Blind Flange

A Blind flange is round plate which has all of the relevant boltholes but no center hole, and because of this feature this flange is used to close off the ends of a piping systems and pressure vessel openings. It also permits easy access to the interior of a line or vessel once it has been sealed and must be reopened.

From the standpoint of internal pressure and bolt loading, blind flanges, particularly in the larger sizes, are the most highly stressed flange types.

However, most of these stresses are bending types near the center, and since there is no standard inside diameter, these flanges are suitable for higher pressure temperature applications.

Blind Flanges are commonly used in petrochemical, pipe engineering, public services & water works.

Flange Type	Slip-On; Welding Neck, Socket Welding, Blind, Thread, Lap-joint; Long Welding Neck; Orifice; All flanges in Raised Face, Flat face and RTJ;
Material	ASTM A105; A350 LF2; A694 F42, F46, F52, F56, A182 F12/F22/F5/F9/ F91; A182 F304/F304L/F316/F316L, etc.
Size	1/2”~60”, as the clients’ requests;
Pressure	Class: 150 300 400 600 900 1500 2500; PN6,PN10,PN16,PN25,PN40;5K,10K,16K,20K,30K
Standard	ASME B16.5, ASME B16.47, MSS SP43, EN1092，DIN, JIS;

Class 150 lb

Pipe		Flange Data		Raised Face	Drilling Data			Unit Weight
Nominal Pipe Size		A	C	G	H	I	J
	Outside Diameter	Overall Diameter	Flange Thickness min	Face Diameter	Number of  Holes	Bolt Hole Diameter	Diameter of Circle of Holes	kg/ piece
	in mm	in mm	in mm	in mm		in mm	in mm
1/2	0.840 21.30	3.500 88.90	0.440 11.20	1.380 35.10	4	0.620 15.70	2.380 60.45	0.42
3/4	1.050 26.70	3.880 98.60	0.500 12.70	1.690 42.90	4	0.620 15.70	2.750 69.85	0.61
1	1.315 33.40	4.250 108.0	0.560 14.20	2.000 50.80	4	0.620 15.70	3.120 79.25	0.86
1 1/4	1.660 42.20	4.620 117.3	0.620 15.70	2.500 63.50	4	0.620 15.70	3.500 88.90	1.17
1 1/2	1.900 48.30	5.000 127.0	0.690 17.50	2.880 73.15	4	0.620 15.70	3.880 98.60	1.53
2	2.375 60.30	6.000 152.4	0.750 19.10	3.620 91.90	4	0.750 19.10	4.750 120.7	2.42
2 1/2	2.875 73.00	7.000 177.8	0.880 22.40	4.120 104.6	4	0.750 19.10	5.500 139.7	3.94
3	3.500 88.90	7.500 190.5	0.940 23.90	5.000 127.0	4	0.750 19.10	6.000 152.4	4.93
31/2	4.000 101.6	8.500 215.9	0.940 23.90	5.500 139.7	8	0.750 19.10	7.000 177.8	6.17
4	4.500 114.3	9.000 228.6	0.940 23.90	6.190 157.2	8	0.750 19.10	7.500 190.5	7
5	5.563 141.3	10.00 254.0	0.940 23.90	7.310 185.7	8	0.880 22.40	8.500 215.9	8.63
6	6.625 168.3	11.00 279.4	1.000 25.40	8.500 215.9	8	0.880 22.40	9.500 241.3	11.3
8	8.625 219.1	13.50 342.9	1.120 28.40	10.62 269.7	8	0.880 22.40	298.5 11.75	19.6
10	10.75 273.0	16.00 406.4	1.190 30.20	12.75 323.9	12	1.000 25.40	14.25 362.0	28.8
12	12.75 323.8	19.00 482.6	1.250 31.75	15.00 381.0	12	1.000 25.40	17.00 431.8	43.2
14	14.00 355.6	21.00 533.4	1.380 35.10	16.25 412.8	12	1.120 28.40	18.75 476.3	58.1
16	16.00 406.4	23.50 596.9	1.440 36.60	18.50 469.9	16	1.120 28.40	21.25 539.8	76
18	18.00 457.2	25.00 635.0	1.560 39.60	21.00 533.4	16	1.250 31.75	22.75 577.9	93.7
20	20.00 508.0	27.50 698.5	1.690 42.90	23.00 584.2	20	1.250 31.75	25.00 635.0	122
24	24.00 609.6	32.00 812.8	1.880 47.80	27.25 692.2	20	1.380 35.10	29.50 749.3	185

