Threaded Flange Dimensions & Weights (ASME B16.5)

Quick Reference

ASME B16.5 threaded flange dimensions (NPS 1/2” to 24”) for Classes 150-2500. NPT threads per ASME B1.20.1. Used where welding is prohibited (explosive environments) or for low-P/T utilities.

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Need a printable version? Download the ASME B16.5 Flange Dimensions Chart for all flange types and pressure classes.

ASME Threaded Flange Dimensions and Weights

The tables below show ASME B16.5 threaded flange dimensions including: inside diameter (ID), outside diameter (OD), bolt circle, raised face diameter, flange thickness, and bolt hole specifications.

Threaded Flange Sizes in Inches

Threaded Class 150

Threaded flange dimensions for Class 150 per ASME B16.5 (in inches). Includes OD, ID, bolt circle, raised face dimensions, and bolt hole specifications.

FLANGENPS	InsideDiameter	OutsideDiameter	Bolt Circle (BC)	Raised Face (R)	Raised Face (RF)	H	Raised Face Thickness (T)	T1	Flat Face Thickness (T2)	Bolt Hole (B)	No. of Bolt Holes
1/2″	0.93″	3.50″	2.38″	1.38″	.063″	1.19″	.62″	.38″	.56″	.62″	4
3/4″	1.14″	3.88″	2.75″	1.69″	.063″	1.50″	.62″	.44″	.56″	.62″	4
1″	1.41″	4.25″	3.12″	2.00″	.063″	1.94″	.69″	.50″	.63″	.62″	4
1-1/4″	1.75″	4.62″	3.50″	2.50″	.063″	2.31″	.81″	.56″	.75″	.62″	4
1-1/2″	1.99″	5.00″	3.88″	2.88″	.063″	2.56″	.88″	.62″	.82″	.62″	4
2″	2.50″	6.00″	4.75″	3.62″	.063″	3.06″	1.00″	.69″	.94″	.75″	4
2-1/2″	3.00″	7.00″	5.50″	4.12″	.063″	3.56″	1.12″	.82″	1.06″	.75″	4
3″	3.63″	7.50″	6.00″	5.00″	.063″	4.25″	1.19″	.88″	1.13″	.75″	4
3-1/2″	4.13″	8.50″	7.00″	5.50″	.063″	4.81″	1.25″	.88″	1.19″	.75″	8
4″	4.63″	9.00″	7.50″	6.19″	.063″	5.31″	1.31″	.88″	1.25″	.75″	8
5″	5.69″	10.00″	8.50″	7.31″	.063″	6.44″	1.44″	.88″	1.38″	.88″	8
6″	6.75″	11.00″	9.50″	8.50″	.063″	7.56″	1.56″	.94″	1.50″	.88″	8
8″	8.75″	13.50″	11.75″	10.62″	.063″	9.69″	1.75″	1.06″	1.69″	.88″	8
10″	10.88″	16.00″	14.25″	12.75″	.063″	12.00″	1.94″	1.13″	1.88″	1.00″	12
12″	12.94″	19.00″	17.00″	15.00″	.063″	14.38″	2.19″	1.19″	2.13″	1.00″	12
14″	14.19″	21.00″	18.75″	16.25″	.063″	15.75″	2.25″	1.32″	2.19″	1.12″	12
16″	16.19″	23.50″	21.25″	18.50″	.063″	18.00″	2.50″	1.38″	2.44″	1.12″	16
18″	18.19″	25.00″	22.75″	21.00″	.063″	19.88″	2.69″	1.50″	2.63″	1.25″	16
20″	20.19″	27.50″	25.00″	23.00″	.063″	22.00″	2.88″	1.63″	2.83″	1.25″	20
22″	22.19″	29.50″	27.25″	25.25″	.063″	24.25″	3.13″	1.75″	3.07″	1.38″	20
24″	24.19″	32.00″	29.50″	27.25″	.063″	26.12″	3.25″	1.82″	3.19″	1.38″	20

Threaded Class 300

Threaded flange dimensions class 300 in inches (ASME B16.5)

