Blind Flange Dimensions: ASME B16.5

A blind flange is a type of flange that is used to close the end of a pipe, valve, or pressure vessel. Unlike regular flanges that are designed to connect pipes or fittings, blind flanges have a solid, flat plate without any openings. This makes them effective for sealing the end of a pipe, preventing the flow of fluid or gas.

Blind flanges are typically used in situations where the end of a pipeline needs to be closed off temporarily or permanently. They serve various purposes in industrial applications, including isolating sections of a piping system during maintenance or repairs. By attaching a blind flange, workers can safely work on a specific part of the pipeline without affecting the rest of the system.

Moreover, blind flanges are crucial for pressure testing and inspections. When conducting tests to assess the strength and integrity of a pipeline, engineers use blind flanges to seal off one end, allowing them to pressurize the system and evaluate its performance

This page will cover key dimensions for ASME B16.5 Lap Joint Flanges From 1/2 NPS to 24 NPS with Pressure rating classes 150, 300, 400, 600, 900, 1500, & 2500.

Please click on blow link for more information about:

ASME B16.5 Dimensional Tolerances & Welding Bevel Standards
ASME B16.5 Bolt & Stud Dimensions
ASME B16.47 A/B Large Diameter Flange Dimension from 26 NPS to 60 NPS

Blind Flange Dimensions — Blind Flange CL150

Blind Flange Class 150: ASME B16.5

wdt_ID	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D
1	½	3.50	0.38	1.38	4-0.62	2.38
2	¾	3.88	0.44	1.69	4-0.62	2.75
3	1	4.25	0.50	2.00	4-0.62	3.12
4	1¼	4.62	0.56	2.50	4-0.62	3.50
5	1½	5.00	0.62	2.88	4-0.62	3.88
6	2	6.00	0.69	3.62	4-0.75	4.75
7	2½	7.00	0.81	4.12	4-0.75	5.50
8	3	7.50	0.88	5.00	4-0.75	6.00
9	3½	8.50	0.88	5.50	8-0.75	7.00
10	4	9.00	0.88	6.19	8-0.75	7.50
11	5	10.00	0.88	7.31	8-0.88	8.50
12	6	11.00	0.94	8.50	8-0.88	9.50
13	8	13.50	1.06	10.62	8-0.88	11.75
14	10	16.00	1.12	12.75	12-1.00	14.25
15	12	19.00	1.19	15.00	12-1.00	17.00
16	14	21.00	1.31	16.25	12-1.12	18.75
17	16	23.50	1.38	18.50	16-1.12	21.25
18	18	25.00	1.50	21.00	16-1.25	22.75
19	20	27.50	1.62	23.00	20-1.25	25.00
20	22	29.50	1.75	25.25	20-1.38	27.25
21	24	32.00	1.81	27.25	20-1.38	29.50
	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D

Blind Flange Class 300: ASME B16.5

wdt_ID	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D
1	½	3.75	0.50	1.38	4-0.63	2.62
2	¾	4.62	0.56	1.69	4-0.75	3.25
3	1	4.88	0.62	2.00	4-0.75	3.50
4	1¼	5.25	0.69	2.50	4-0.75	3.88
5	1½	6.12	0.75	2.88	4-0.88	4.50
6	2	6.50	0.81	3.62	8-0.75	5.00
7	2½	7.50	0.94	4.12	8-0.88	5.88
8	3	8.25	1.06	5.00	8-0.88	6.62
9	3½	9.00	1.12	5.50	8-0.88	7.25
10	4	10.00	1.19	6.19	8-0.88	7.88
11	5	11.00	1.31	7.31	8-0.88	9.25
12	6	12.50	1.38	8.50	12-0.88	10.62
13	8	15.00	1.56	10.62	12-1.00	13.00
14	10	17.50	1.81	12.75	16-1.12	15.25
15	12	20.50	1.94	15.00	16-1.25	17.75
16	14	23.00	2.06	16.25	20-1.25	20.25
17	16	25.50	2.19	18.50	20-1.38	22.50
18	18	28.00	2.31	21.00	24-1.38	24.75
19	20	30.50	2.44	23.00	24-1.38	27.00
20	22	33.00	2.57	25.25	24-1.63	29.25
21	24	36.00	2.69	27.25	24-1.63	32.00
	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D

Blind Flange Class 400: ASME B16.5

wdt_ID	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D
1	½	3.75	0.56	1.38	4-0.63	2.62
2	¾	4.62	0.62	1.69	4-0.75	3.25
3	1	4.88	0.69	2.00	4- 75	3.50
4	1¼	5.25	0.81	2.50	4-0.75	3.88
5	1½	6.12	0.88	2.88	4-0.88	4.50
6	2	6.50	1.00	3.62	8-0.75	5.00
7	2½	7.50	1.12	4.12	8-0.88	5.88
8	3	8.25	1.25	5.00	8-0.88	6.62
9	3½	9.00	1.38	5.50	8-1.00	7.25
10	4	10.00	1.38	6.19	8-1.00	7.88
11	5	11.00	1.50	7.31	8-1.00	9.25
12	6	12.50	1.62	8.50	12-1.00	10.62
13	8	15.00	1.88	10.62	12-1.12	13.00
14	10	17.50	2.12	12.75	16-1.25	15.25
15	12	20.50	2.25	15.00	16-1.38	17.75
16	14	23.00	2.38	16.25	20-1.38	20.25
17	16	25.50	2.50	18.50	20-1.50	22.50
18	18	28.00	2.62	21.00	24-1.50	24.75
19	20	30.50	2.75	23.00	24-1.62	27.00
20	22	33.00	2.88	25.25	24-1.75	29.25
21	24	36.00	3.00	27.25	24-1.88	32.00
	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D