Class 300 lb

Pipe		Flange Data		Raised Face	Drilling Data			Unit Weight
Nominal Pipe Size		A	C	G	H	I	J
	Outside Diameter	Overall Diameter	Flange Thickness min	Face Diameter	Number of  Holes	Bolt Hole Diameter	Diameter of Circle of Holes	kg/ piece
	in mm	in mm	in mm	in mm		in mm	in mm
1/2	0.840 21.30	3.750 95.20	0.560 14.20	1.380 35.10	4	0.620 15.70	2.620 66.55	0.64
3/4	1.050 26.70	4.620 117.3	0.620 15.70	1.690 42.90	4	0.750 19.00	3.250 82.50	1.11
1	1.315 33.40	4.880 123.9	0.690 17.50	2.000 50.80	4	0.750 19.00	3.500 88.90	1.39
1 1/4	1.660 42.20	5.250 133.3	0.750 19.00	2.500 63.50	4	0.750 19.00	3.880 98.50	1.79
1 1/2	1.900 48.30	6.120 155.4	0.810 20.60	2.880 73.15	4	0.880 22.3	4.500 114.3	2.66
2	2.375 60.30	6.500 165.1	0.880 22.30	3.620 91.90	8	0.750 19.10	5.000 127.0	3.18
2 1/2	2.875 73.00	7.500 190.5	1.000 25.40	4.120 104.6	8	0.880 22.30	5.880 1.493	4.85
3	3.500 88.90	8.250 209.5	1.120 28.40	5.000 127.0	8	0.880 22.30	6.620 168.1	6.81
31/2	4.000 101.6	9.000 228.6	1.190 30.20	5.500 139.7	8	0.880 22.30	7.250 184.1	8.71
4	4.500 114.3	10.00 254.0	1.250 31.70	6.190 157.2	8	0.880 22.30	7.800 200.1	11.5
5	5.563 141.3	11.00 279.4	1.380 35.00	7.310 185.7	8	0.880 22.30	9.250 234.9	15.6
6	6.625 168.3	12.50 317.5	1.440 36.50	8.500 215.9	12	0.880 22.30	10.62 269.7	20.9
8	8.625 219.1	15.00 381.0	1.620 41.10	10.62 269.7	12	1.000 25.40	13.00 330.2	34.3
10	10.75 273.0	17.50 444.5	1.880 47.70	12.75 323.9	16	1.120 28.40	15.25 387.3	53.3
12	12.75 323.8	20.50 520.7	2.000 50.80	15.00 381.0	16	1.250 31.70	17.75 450.8	78.8
14	14.00 355.6	23.00 584.2	2.120 53.80	16.25 412.8	20	1.250 31.70	20.25 514.3	105
16	16.00 406.4	25.50 647.7	2.250 57.15	18.50 469.9	20	1.380 35.00	22.50 571.5	137
18	18.00 457.2	28.00 711.2	2.380 60.45	21.00 533.4	24	1.380 35.00	24.75 628.6	175
20	20.00 508.0	30.50 774.7	2.500 63.50	23.00 584.2	24	1.380 35.00	27.00 685.8	221
24	24.00 609.6	36.00 914.4	2.750 69.85	27.25 692.2	24	1.620 41.10	32.00 812.8	339

Notes
- Weights are based on manufacturer’s data and are approximate.
- Flat face flanges may be provided at full thickness, C, or with raised face removed (the latter is nonstandard).


