
44.5
20
20″
812.8
88.9
609.6
508
304.8
723.9
44.5
24
24″
939.8
101.6
717.6
609.6
304.8
838.2
50.8
24

 

ASME B16.5 Long Weld Neck Flange Class 900 LBS Dimensions
NPS
O
Tf
X
B
Y
W
BH
Holes
1/2″
120.7
22.4
38.1
12.7
228.6
82.6
22.2
4
3/4″
130
25.4
44.5
19.1
228.6
88.9
22.2
4
1″
149.4
28.4
52.3
25.4
228.6
101.6
25.4
4
1-1/4″
158.8
28.4
63.5
31.8
228.6
111.3
25.4
4
1-1/2″
177.8
31.8
69.9
38.1
228.6
124
28.6
4
2″
215.9
38.1
104.6
50.8
228.6
165.1
25.4
8
2-1/2″
244.3
41.1
124
63.5
228.6
190.5
28.6
8
3″
241.3
38.1
127
76.2
228.6
190.5
25.4
8
3-1/2″
4″
292.1
44.5
158.8
101.6
228.6
235
31.8
8
5″
349.3
50.8
190.5
127
304.8
279.4
34.9
8
6″
381
55.6
235
152.4
304.8
317.5
31.8
12
8″
469.9
63.5
298.5
203.2
304.8
393.7
38.1
12
10″
546.1
69.9
368.3
254
304.8
469.9
38.1
16
12″
609.6
79.2
419.1
304.8
304.8
533.4
38.1
20
14″
641.4
85.9
450.9
355.6
304.8
558.8
41.3
20
16″
704.9
88.9
508
406.4
304.8
616
44.5
20
18″
787.4
101.6
565.2
457.2
304.8
685.8
50.8
20
20″
857.3
108
622.3
508
304.8
749.3
54
20
24″
1041.4
139.7
749.3
609.6
304.8
901.7
66.7
20

 

ASME B16.5 Long Weld Neck Flange Class 1500 LBS Dimensions

 

NPS
O
Tf
X
B
Y
W
BH
Holes
1/2″
120.7
22.4
38.1
12.7
228.6
82.6
22.2
4
3/4″
130.0
25.4
44.5
19.1
228.6
88.9
22.2
4
1″
149.4
28.4
52.3
25.4
228.6
101.6
25.4
4
1-1/4″
158.8
28.4
63.5
31.8
228.6
111.3
25.4
4
1-1/2″
177.8
31.8
69.9
38.1
228.6
124.0
28.6
4
2″
215.9
38.1
104.6
50.8
228.6
165.1
25.4
8
2-1/2″
244.3
41.1
124.0
63.5
228.6
190.5
28.6
8
3″
266.7
47.8
133.4
76.2
228.6
203.2
31.8
8
3-1/2″
4″
311.2
53.8
162.1
101.6
228.6
241.3
34.9
8
5″
374.7
73.2
196.9
127.0
304.8
292.1
41.3
8
6″
393.7
82.6
228.6
152.4
304.8
317.5
38.1
12
8″
482.6
91.9
292.1
203.2
304.8
393.7
44.5
12
10″
584.2
108.0
368.3
254.0
304.8
482.6
50.8
12
12″
673.1
124.0
450.9
304.8
304.8
571.5
54.0
16
14″
749.3
133.4
495.3
355.6
304.8
635.0
60.3
16
16″
825.5
146.1
552.5
406.4
304.8
704.9
66.7
16
18″
914.4
162.1
596.9
457.2
304.8
774.7
73.0
16
20″
984.3
177.8
641.4
508.0
304.8
831.9
79.4
16
24″
1168.4
203.2
762.0
609.6
304.8
990.6
92.1
16

 

ASME B16.5 Long Weld Neck Flange Class 2500 LBS Dimensions
NPS
O
Tf
X
B
Y
W
BH
Holes
1/2″
133.4
30.2
42.9
12.7
228.6
88.9
22.2
4
3/4″
139.7
31.8
50.8
19.1
228.6
95.3
22.2
4
1″
158.8
35.1
57.2
25.4
228.6
108
25.4
4
1-1/4″
184.2
38.1
73.2
31.8
228.6
130
28.6
4
1-1/2″
203.2
44.5
79.2
38.1
228.6
146.1
31.8
4
2″
235
50.8
95.3
50.8
228.6
171.5
28.6
8
2-1/2″
266.7
57.2
114.3
63.5
228.6
196.9
31.8
8
3″
304.8
66.5
133.4
76.2
228.6
228.6
34.9
8
3-1/2″
4″
355.6
76.2
165.1
101.6
228.6
273.1
41.3
8
5″
419.1
91.9
203.2
127
304.8
323.9
47.6
8
6″
482.6
108
235
152.4
304.8
368.3
54
8
8″
552.5
127
304.8
203.2
304.8
438.2
54
12
10″
673.1
165.1
374.7
254
304.8
539.8
66.7
12
12″
762
184.2
441.5
304.8
304.8
619.3
73
12