Blind Flange Class 600: ASME B16.5

wdt_ID	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D
1	½	3.75	0.56	1.38	4-0.63	2.62
2	¾	4.62	0.62	1.69	4-0.75	3.25
3	1	4.88	0.69	2.00	4-0.75	3.50
4	1¼	5.25	0.81	2.50	4-0.75	3.88
5	1½	6.12	0.88	2.88	4-0.88	4.50
6	2	6.50	1.00	3.62	8-0.75	5.00
7	2½	7.50	1.12	4.12	8-0.88	5.88
8	3	8.25	1.25	5.00	8-0.88	6.62
9	3½	9.00	1.38	5.50	8-1.00	7.25
10	4	10.75	1.50	6.19	8-1.00	8.50
11	5	13.00	1.75	7.31	8-1.12	10.50
12	6	14.00	1.88	8.50	12-1.12	11.50
13	8	16.50	2.19	10.62	12-1.25	13.75
14	10	20.00	2.50	12.75	16-1.38	17.00
15	12	22.00	2.62	15.00	20-1.38	19.25
16	14	23.75	2.75	16.25	20-1.50	20.75
17	16	27.00	3.00	18.50	20-1.63	23.75
18	18	29.25	3.25	21.00	20-1.75	25.75
19	20	32.00	3.50	23.00	24-1.75	28.50
20	22	34.25	3.75	25.25	24-1.75	30.63
21	24	37.00	4.00	27.25	24-2.00	33.00
	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D

Blind Flange Class 900: ASME B16.5

wdt_ID	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D
1	½	4.75	0.88	1.38	4-0.88	3.25
2	¾	5.12	1.00	1.69	4-0.88	3.50
3	1	5.88	1.12	2.00	4-1.00	4.00
4	1¼	6.25	1.12	2.50	4-1.00	4.38
5	1½	7.00	1.25	2.88	4-1.12	4.88
6	2	8.50	1.50	3.63	8-1.00	6.50
7	2½	9.62	1.62	4.13	8-1.12	7.50
8	3	9.50	1.50	5.00	8-1.00	7.50
9	4	11.50	1.75	6.19	8-1.25	9.25
10	5	13.75	2.00	7.31	8-1.38	11.00
11	6	15.00	2.19	8.50	12-1.25	12.50
12	8	18.50	2.50	10.63	12-1.50	15.50
13	10	21.50	2.75	12.75	16-1.50	18.50
14	12	24.00	3.12	15.00	20-1.50	21.00
15	14	25.25	3.38	16.25	20-1.63	22.00
16	16	27.75	3.50	18.50	20-1.75	24.25
17	18	31.00	4.00	21.00	20-2.00	27.00
18	20	33.75	4.25	23.00	20-2.13	29.50
19	24	41.00	5.50	27.25	20-2.63	35.50
	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D

Blind Flange Class 1500: ASME B16.5

wdt_ID	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D
1	½	4.75	0.88	1.38	4-0.88	3.25
2	¾	5.12	1.00	1.69	4-0.88	3.50
3	1	5.88	1.12	2.00	4-1.00	4.00
4	1¼	6.25	1.12	2.50	4-1.00	4.38
5	1½	7.00	1.25	2.88	4-1.12	4.88
6	2	8.50	1.50	3.63	8-1.00	6.50
7	2½	9.62	1.62	4.13	8-1.12	7.50
8	3	10.50	1.88	5.00	8-1.25	8.00
9	4	12.25	2.12	6.19	8-1.38	9.50
10	5	14.75	2.88	7.31	8-1.63	11.50
11	6	15.50	3.25	8.50	12-1.50	12.50
12	8	19.00	3.62	10.63	12-1.75	15.50
13	10	23.00	4.25	12.75	12-2.00	19.00
14	12	26.50	4.88	15.00	16-2.12	22.50
15	14	29.50	5.25	16.25	16-2.38	25.00
16	16	32.50	5.75	18.50	16-2.63	27.75
17	18	36.00	6.38	21.00	16-2.88	30.50
18	20	38.75	7.00	23.00	16-3.12	32.75
19	24	46.00	8.00	27.25	16-3.63	39.00
	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D

Blind Flange Class 2500: ASME B16.5

wdt_ID	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D
1	½	5.25	1.19	1.38	4-0.88	3.50
2	¾	5.50	1.25	1.69	4-0.88	3.75
3	1	6.25	1.38	2.00	4-1.00	4.25
4	1¼	7.25	1.50	2.50	4-1.12	5.13
5	1½	8.00	1.75	2.88	4-1.25	5.75
6	2	9.25	2.00	3.63	8-1.12	6.75
7	2½	10.50	2.25	4.13	8-1.25	7.75
8	3	12.00	2.62	5.00	8-1.38	9.00
9	4	14.00	3.00	6.19	8-1.63	10.75
10	5	16.50	3.62	7.31	8-1.88	12.75
11	6	19.00	4.25	8.50	8-2.12	14.50
12	8	21.75	5.00	10.63	12-2.12	17.25
13	10	26.50	6.50	12.75	12-2.63	21.25
14	12	30.00	7.25	15.00	12-2.88	24.38
	Nom. Pipe Size	O	T	R	# - Bolt Hole	B.C.D