ANSI / ASME B16.5 Class 400 Lap Joint Flange Dimensions

Lap Joint flanges are commonly used in low-pressure, non-corrosive medium systems, such as in industries like food processing, pharmaceuticals, and water treatment.

ANSI / ASME B16.5 Class 400 Lap Joint Flange

Class 400 Lap Joint Flange Dimensions in Inch/lbs

Class 400 Lap Joint Flange Dimensions in mm/kg

Class 400 Lap Joint Flange Dimensions in Inch/lbs

Class 400 Lap Joint Flange Dimensions in mm/kg

ANSI / ASME B16.5 Class 300 Lap Joint Flange is a type of flange that conforms to the ANSI/ASME B16.5 standard, designed for pipelines requiring a pressure rating of Class 400. It uses a “lap joint” design, where the flange is not directly welded to the pipe but is instead used with a Stub End that is welded to the pipe. The flange can rotate freely around the pipe, making alignment easier.

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FAQ

What materials are used for these flanges?

Common materials include:
Carbon steel
Stainless steel
Alloy steel
Other materials depending on the application (e.g., corrosion resistance or high-temperature needs).

Are there limitations to using Lap Joint Flanges?

They are not recommended for extremely high-pressure or high-vibration environments.
The Stub End must be welded to the pipe, which adds an extra step to the installation process.
Not ideal for systems requiring a fully welded connection.

Nominal Pipe Size	Outside Diameter (O)	Thickness (T)	Length Thru Hub (Y)	Hub Diameter (X)	Radius (r)	Bore (B)	Approximate Weight (lbs)	Bolt Circle (C)	Number of Holes	Diameter of Holes
1/2	3.75	0.56	1.38	0.88	0.13	0.90	2	2.63	4	0.63
3/4	4.63	0.63	1.69	1.00	0.13	1.11	3	3.25	4	0.75
1	4.88	0.69	2.00	1.06	0.13	1.38	4	3.50	4	0.75
1 1/4	5.25	0.81	2.50	1.13	0.19	1.72	5	3.88	4	0.75
1 1/2	6.13	0.88	2.88	1.25	0.25	1.97	7	4.50	4	0.88
2	6.50	1.00	3.63	1.44	0.31	2.46	9	5.00	8	0.75
2 1/2	7.50	1.13	4.13	1.63	0.31	2.97	12	5.88	8	0.88
3	8.25	1.25	5.00	1.81	0.38	3.60	15	6.63	8	0.88
3 1/2	9.00	1.38	5.50	1.94	0.38	4.10	20	7.25	8	1.00
4	10.00	1.38	2.00	5.75	0.44	4.60	25	7.88	8	1.00
5	11.00	1.50	2.13	7.00	0.44	5.69	29	9.25	8	1.00
6	12.50	1.63	2.25	8.13	0.50	6.75	42	10.63	12	1.00
8	15.00	1.88	2.69	10.25	0.50	8.75	64	13.00	12	1.13
10	17.50	2.13	4.00	12.63	0.50	10.92	110	15.25	16	1.25
12	20.50	2.25	4.25	14.75	0.50	12.92	150	17.75	16	1.38
14	23.00	2.38	4.63	16.75	0.50	14.18	205	20.25	20	1.38
16	25.50	2.50	5.00	19.00	0.50	16.19	260	22.50	20	1.50
18	28.00	2.63	5.38	21.00	0.50	18.20	315	24.75	24	1.50
20	30.50	2.75	5.75	23.13	0.50	20.25	385	27.00	24	1.63
22	33.00	2.88	6.00	25.25	0.50	22.25	455	29.25	24	1.75
24	36.00	3.00	6.25	27.63	0.50	24.25	570	32.00	24	1.88

Nominal Pipe Size	Outside Diameter (O)	Thickness (T)	Length Thru Hub (Y)	Hub Diameter (X)	Radius (r)	Bore (B)	Approximate Weight (lbs)	Bolt Circle (C)	Number of Holes	Diameter of Holes
1/2	95.25	14.22	35.05	22.35	3.30	22.86	0.91	66.80	4	16.00
3/4	117.60	16.00	42.93	25.40	3.30	28.19	1.36	82.55	4	19.05
1	123.95	17.53	50.80	26.92	3.30	35.05	1.81	88.90	4	19.05
1 1/4	133.35	20.57	63.50	28.70	4.83	43.69	2.27	98.55	4	19.05
1 1/2	155.70	22.35	73.15	31.75	6.35	50.04	3.18	114.30	4	22.35
2	165.10	25.40	92.20	36.58	7.87	62.48	4.08	127.00	8	19.05
2 1/2	190.50	28.70	104.90	41.40	7.87	75.44	5.44	149.35	8	22.35
3	209.55	31.75	127.00	45.97	9.65	91.44	6.80	168.40	8	22.35
3 1/2	228.60	35.05	139.70	49.28	9.65	104.14	9.07	184.15	8	25.40
4	254.00	35.05	50.80	146.05	11.18	116.84	11.34	200.15	8	25.40
5	279.40	38.10	54.10	177.80	11.18	144.53	13.15	234.95	8	25.40
6	317.50	41.40	57.15	206.50	12.70	171.45	19.05	270.00	12	25.40
8	381.00	47.75	68.33	260.35	12.70	222.25	29.03	330.20	12	28.70
10	444.50	54.10	101.60	320.80	12.70	277.37	49.89	387.35	16	31.75
12	520.70	57.15	107.95	374.65	12.70	328.17	68.04	450.85	16	35.05
14	584.20	60.45	117.60	425.45	12.70	360.17	92.99	514.35	20	35.05
16	647.70	63.50	127.00	482.60	12.70	411.23	117.93	571.50	20	38.10
18	711.20	66.80	136.65	533.40	12.70	462.28	142.88	628.65	24	38.10
20	774.70	69.85	146.05	587.50	12.70	514.35	174.63	685.80	24	41.40
22	838.20	73.15	152.40	641.35	12.70	565.15	206.38	742.95	24	44.45
24	914.40	76.20	158.75	701.80	12.70	615.95	258.55	812.80	24	47.75