FLANGENPS	InsideDiameter	OutsideDiameter	Bolt Circle (BC)	Raised Face (R)	Raised Face (RF)	H	Raised Face Thickness (T)	T1	Flat Face Thickness (T2)	Bolt Hole (B)	No. of Bolt Holes
1/2″	0.93″	3.75″	2.62″	1.38″	.063″	1.50″	0.88″	0.50″	0.82″	0.62″	4
3/4″	1.14″	4.62″	3.25″	1.69″	.063″	1.88″	1.00″	.056″	0.94″	0.75″	4
1″	1.41″	4.88″	3.50″	2.00″	.063″	2.12″	1.06″	0.63″	1.00″	0.75″	4
1-1/4″	1.75″	5.25″	3.88″	2.50″	.063″	2.50″	1.06″	0.69″	1.00″	0.75″	4
1-1/2″	1.99″	6.12″	4.50″	2.88″	.063″	2.75″	1.19″	0.75″	1.13″	0.88″	4
2″	2.50″	6.50″	5.00″	3.62″	.063″	3.31″	1.31″	0.82″	1.25″	0.75″	8
2-1/2″	3.00″	7.50″	5.88″	4.12″	.063″	3.94″	1.50″	0.94″	1.44″	0.88″	8
3″	3.63″	8.25″	6.62″	5.00″	.063″	4.62″	1.69″	1.06″	1.63″	0.88″	8
3-1/2″	4.13″	9.00″	7.25″	5.50″	.063″	5.25″	1.75″	1.13″	1.69″	0.88″	8
4″	4.63″	10.00″	7.88″	6.19″	.063″	5.75″	1.88″	1.19″	1.82″	0.88″	8
5″	5.69″	11.00″	9.25″	7.31″	.063″	7.00″	2.00″	1.32″	1.94″	0.88″	8
6″	6.75″	12.50″	10.62″	8.50″	.063″	8.12″	2.06″	1.38″	2.00″	0.88″	12
8″	8.75″	15.00″	13.00″	10.62″	.063″	10.25″	2.44″	1.56″	2.38″	1.00″	12
10″	10.88″	17.50″	15.25″	12.75″	.063″	12.62″	2.62″	1.82″	2.56″	1.12″	16
12″	12.94″	20.50″	17.75″	15.00″	.063″	14.75″	2.88″	1.94″	2.82″	1.25″	16
14″	14.19″	23.00″	20.25″	16.25″	.063″	16.75″	3.00″	2.06″	2.94″	1.25″	20
16″	16.19″	25.50″	22.50″	18.50″	.063″	19.00″	3.25″	2.19″	3.19″	1.38″	20
18″	18.19″	28.00″	24.75″	21.00″	.063″	21.00″	3.50″	2.32″	3.44″	1.38″	24
20″	20.19″	30.50″	27.00″	23.00″	.063″	23.12″	3.75″	2.44″	3.69″	1.38″	24
22″	22.19″	33.00″	29.25″	25.25″	.063″	25.25″	4.00″	2.57″	3.94″	1.63″	24
24″	24.19″	36.00″	32.00″	27.25″	.063″	27.62″	4.19″	2.69″	4.13″	1.62″	24

Threaded Class 400

Threaded flange dimensions class 400 in inches (ASME B16.5)

FLANGENPS	InsideDiameter	OutsideDiameter	Bolt Circle (BC)	Raised Face (R)	Raised Face (RF)	H	Raised Face Thickness (T)	T1	Flat Face Thickness (T2)	Bolt Hole (B)	No. of Bolt Holes
1/2″	0.93″	3.75″	2.62″	0.12″	.250″	1.50″	1.13″	0.56″	0.88″	0.62″	4
3/4″	1.14″	4.62″	3.25″	0.12″	.250″	1.88″	1.25″	0.62″	1.00″	0.75″	4
1″	1.41″	4.88″	3.50″	0.12″	.250″	2.12″	1.31″	0.69″	1.06″	0.75″	4
1-1/4″	1.75″	5.25″	3.88″	0.19″	.250″	2.50″	1.37″	0.81″	1.12″	0.75″	4
1-1/2″	1.99″	6.12″	4.50″	0.25″	.250″	2.75″	1.50″	0.88″	1.25″	0.88″	4
2″	2.50″	6.50″	5.00″	0.31″	.250″	3.31″	1.69″	1.00″	1.44″	0.75″	8
2-1/2″	3.00″	7.50″	5.88″	0.31″	.250″	3.94″	1.87″	1.12″	1.62″	0.88″	8
3″	3.63″	8.25″	6.62″	0.38″	.250″	4.62″	2.06″	1.25″	1.81″	0.88″	8
3-1/2″	4.13″	9.00″	7.25″	0.38″	.250″	5.25″	2.19″	1.38″	1.94″	1.00″	8
4″	4.63″	10.00″	7.88″	0.44″	.250″	5.75″	2.25″	1.38″	2.00″	1.00″	8
5″	5.69″	11.00″	9.25″	0.44″	.250″	7.00″	2.37″	1.50″	2.12″	1.00″	8
6″	6.75″	12.50″	10.62″	0.50″	.250″	8.12″	2.50″	1.62″	2.25″	1.00″	12
8″	8.75″	15.00″	13.00″	0.50″	.250″	10.25″	2.94″	1.88″	2.69″	1.12″	12
10″	10.88″	17.50″	15.25″	0.50″	.250″	12.62″	3.13″	2.12″	2.88″	1.25″	16
12″	12.94″	20.50″	17.75″	0.50″	.250″	14.75″	3.37″	2.25″	3.12″	1.38″	16
14″	14.19″	23.00″	20.25″	0.50″	.250″	16.75″	3.56″	2.38″	3.31″	1.38″	20
16″	16.19″	25.50″	22.50″	0.50″	.250″	19.00″	3.94″	2.50″	3.69″	1.50″	20
18″	18.19″	28.00″	24.75″	0.50″	.250″	21.00″	4.13″	2.62″	3.88″	1.50″	24
20″	20.19″	30.50″	27.00″	0.50″	.250″	23.12″	4.25″	2.75″	4.00″	1.62″	24
22″	22.19″	33.00″	29.25″	0.50″	.250″	25.25″	4.50″	2.88″	4.25″	1.75″	24
24″	24.19″	36.00″	32.00″	0.50″	.250″	27.62″	4.75″	3.00″	4.50″	1.88″	24

