Lap Joint Flange

It is Flange with radius at the bore.

Lap Joint flanges are similar to slip-on flanges. The only difference is that it has a curved radius at the bore and face to accommodate a lap joint stub end. They may be used at all pressures and are available in a full size range. These lap joint flanges slip over the pipe, and are not welded. They are otherwise fastened to it. Here the bolting pressure is transferred to the gasket by the pressure of the flange against the back of the pipe lap.

Lap Joint flanges are used on piping fitted with lapped pipe or with lap joint stub ends the combined initial cost of the two items being approximately one-third higher than that of comparable welding neck flanges. Their pressure-holding ability is little, if any, better than that of slip-on flanges and the fatigue life of the assembly is only one-tenth that of welding neck flanges. The lap joint flange with the stub end assembly are normally used in systems requiring frequent dismantling for inspection and cleaning and where the ability to swivel flanges and to align bolt holes materially eases the erection of large diameter or unusually stiff piping. These flanges are also used in applications where there is a need to facilitate bolt alignment. Their use at points where severe bending stress occurs should be avoided.

These Flanges are available in the following range.

Stainless Steel: ASTM A182 F304, F304L, F304H, F316, F316L, F316Ti, F310, F310S, F321, F321H, F317, F347, F347H, F904L.
Duplex Stainless Steel: UNS S31803, UNS S32750
Carbon Steel: ASTM A105,
Alloy Steel: ASTM A182 F1, F11, F22, F5, F9, F91
Nickel Alloys: Monel 400 & 500, Inconel 600 & 625, Incoloy 800, 825, Hastelloy C22, C276
Copper Alloys: Copper, Brass & Gunmetal
Size: 1/8" NB TO 48"NB.
Class: 150#, 300#, 400#, 600#, 900#, 1500#, 2500#

Dimensional Standard
ANSI: ANSI B16.5, ANSI B16.47, MSS SP44, ANSI B16.36, ANSI B16.48
DIN: DIN 2527, DIN 2566, DIN 2573, DIN 2576, DIN 2641, DIN 2642, DIN 2655, DIN 2656, DIN 2627, DIN 2628, DIN 2629, DIN 2631, DIN 2632, DIN 2633, DIN 2634, DIN 2635, DIN 2636, DIN 2637, DIN 2638, DIN 2673
BS: BS 4504, BS4504, BS1560, BS10

DIMENSIONS of CLASS 150 FLANGES AS PER ANSI B 16.5
NB		A	D	B	E	K	H	L	No. of Holes
½”	15	30.2	88.9	11.1	22.9	60.3	15.9	15.9	4
¾”	20	38.1	98.4	12.7	28.2	69.8	15.9	15.9	4
1”	25	49.2	107.9	14.3	35.0	79.4	17.5	15.9	4
1 ¼”	32	58.7	117.5	15.9	43.7	88.9	20.6	15.9	4
1 ½”	40	65.1	127.0	17.5	50.0	98.4	22.2	15.9	4
2”	50	77.8	152.4	19.0	62.5	120.6	25.4	19.0	4
2 ½”	65	90.5	177.8	22.2	75.4	139.7	28.6	19.0	4
3”	80	107.9	190.5	23.8	91.4	152.4	30.2	19.0	4
4”	100	134.9	230.0	23.8	116.8	190.5	33.3	19.0	8
5”	125	163.5	254.0	23.8	144.5	215.9	36.5	22.2	8
6”	150	192.1	279.4	25.4	171.4	241.3	39.7	22.2	8
8”	200	246.1	342.9	28.6	222.2	298.4	44.4	22.2	8
10”	250	304.8	406.4	30.2	277.4	361.9	49.2	25.4	12
12”	300	365.1	482.6	31.8	328.2	431.8	55.6	25.4	12
14”	350	400.0	533.4	34.9	360.2	476.2	79.4	28.6	12
16”	400	457.2	596.9	36.5	411.2	539.7	87.3	28.6	16
18”	450	504.8	635.0	39.7	462.3	577.8	96.8	31.7	16
20”	500	558.8	698.5	42.9	514.3	635.0	103.2	31.7	20
24”	600	663.6	812.8	47.6	615.9	749.3	111.1	34.9	20