Class 400 lb

Pipe		Flange Data		Raised Face	Drilling Data			Unit Weight
Nominal Pipe Size		A	C	G	H	I	J
	Outside Diameter	Overall Diameter	Flange Thickness min	Face Diameter	Number of  Holes	Bolt Hole Diameter	Diameter of Circle of Holes	kg/ piece
	in mm	in mm	in mm	in mm		in mm	in mm
1/2	0.840 21.30	3.750 95.20	0.560 14.20	1.380 35.10	4	0.620 15.70	2.620 66.55	0.76
3/4	1.050 26.70	4.620 117.3	0.620 15.70	1.690 42.90	4	0.750 19.10	3.250 82.60	1.28
1	1.315 33.40	4.880 123.9	0.690 17.50	2.000 50.80	4	0.750 19.10	3.500 88.90	1.6
1 1/4	1.660 42.20	5.250 133.3	0.810 20.60	2.500 63.50	4	0.750 19.10	3.880 98.60	2.23
1 1/2	1.900 48.30	6.120 155.4	0.880 22.30	2.880 73.15	4	0.880 22.40	4.500 114.3	3.25
2	2.375 60.30	6.500 165.1	1.000 25.40	3.620 91.90	8	0.750 19.10	5.000 127.0	4.15
2 1/2	2.875 73.00	7.500 190.5	1.120 28.40	4.120 104.6	8	0.880 22.40	5.880 149.4	6.13
3	3.500 88.90	8.250 209.5	1.250 31.70	5.000 127.0	8	0.880 22.40	6.620 168.1	8.44
31/2	4.000 101.6	9.000 228.6	1.380 35.00	5.500 139.7	8	1.000 25.40	7.250 184.2	11
4	4.500 114.3	10.00 254.0	1.380 35.10	6.190 157.2	8	1.000 25.40	7.880 200.2	13.7
5	5.563 141.3	11.00 279.4	1.500 38.10	7.310 185.7	8	1.000 25.40	9.250 235.0	18.5
6	6.625 168.3	12.50 317.5	1.620 41.10	8.500 215.9	12	1.000 25.40	10.62 269.7	25.5
8	8.625 219.1	15.00 381.0	1.880 47.80	10.62 269.7	12	1.120 28.40	13.00 330.2	42.6
10	10.75 273.0	17.50 444.5	2.120 53.80	12.75 323.9	16	1.250 31.75	15.25 387.4	64.5
12	12.75 323.8	20.50 520.7	2.250 57.15	15.00 381.0	16	1.380 35.10	17.75 450.9	94.3
14	14.00 355.6	23.00 584.2	2.380 60.45	16.25 412.8	20	1.380 35.10	20.25 514.4	124
16	16.00 406.4	25.50 647.7	2.500 63.50	18.50 469.9	20	1.500 38.10	22.50 571.5	162
18	18.00 457.2	28.00 711.2	2.620 66.55	21.00 533.4	24	1.500 38.10	24.75 628.7	205
20	20.00 508.0	30.50 774.7	2.750 69.85	23.00 584.2	24	1.620 41.10	27.00 685.8	254
24	24.00 609.6	36.00 914.4	3.000 76.20	27.25 692.2	24	1.880 47.80	32.00 812.8	386

Class 600 lb

Pipe		Flange Data		Raised Face	Drilling Data			Unit Weight
Nominal Pipe Size		A	C	G	H	I	J
	Outside Diameter	Overall Diameter	Flange Thickness min	Face Diameter	Number of  Holes	Bolt Hole Diameter	Diameter of Circle of Holes	kg/ piece
	in mm	in mm	in mm	in mm		in mm	in mm
1/2	0.840 21.30	3.750 95.20	0.560 14.20	1.380 35.10	4	0.620 15.70	2.620 66.55	0.76
3/4	1.050 26.70	4.620 117.3	0.620 15.70	1.690 42.90	4	0.750 19.10	3.250 82.60	1.28
1	1.315 33.40	4.880 123.9	0.690 17.50	2.000 50.80	4	0.750 19.10	3.500 88.90	1.6
1 1/4	1.660 42.20	5.250 133.3	0.810 20.60	2.500 63.50	4	0.750 19.10	3.880 98.60	2.23
1 1/2	1.900 48.30	6.120 155.4	0.880 22.30	2.880 73.15	4	0.880 22.40	4.500 114.3	3.25
2	2.375 60.30	6.500 165.1	1.000 25.40	3.620 91.90	8	0.750 19.10	5.000 127.0	4.15
2 1/2	2.875 73.00	7.500 190.5	1.120 28.40	4.120 104.6	8	0.880 22.40	5.880 149.4	6.13
3	3.500 88.90	8.250 209.5	1.250 31.70	5.000 127.0	8	0.880 22.40	6.620 168.1	8.44
31/2	4.000 101.6	9.000 228.6	1.380 35.00	5.500 139.7	8	1.000 25.40	7.250 184.2	11
4	4.500 114.3	10.75 273.1	1.500 38.10	6.190 157.2	8	1.000 25.40	8.500 215.9	17.3
5	5.563 141.3	13.00 330.2	1.750 44.50	7.310 185.7	8	1.120 28.40	10.50 266.7	29.4
6	6.625 168.3	14.00 355.6	1.880 47.80	8.500 215.9	12	1.120 28.40	292.1 11.50	36.1
8	8.625 219.1	16.50 419.1	2.190 55.60	10.62 269.7	12	1.250 31.75	13.75 349.3	58.9
10	10.75 273.0	20.00 508.0	2.500 63.50	12.75 323.9	16	1.380 35.10	17.00 431.8	97.5
12	12.75 323.8	22.00 558.8	2.620 66.55	15.00 381.0	20	1.380 35.10	19.25 489.0	124
14	14.00 355.6	23.75 603.3	2.750 69.85	16.25 412.8	20	1.500 38.10	20.75 527.1	151
16	16.00 406.4	27.00 685.8	3.000 76.20	18.50 469.9	20	1.620 41.10	23.75 603.3	214
18	18.00 457.2	29.25 743.0	3.250 82.60	21.00 533.4	20	1.750 44.50	25.75 654.1	272
20	20.00 508.0	32.00 812.8	3.500 88.90	23.00 584.2	24	1.750 44.50	28.50 723.9	349
24	24.00 609.6	37.00 939.8	4.000 101.6	27.25 692.2	24	2.000 50.80	33.00 838.2	533