Threaded Class 600

Threaded flange dimensions class 600 in inches (ASME B16.5)

FLANGENPS	InsideDiameter	OutsideDiameter	Bolt Circle (BC)	Raised Face (R)	Raised Face (RF)	H	Raised Face Thickness (T)	T1	Flat Face Thickness (T2)	Bolt Hole (B)	No. of Bolt Holes
1/2″	0.93″	3.75″	2.62″	1.38″	.250″	1.50″	1.13″	0.56″	0.88″	0.62″	4
3/4″	1.14″	4.62″	3.25″	1.69″	.250″	1.88″	1.25″	0.62″	1.00″	0.75″	4
1″	1.41″	4.88″	3.50″	2.00″	.250″	2.12″	1.31″	0.69″	1.06″	0.75″	4
1-1/4″	1.75″	5.25″	3.88″	2.50″	.250″	2.50″	1.37″	0.81″	1.12″	0.75″	4
1-1/2″	1.99″	6.12″	4.50″	2.88″	.250″	2.75″	1.50″	0.88″	1.25″	0.88″	4
2″	2.50″	6.50″	5.00″	3.62″	.250″	3.31″	1.69″	1.00″	1.44″	0.75″	8
2-1/2″	3.00″	7.50″	5.88″	4.12″	.250″	3.94″	1.87″	1.12″	1.62″	0.88″	8

Threaded Class 900

Threaded flange dimensions class 900 in inches (ASME B16.5)

FLANGENPS	InsideDiameter	OutsideDiameter	Bolt Circle (BC)	Raised Face (R)	Raised Face (RF)	H	Raised Face Thickness (T)	T1	Flat Face Thickness (T2)	Bolt Hole (B)	No. of Bolt Holes
1/2″	0.93″	4.75″	3.25″	1.38″	.250″	1.50″	1.50″	0.88″	1.25″	0.88″	4
3/4″	1.14″	5.13″	3.50″	1.69″	.250″	1.75″	1.63″	1.00″	1.38″	0.88″	4
1″	1.41″	5.88″	4.00″	2.00″	.250″	2.06″	1.88″	1.13″	1.63″	1.00″	4
1-1/4″	1.75″	6.25″	4.38″	2.50″	.250″	2.50″	1.88″	1.13″	1.63″	1.00″	4
1-1/2″	1.99″	7.00″	4.88″	2.88″	.250″	2.75″	2.00″	1.25″	1.75″	1.13″	4
2″	2.50″	8.50″	6.50″	3.63″	.250″	4.13″	2.50″	1.50″	2.25″	1.00″	8
2-1/2″	3.00″	9.63″	7.50″	4.13″	.250″	4.88″	2.75″	1.63″	2.50″	1.13″	8
3″	3.63″	9.50″	7.50″	5.00″	.250″	5.00″	2.38″	1.50″	2.13″	1.00″	8
4″	4.63″	11.50″	9.25″	6.19″	.250″	6.25″	3.00″	1.75″	2.75″	1.25″	8
5″	5.69″	13.75″	11.00″	7.31″	.250″	7.50″	3.38″	3.00″	3.13″	1.38″	8
6″	6.75″	15.00″	12.50″	8.50″	.250″	9.25″	3.63″	2.19″	3.38″	1.25″	12
8″	8.75″	18.50″	15.50″	10.63″	.250″	11.75″	4.25″	2.50″	4.00″	1.50″	12
10″	10.88″	21.50″	18.50″	12.75″	.250″	14.50″	4.50″	2.75″	4.25″	1.50″	16
12″	12.94″	24.00″	21.00″	15.00″	.250″	16.50″	4.88″	3.13″	4.63″	1.50″	20
14″	14.19″	25.25″	22.00″	16.25″	.250″	17.75″	5.38″	3.38″	5.13″	1.63″	20
16″	16.19″	27.75″	24.25″	18.50″	.250″	20.00″	5.50″	3.50″	5.25″	1.75″	20
18″	18.19″	31.00″	27.00″	21.00″	.250″	22.25″	6.25″	4.00″	6.00″	2.00″	20
20″	20.19″	33.75″	29.50″	23.00″	.250″	24.50″	6.50″	4.25″	6.25″	2.13″	20
24″	24.19″	41.00″	35.50″	27.25″	.250″	29.50″	8.25″	5.50″	8.00″	2.63″	20