DIMENSIONS of CLASS 300 FLANGES AS PER ANSI B 16.5
NB		A	D	B	E	K	H	L	No. of Holes
½”	15	38.1	95.2	14.3	22.9	66.7	22.2	15.9	4
¾”	20	47.6	117.5	15.9	28.2	82.5	25.4	19.0	4
1”	25	54.0	123.8	17.5	35.0	88.9	27.0	19.0	4
1 ¼”	32	63.5	133.3	19.0	43.7	98.4	27.0	19.0	4
1 ½”	40	69.8	155.6	20.6	50.0	114.3	30.2	22.2	4
2”	50	84.1	165.1	22.2	62.5	127.0	33.3	19.0	8
2 ½”	65	100.0	190.5	25.4	75.4	149.2	38.1	22.2	8
3”	80	117.5	209.5	28.6	91.4	168.3	42.9	22.2	8
4”	100	146.0	254.0	31.8	116.8	200.0	47.6	22.2	8
5”	125	177.8	279.4	34.9	144.5	234.9	50.8	22.2	8
6”	150	206.4	317.5	36.5	171.4	269.9	52.4	22.2	12
8”	200	260.3	381.0	41.3	222.2	330.2	61.9	25.4	12
10”	250	320.7	444.5	47.6	277.4	387.3	95.2	28.6	16
12”	300	374.6	520.7	50.8	328.2	450.8	101.6	31.7	16
14”	350	425.4	584.2	54.0	360.2	514.3	111.1	31.7	20
16”	400	482.6	647.7	57.2	411.2	571.5	120.6	34.9	20
18”	450	533.4	711.2	60.3	462.3	628.5	130.2	34.9	24
20”	500	587.4	774.7	63.5	514.3	685.8	139.7	34.9	24
24”	600	701.7	914.4	69.8	615.9	812.8	152.4	41.3	24

DIMENSIONS of CLASS 600 FLANGES AS PER ANSI B 16.5
NB		A	D	B	E	K	H	L	No. of Holes
½”	15	38.1	95.2	14.3	22.9	66.7	22.3	15.9	4
¾”	20	47.6	117.5	15.9	28.2	82.5	25.4	19.0	4
1”	25	54.0	123.8	17.5	35.0	88.9	26.9	19.0	4
1 ¼”	32	63.5	133.3	20.6	43.7	98.4	28.4	19.0	4
1 ½”	40	69.8	155.6	22.2	50.0	114.3	31.7	22.2	4
2”	50	84.1	165.1	25.4	62.5	127.0	36.5	19.0	8
2 ½”	65	100.0	190.5	28.6	75.4	149.2	41.1	22.2	8
3”	80	117.5	209.5	31.8	91.4	168.3	45.9	22.2	8
4”	100	152.4	273.0	38.1	116.8	215.9	53.8	25.4	8
5”	125	188.9	330.2	44.4	144.5	266.7	60.4	28.6	8
6”	150	222.2	355.6	47.6	171.4	292.1	66.5	28.6	12
8”	200	273.0	419.1	55.6	222.2	349.2	76.2	31.7	12
10”	250	342.9	508.0	63.5	277.4	431.8	111.2	34.9	16
12”	300	400.0	558.8	66.7	328.2	488.9	117.3	34.9	20
14”	350	431.8	603.2	69.9	360.2	527.0	127.0	38.1	20
16”	400	495.3	685.8	75.2	411.2	603.2	139.7	41.3	20
18”	450	546.0	742.9	82.6	462.3	654.0	152.4	44.4	20
20”	500	609.6	812.8	88.9	514.3	723.9	165.1	44.4	24
24”	600	717.6	939.8	101.6	615.9	838.2	184.1	50.8	24

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All dimensions are in millimeters unless otherwise indicated.

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