Class 900 lb

Pipe		Flange Data		Raised Face	Drilling Data			Unit Weight
Nominal Pipe Size		A	C	G	H	I	J
	Outside Diameter	Overall Diameter	Flange Thickness min	Face Diameter	Number of  Holes	Bolt Hole Diameter	Diameter of Circle of Holes	kg/ piece
	in mm	in mm	in mm	in mm		in mm	in mm
1/2	0.840 21.30	4.750 120.6	0.880 22.30	1.380 35.10	4	0.880 22.30	3.250 82.50	1.77
3/4	1.050 26.70	5.120 130.0	1.000 25.40	1.690 42.90	4	0.880 22.30	3.500 88.90	2.42
1	1.315 33.40	5.880 149.3	1.120 28.40	2.000 50.80	4	1.000 25.40	4.000 101.6	3.57
1 1/4	1.660 42.20	6.250 158.7	1.120 28.40	2.500 63.50	4	1.000 25.40	4.380 111.2	4.15
1 1/2	1.900 48.30	7.000 177.8	1.250 31.70	2.880 73.15	4	1.120 28.40	4.880 123.9	5.75
2	2.375 60.30	8.500 215.9	1.500 38.10	3.620 91.90	8	1.000 25.40	6.500 165.1	10.1
2 1/2	2.875 73.00	9.620 244.3	1.620 41.10	4.120 104.6	8	1.120 28.40	7.500 190.5	14
3	3.500 88.90	9.500 241.3	1.500 38.10	5.000 127.0	8	1.000 25.40	7.500 190.5	13.1
4	4.500 114.3	11.50 292.1	1.750 44.50	6.190 157.2	8	1.250 31.70	9.250 234.9	26.9
5	5.563 141.3	13.75 349.2	2.000 50.80	7.310 185.7	8	1.380 35.00	279.4 11.00	36.5
6	6.625 168.3	15.00 381.0	2.190 55.60	8.500 215.9	12	1.250 31.70	12.50 317.0	47.4
8	8.625 219.1	18.50 469.9	2.500 63.50	10.62 269.7	12	1.500 38.10	15.50 393.7	82.5
10	10.75 273.0	21.50 546.1	2.750 69.85	12.75 323.9	16	1.500 38.10	18.50 469.9	122
12	12.75 323.8	24.00 609.6	3.120 79.25	15.00 381.0	20	1.500 38.10	21.00 533.4	173
14	14.00 355.6	25.25 641.3	3.380 85.80	16.25 412.8	20	1.620 41.10	22.00 558.8	206
16	16.00 406.4	27.75 704.8	3.500 88.90	18.50 469.9	20	1.750 44.40	24.25 615.9	259
18	18.00 457.2	31.00 787.4	4.000 101.6	21.00 533.4	20	2.000 50.80	27.00 685.8	367
20	20.00 508.0	33.75 857.2	4.250 107.9	23.00 584.2	20	2.120 53.80	29.50 749.3	463
24	24.00 609.6	41.00 1041.4	5.500 139.7	27.25 692.2	20	2.620 66.55	35.50 901.7	876