Threaded Class 1500

Threaded flange dimensions class 1500 in inches (ASME B16.5)

FLANGENPS	InsideDiameter	OutsideDiameter	Bolt Circle (BC)	Raised Face (R)	Raised Face (RF)	H	Raised Face Thickness (T)	T1	Flat Face Thickness (T2)	Bolt Hole (B)	No. of Bolt Holes
1/2″	0.93″	4.75″	3.25″	1.38″	.250″	1.50″	1.50″	0.88″	1.25″	0.88″	4
3/4″	1.14″	5.13″	3.50″	1.69″	.250″	1.75″	1.63″	1.00″	1.38″	0.88″	4
1″	1.41″	5.88″	4.00″	2.00″	.250″	2.06″	1.88″	1.13″	1.63″	1.00″	4
1-1/4″	1.75″	6.25″	4.38″	2.50″	.250″	2.50″	1.88″	1.13″	1.63″	1.00″	4
1-1/2″	1.99″	7.00″	4.88″	2.88″	.250″	2.75″	2.00″	1.25″	1.75″	1.13″	4
2″	2.50″	8.50″	6.50″	3.63″	.250″	4.13″	2.50″	1.50″	2.25″	1.00″	8
2-1/2″	3.00″	9.63″	7.50″	4.13″	.250″	4.88″	2.75″	1.63″	2.50″	1.13″	8

Threaded Class 2500

Threaded flange dimensions class 2500 in inches (ASME B16.5)

FLANGENPS	InsideDiameter	OutsideDiameter	Bolt Circle (BC)	Raised Face (R)	Raised Face (RF)	H	Raised Face Thickness (T)	T1	Flat Face Thickness (T2)	Bolt Hole (B)	No. of Bolt Holes
1/2″	0.93″	5.25″	3.50″	1.38″	.250″	1.69″	1.81″	1.19″	1.56″	0.88″	4
3/4″	1.14″	5.50″	3.75″	1.69″	.250″	2.00″	1.94″	1.25″	1.69″	0.88″	4
1″	1.41″	6.25″	4.25″	2.00″	.250″	2.25″	2.13″	1.38″	1.88″	1.00″	4
1-1/4″	1.75″	7.25″	5.13″	2.50″	.250″	2.88″	2.31″	1.50″	2.06″	1.13″	4
1-1/2″	1.99″	8.00″	5.75″	2.88″	.250″	3.13″	2.63″	1.75″	2.38″	1.25″	4
2″	2.50″	9.25″	6.75″	3.63″	.250″	3.75″	3.00″	2.00″	2.75″	1.13″	8
2-1/2″	3.00″	10.50″	7.75″	4.13″	.250″	4.50″	3.38″	2.25″	3.13″	1.25″	8

Threaded Flange Sizes in Millimeters

Threaded Class 150

Threaded flange dimensions class 150 in millimeters (ASME B16.5)

Sizeinch	Dmm	Xmm	Gmm	tmm	T2mm	Qmm
1/2	89	30.2	35.1	11.2	15.7	15.7
3/4	99	38.1	42.9	12.7	15.7	15.7
1	108	49.3	50.8	14.2	17.5	17.5
1¼	117	58.7	63.5	15.7	20.6	20.6
1½	127	65.0	73.2	17.5	22.4	22.4
2	152	77.7	91.9	19.1	25.4	25.4
2½	178	90.4	104.6	22.4	28.4	28.4
3	191	108.0	127.0	23.9	30.2	30.2
3½	216	122.2	139.7	23.9	31.8	31.8
4	229	134.9	157.2	23.9	33.3	33.3
5	254	163.6	185.7	23.9	36.6	36.6
6	279	192.0	215.9	25.4	39.6	39.6
8	343	246.1	269.7	28.4	44.5	44.5
10	406	304.8	323.9	30.2	49.3	49.3
12	483	365.3	381.0	31.8	55.6	55.6
14	533	400.1	412.8	35.1	57.2	57.2
16	597	457.2	469.9	36.6	63.5	63.5
18	635	505.0	533.4	39.6	68.3	68.3
20	699	558.8	584.2	42.9	73.2	73.2
24	813	663.4	692.2	47.8	82.6	82.6

Size (inch)	Bolt Circle Dia. (mm)	Holes #	Holes Dia. (mm)	Bolt Dia. (inch)	Length FF Flange	Length RF Flange	Length RTJ Flange
1/2	60.5	4	15.7	1/2	50.8	57.2	–
3/4	69.9	4	15.7	1/2	50.8	63.5	–
1	79.2	4	15.7	1/2	57.2	63.5	76.2
1¼	88.9	4	15.7	1/2	57.2	69.9	82.6
1½	98.6	4	15.7	1/2	63.5	69.9	82.6
2	120.7	4	19.1	5/8	69.9	82.6	95.3
2½	139.7	4	19.1	5/8	76.2	88.9	101.6
3	152.4	4	19.1	5/8	76.2	88.9	101.6
3½	177.8	8	19.1	5/8	76.2	88.9	101.6
4	190.5	8	19.1	5/8	76.2	88.9	101.6
5	215.9	8	22.4	3/4	82.6	95.3	108.0
6	241.3	8	22.4	3/4	82.6	101.6	114.3
8	298.5	8	22.4	3/4	88.9	108.0	120.7
10	362.0	12	25.4	7/8	101.6	114.3	127.0
12	431.8	12	25.4	7/8	101.6	120.7	133.4
14	476.3	12	28.4	1	114.3	133.4	146.1
16	539.8	16	28.4	1	114.3	133.4	146.1
18	577.9	16	31.8	11/8	127.0	146.1	158.8
20	635.0	20	31.8	11/8	139.7	158.8	171.5
24	749.3	20	35.1	1¼	152.4	171.5	184.2

Threaded Class 300

Threaded flange dimensions class 300 in millimeters (ASME B16.5)

Sizeinch	Dmm	Xmm	Gmm	tmm	Bmm	T2mm	Qmm
1/2	95	38.1	35.1	14.2	23.6	22.4	15.7
3/4	117	47.8	42.9	15.7	29.0	25.4	15.7
1	124	53.8	50.8	17.5	35.8	26.9	17.5
1¼	133	63.5	63.5	19.1	44.5	26.9	20.6
1½	155	69.9	73.2	20.6	50.5	30.2	22.4
2	165	84.1	91.9	22.4	63.5	33.3	28.4
2½	191	100.1	104.6	25.4	76.2	38.1	31.8
3	210	117.3	127.0	28.4	92.2	42.9	31.8
3½	229	133.4	139.7	30.2	104.9	44.5	36.6
4	254	146.1	157.2	31.8	117.6	47.8	36.6
5	279	177.8	185.7	35.1	144.5	50.8	42.9
6	318	206.2	215.9	36.6	171.5	52.3	46.0
8	381	260.4	269.7	41.1	222.3	62.0	50.8
10	445	320.5	323.9	47.8	276.4	66.5	55.6
12	521	374.7	381.0	50.8	328.7	73.2	60.5
14	584	425.5	412.8	63.8	360.4	76.2	63.5
16	648	482.6	469.9	57.2	411.2	82.6	68.3
18	711	533.4	533.4	60.5	462.0	88.9	69.9
20	775	587.2	584.2	63.5	512.8	95.3	73.2
24	914	701.5	692.2	69.9	614.4	106.4	82.6

Size (inch)	Bolt Circle Dia. (mm)	Holes #	Holes Dia. (mm)	Bolt Dia. (inch)	Length FF Flange	Length RF Flange	Length RTJ Flange
1/2	66.5	4	15.7	1/2	57.2	63.5	76.2
3/4	82.6	4	19.1	5/8	63.5	76.2	88.9
1	88.9	4	19.1	5/8	63.5	76.2	88.9
1¼	98.6	4	19.1	5/8	69.9	82.6	95.3
1½	114.3	4	22.4	3/4	76.2	88.9	101.6
2	127.0	8	19.1	5/8	76.2	88.9	101.6
2½	149.4	8	22.4	3/4	82.6	101.6	114.3
3	168.1	8	22.4	3/4	88.9	108.0	120.7
3½	184.2	8	22.4	3/4	95.3	108.0	127.0
4	200.2	8	22.4	3/4	95.3	114.3	127.0
5	235.0	8	22.4	3/4	108.0	120.7	133.4
6	269.7	12	22.4	3/4	108.0	120.7	139.7
8	330.2	12	25.4	7/8	120.7	139.7	152.4
10	387.4	16	28.4	1	139.7	158.8	171.5
12	450.9	16	31.8	11/8	146.1	171.5	184.2
14	514.4	20	31.8	11/8	158.8	177.8	190.5
16	571.5	20	35.1	1¼	165.1	190.5	203.2
18	628.7	24	35.1	1¼	171.5	196.9	209.6
20	685.8	24	35.1	1¼	184.2	203.2	222.3
24	812.8	24	41.1	1½	203.2	228.6	254.0