Class 1500 lb

Pipe		Flange Data		Raised Face	Drilling Data			Unit Weight
Nominal Pipe Size		A	C	G	H	I	J
	Outside Diameter	Overall Diameter	Flange Thickness min	Face Diameter	Number of  Holes	Bolt Hole Diameter	Diameter of Circle of Holes	kg/ piece
	in mm	in mm	in mm	in mm		in mm	in mm
1/2	0.840 21.30	4.750 120.6	0.880 22.30	1.380 35.10	4	0.880 22.30	3.250 82.50	1.77
3/4	1.050 26.70	5.120 130.0	1.000 25.40	1.690 42.90	4	0.880 22.30	3.500 88.90	2.42
1	1.315 33.40	5.880 149.3	1.120 28.40	2.000 50.80	4	1.000 25.40	4.000 101.6	3.57
1 1/4	1.660 42.20	6.250 158.7	1.120 28.40	2.500 63.50	4	1.000 25.40	4.380 111.2	4.15
1 1/2	1.900 48.30	7.000 177.8	1.250 31.70	2.880 73.15	4	1.120 28.40	4.880 123.9	5.75
2	2.375 60.30	8.500 215.9	1.500 38.10	3.620 91.90	8	1.000 25.40	6.500 165.1	10.1
2 1/2	2.875 73.00	9.620 244.3	1.620 41.10	4.120 104.6	8	1.120 28.40	7.500 190.5	14
3	3.500 88.90	10.50 266.7	1.880 47.70	5.000 127.0	8	1.250 31.70	8.000 203.2	19.1
4	4.500 114.3	12.25 311.1	2.120 53.80	6.190 157.2	8	1.380 35.00	9.500 241.3	29.9
5	5.563 141.3	14.75 374.6	2.880 73.15	7.310 185.7	8	1.620 41.10	292.1 11.50	58.4
6	6.625 168.3	15.50 393.7	3.250 82.50	8.500 215.9	12	1.500 38.10	12.50 317.5	71.8
8	8.625 219.1	19.00 482.6	3.620 91.90	10.62 269.7	12	1.750 44.40	15.50 393.7	122
10	10.75 273.0	23.00 584.2	4.250 107.9	12.75 323.9	12	2.000 50.80	19.00 482.6	210
12	12.75 323.8	26.50 673.1	4.880 123.9	15.00 381.0	16	2.120 53.8	22.50 571.5	316
14	14.00 355.6	29.50 749.3	5.250 133.3	16.25 412.8	16	2.380 60.45	25.00 635.0	420
16	16.00 406.4	32.50 825.5	5.750 146.0	18.50 469.9	16	2.620 66.55	27.75 704.8	558
18	18.00 457.2	36.00 914.4	6.380 162.0	21.00 533.4	16	2.880 73.15	30.50 774.7	760
20	20.00 508.0	38.75 984.2	7.000 177.8	23.00 584.2	16	3.120 79.25	32.75 831.8	965
24	24.00 609.6	46.00 1168.4	8.000 203.2	27.25 692.2	16	3.620 91.90	39.00 990.6	1558

Class 2500 lb

Pipe		Flange Data		Raised Face	Drilling Data			Unit Weight
Nominal Pipe Size		A	C	G	H	I	J
	Outside Diameter	Overall Diameter	Flange Thickness min	Face Diameter	Number of  Holes	Bolt Hole Diameter	Diameter of Circle of Holes	kg/ piece
	in mm	in mm	in mm	in mm		in mm	in mm
1/2	0.840 21.30	5.250 133.4	1.190 30.20	1.380 35.10	4	0.880 22.40	3.500 88.90	2.99
3/4	1.050 26.70	5.500 139.7	1.250 31.70	1.690 42.90	4	0.880 22.40	3.750 95.30	3.5
1	1.315 33.40	6.250 158.8	1.380 35.10	2.000 50.80	4	1.000 25.40	4.250 108.0	4.96
1 1/4	1.660 42.20	7.250 184.2	1.500 38.10	2.500 63.50	4	1.120 28.40	5.120 130.0	7.35
1 1/2	1.900 48.30	8.000 203.2	1.750 44.50	2.880 73.15	4	1.250 31.75	5.750 146.1	10.4
2	2.375 60.30	9.250 235.0	2.000 50.80	3.620 91.90	8	1.120 28.40	6.750 171.5	15.6
2 1/2	2.875 73.00	10.50 266.7	2.250 57.15	4.120 104.6	8	1.250 31.75	7.750 196.9	22.6
3	3.500 88.90	12.00 304.8	2.620 66.55	5.000 127.0	8	1.380 35.10	9.000 228.6	34.8
4	4.500 114.3	14.00 355.6	3.000 76.20	6.190 157.2	8	1.620 41.10	10.75 273.1	53.9
5	5.563 141.3	16.50 419.1	3.620 91.90	7.310 185.7	8	1.888 47.88	12.75 323.9	90.8
6	6.625 168.3	19.00 482.6	4.250 108.0	8.500 215.9	8	2.120 53.80	14.50 368.3	141
8	8.625 219.1	21.75 552.5	5.000 127.0	10.62 269.7	12	2.120 53.80	17.25 438.2	214
10	10.75 273.0	26.50 673.1	6.500 165.1	12.75 323.9	12	2.620 66.55	21.25 539.8	411
12	12.75 323.8	30.00 762.0	7.250 184.2	15.00 381.0	12	2.880 73.15	24.38 619.3	592

Notes
- Weights are based on manufacturer’s data and are approximate.
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