Threaded Class 600

Threaded flange dimensions class 600 in millimeters (ASME B16.5)

Sizeinch	Dmm	Xmm	Gmm	tmm	B2mm	T2mm	Qmm
1/2	95	38.1	35.1	14.2	22.4	22.4	15.7
3/4	117	47.8	42.9	15.7	27.7	25.4	15.7
1	124	53.8	50.8	17.5	34.5	26.9	17.5
1¼	133	63.5	63.5	20.6	43.2	28.4	20.6
1½	155	69.9	73.2	22.4	49.5	31.8	22.4
2	165	84.1	91.9	25.4	62.0	36.6	28.4
2½	191	100.1	104.6	28.4	74.7	41.1	31.8
3	210	117.3	127.0	31.8	90.7	46.0	35.1
3½	229	133.4	139.7	35.1	103.4	49.3	39.6
4	273	152.4	157.2	38.1	116.1	53.8	41.1
5	330	189.0	185.7	44.5	143.8	60.5	47.8
6	356	222.3	215.9	47.8	170.7	66.5	50.8
8	419	273.1	269.7	55.6	221.5	76.2	57.2
10	508	342.9	323.9	63.5	276.4	85.9	65.0
12	559	400.1	381.0	66.5	327.2	91.9	69.9
14	603	431.8	412.8	69.9	359.2	93.7	73.2
16	686	495.3	469.9	76.2	410.5	106.4	77.7
18	743	546.1	533.4	82.6	461.8	117.3	79.2
20	813	609.6	584.2	88.9	513.1	127.0	82.6
24	940	717.6	692.2	101.6	616.0	139.7	91.9

Size (inch)	Bolt Circle Dia. (mm)	Holes #	Holes Dia. (mm)	Bolt Dia. (inch)	Length FF Flange	Length RF Flange	Length RTJ Flange
1/2	66.5	4	15.7	1/2	76.2	69.9	76.2
3/4	82.6	4	19.1	5/8	88.9	82.6	88.9
1	88.9	4	19.1	5/8	88.9	82.6	88.9
1¼	98.6	4	19.1	5/8	95.3	88.9	95.3
1½	114.3	4	22.4	3/4	108.0	101.6	108.0
2	127.0	8	19.1	5/8	108.0	101.6	108.0
2½	149.4	8	22.4	3/4	120.7	114.3	120.7
3	168.1	8	22.4	3/4	127.0	120.7	127.0
3½	184.2	8	25.4	7/8	139.7	133.4	139.7
4	215.9	8	25.4	7/8	146.1	139.7	146.1
5	266.7	8	28.4	1	165.1	158.8	165.1
6	292.1	12	28.4	1	171.5	165.1	171.5
8	349.3	12	31.8	11/8	190.5	184.2	196.9
10	431.8	16	35.1	1¼	215.9	209.6	215.9
12	489.0	20	35.1	1¼	222.3	215.9	222.3
14	527.1	20	38.1	13/8	235.0	228.6	235.0
16	603.3	20	41.1	1½	254.0	247.7	254.0
18	654.1	20	44.5	15/8	273.1	266.7	273.1
20	723.9	24	44.5	15/8	285.8	279.4	292.1
24	838.2	24	50.8	17/8	330.2	323.9	336.6

Threaded Class 900

Threaded flange dimensions class 900 in millimeters (ASME B16.5)

Sizeinch	Dmm	Xmm	Gmm	tmm	Bmm	T2mm	Qmm
1/2	121	38.1	35.1	22.4	23.6	31.8	22.4
3/4	130	44.5	42.9	25.4	29.0	35.1	25.4
1	149	52.3	50.8	28.4	35.8	41.1	28.4
1¼	159	63.5	63.5	28.4	44.5	41.1	30.2
1½	178	69.9	73.2	31.8	50.5	44.5	31.8
2	216	104.6	91.9	38.1	63.5	57.2	38.1
2½	244	124.0	104.6	41.1	76.2	63.5	47.8
3	241	127.0	127.0	38.1	92.2	53.8	41.1
4	292	158.8	157.2	44.5	117.6	69.9	47.8
5	349	190.5	185.7	50.8	144.5	79.2	53.8
6	381	235.0	215.9	55.6	171.5	85.9	57.2
8	470	298.5	269.7	63.5	222.3	101.6	63.5
10	546	368.3	323.9	69.9	276.4	108.0	71.4
12	610	419.1	381.0	79.2	328.7	117.3	76.2
14	641	450.9	412.8	85.9	360.4	130.0	82.6
16	705	508.0	469.9	88.9	411.2	133.4	85.9
18	787	565.2	533.4	101.6	462.0	152.4	88.9
20	857	622.3	584.2	108.0	512.8	158.8	91.9
24	1041	749.3	692.2	139.7	614.4	203.2	101.6

Size (inch)	Bolt Circle Dia. (mm)	Holes #	Holes Dia. (mm)	Bolt Dia. (inch)	Length FF Flange	Length RF Flange	Length RTJ Flange
1/2	82.6	4	22.4	3/4	108.0	101.6	108.0
3/4	88.9	4	22.4	3/4	114.3	108.0	114.3
1	101.6	4	25.4	7/8	127.0	120.7	127.0
1¼	111.3	4	25.4	7/8	127.0	120.7	127.0
1½	124.0	4	28.4	1	139.7	133.4	139.7
2	165.1	8	25.4	7/8	146.1	139.7	146.1
2½	190.5	8	28.4	1	158.8	152.4	158.8
3	190.5	8	25.4	7/8	146.1	139.7	146.1
4	235.0	8	31.8	11/8	171.5	165.1	171.5
5	279.4	8	35.1	1¼	190.5	184.2	190.5
6	317.5	12	31.8	11/8	190.5	184.2	196.9
8	393.7	12	38.1	13/8	222.3	215.9	222.3
10	469.9	16	38.1	13/8	235.0	228.6	235.0
12	533.4	20	38.1	13/8	254.0	247.7	254.0
14	558.8	20	41.1	1½	273.1	266.7	292.1
16	616.0	20	44.5	15/8	285.8	279.4	298.5
18	685.8	20	50.8	17/8	323.9	317.5	333.6
20	749.3	20	53.8	2	349.3	342.9	362.0
24	901.7	20	66.5	1½	438.2	431.8	457.2

Tolerance of Threaded Flanges

ASME B16.5 provides specific tolerances for threaded flanges to ensure they fit properly, function as intended, and maintain seal integrity under operating conditions. Threaded flanges, designed to connect pipes without welding, have internal threads that match the external threads of the pipe. Here are general tolerance values for key dimensions of threaded flanges according to ASME B16.5, suitable for various sizes and pressure classes:

Diameter of Bolt Circle (P):

Tolerance: ±1.6 mm (±1/16 inch) for flanges through NPS 24, ensuring uniform distribution of bolt loads.

Diameter of Bolt Holes (Q):

Tolerance: Generally oversized relative to the bolt diameter by about +3 mm (1/8 inch), facilitating easier alignment and assembly.

Flange Thickness (T):

Tolerance: Varies but for flanges up to NPS 24, a general guideline is ±3 mm (±1/8 inch). This ensures the flange has adequate strength without unnecessary bulk.

Outside Diameter of Flange (O):

Tolerance: ±1.6 mm (±1/16 inch) for sizes up to NPS 24. This tolerance affects how the flange fits within the system and interfaces with other components.

Thread Dimensions:

The tolerance for the threaded portion of the flange is critical for ensuring a proper fit with the pipe. ASME B1.20.1 provides the standards for pipe threads, and ASME B16.5 references these for threaded flanges to ensure compatibility.

Length Through Hub (Y):

Tolerance: Specific tolerances apply to ensure that the flange aligns correctly with the mating pipe and does not interfere with thread engagement.

Inside Diameter (B):

Tolerance: For threaded flanges, the inside diameter at the base of the thread (or the end of the flange) has a tolerance to ensure that it aligns with the pipe’s outside diameter, facilitating a secure and leak-free connection. The tolerance is typically generous to accommodate the pipe threading.

Facing Finish:

Tolerance: The surface finish of the flange face, which can be critical for seal performance, especially if a gasket is used in conjunction with the threaded connection. Specific Ra values are provided based on the gasket material and type of facing.

Ensuring adherence to these tolerances is crucial for the successful implementation of threaded flanges in a piping system. The precise tolerances enable proper thread engagement, alignment, and sealing capability, which are essential for the operational reliability and safety of the system. For exact tolerance values, especially for specific flange sizes and pressure classes, a direct reference to the ASME B16.5 standard is recommended.

Threaded Flanges Weights

Threaded Flange Weight in Kgs.

The table shows the ASME B16.5 threaded flange (THD) weights in Kgs. by Flange NPS and Class (carbon/alloy steel materials; for higher grades, consider adjusting weight using the delta-specific weight carbon/other grades)

NPS	Class 150	Class 300	Class 400	Class 600	Class 900	Class 1500	Class 2500
1/2	0.5	0.9	0.9	0.9	2.7	2.7	3.2
3/4	0.9	1.4	1.4	1.4	2.7	2.7	4.1
1	0.9	1.4	1.6	1.8	3.4	3.6	5.4
1¼	1.4	2	2	2.3	4.5	4.5	8.1
1½	1.4	2.9	2.9	3.2	6.3	6.3	11.3
2	2.3	3.2	3.6	4.1	9.9	11.3	17.1
2½	3.6	4.5	5.4	5.9	13.9	16.2	24.8
3	4.1	6.3	6.8	7.2	16.2	21.6	37.4
3½	5.4	7.7	9.5	9.5		32.9
4	5.9	10.8	11.7	16.7	23.9		57.2
5	6.8	13.9	13.9	28.4	37.4	59.4	94.5
6	8.6	17.6	19.8	36	49.5	74.3	145.4
8	13.5	26.1	30.2	51.8	77.4	117	218.3
10	19.4	36.5	40	79.7	110.3	196.2	416.3
12	28.8	51.8	58.5	96.8	146.7	300.2	585
14	40.5	74.3	85	116.6	180	423
16	44.1	99	113.9	164.7	206.6	562.5
18	58.5	126	139.5	214.2	291.2	731.3
20	74.3	146.3	170.1	275.4	356.4	922.5
22	83.3	166.5	182.3	265.5
24	99	220.5	242.6	394.2	666	1271

Threaded Flange Weight in Lbs.

The table shows the ASME B16.5 threaded flange (THD) weights in Lbs. by Flange NPS and Class (carbon/alloy steel materials; for higher grades, consider adjusting weight using the delta-specific weight carbon/other grades)

CLASS 150	Nominal Pipe Size	Threaded Weight in Lbs./unit
	½	1
	¾	2
	1	2
	1¼	3
	1½	3
	2	5
	2½	8
	3	9
	3½	12
	4	13
	5	15
	6	19
	8	30
	10	43
	12	64
	14	90
	16	98
	18	130
	20	165
	22	185
	24	220
CLASS 300	Nominal Pipe Size	Threaded Weight in Lbs./unit
	½	2
	¾	3
	1	3
	1¼	4.5
	1½	6.5
	2	7
	2½	10
	3	14
	3½	17
	4	24
	5	31
	6	39
	8	58
	10	81
	12	115
	14	165
	16	220
	18	280
	20	325
	22	370
	24	490
CLASS 400	Nominal Pipe Size	Threaded Weight in Lbs./unit
	½	2
	¾	3
	1	3.5
	1¼	4.5
	1½	6.5
	2	8
	2½	12
	3	15
	3½	21
	4	26
	5	31
	6	44
	8	67
	10	91
	12	130
	14	191
	16	253
	18	310
	20	378
	22	405
	24	539
CLASS 600	Nominal Pipe Size	Threaded Weight in Lbs./unit
	½	2
	¾	3
	1	4
	1¼	5
	1½	7
	2	9
	2½	13
	3	16
	3½	21
	4	37
	5	63
	6	80
	8	115
	10	177
	12	215
	14	259
	16	366
	18	476
	20	612
	22	590
	24	876
CLASS 900	Nominal Pipe Size	Threaded Weight in Lbs./unit
	½	6
	¾	6
	1	7.5
	1¼	10
	1½	14
	2	22
	2½	31
	3	36
	4	53
	5	83
	6	110
	8	172
	10	245
	12	326
	14	400
	16	459
	18	647
	20	792
	24	1480
CLASS 1500	Nominal Pipe Size	Threaded Weight in Lbs./unit
	½	6
	¾	6
	1	8
	1¼	10
	1½	14
	2	25
	2½	36
	3	48
	4	73
	5	132
	6	165
	8	260
	10	436
	12	667
	14	940
	16	1250
	18	1625
	20	2050
	24	2825
CLASS 2500	Nominal Pipe Size	Threaded Weight in Lbs./unit
	½	7
	¾	9
	1	12
	1¼	18
	1½	25
	2	38
	2½	55
	3	83
	4	127
	5	210
	6	323
	8	485
	10	925
	12	1300

Related Articles

• ASME B16.5 Flange Types - Overview of threaded, welding neck, blind, and other flange types
• Flange Pressure Ratings - Pressure-temperature charts for Class 150 to 2500 flanges
• ASTM Materials for Forged Flanges - Carbon steel, stainless steel, and alloy steel flange materials
• ASME B16.11 Forged Fittings - Threaded fittings used with threaded flanges
• Stud Bolts for Flanges - Bolt specifications and torque requirements
• How to Select Flange Gaskets - Gasket selection for threaded flanges
• ASME B16.5 Welding Neck Flange Sizes - Dimensional charts for WN flanges