Slip-on flanges are similar to Socket Weld Flanges, but without an internal shoulder. Because of this design, welding is typically performed on both the internal and external sides of the flange connection to improve structural integrity.

Slip-on flanges are commonly used for larger pipe sizes and are generally more popular than Welding Neck Flanges due to their lower cost and shorter hub length, which requires less installation space.

Available Pressure Classes

American Standard: CLASS 150, CLASS 300, CLASS 400, CLASS 600, CLASS 900 and CLASS 1500
European Standard: PN 6, PN 10, PN 16, PN 25, PN 40, PN 63 and PN 100

Slip-On Flange Dimensions — Class 150 (ASME B16.5)

Slip-On Flange (SO) · Scroll the table to the right to see more columns

Cross-section of a Class 150 slip-on flange showing dimensions X, B, Y, C and R, and the 0.06 in (1.6 mm) raised face — Dimension callouts for a slip-on flange — X hub diameter · B bore · Y hub length · C thickness · R raised-face diameter

Slip-On Flange (SO) — ASME B16.5 Class 150 · NPS 1/2 – 24 (DN 15 – 600)
Size		Dimension (mm)					Bolting (in)
NPS	DN	O	C	X	Y	B	No.	Hole ø	Bolt ø
1/2	15	89	9.7	30	14	22.4	4	5/8	1/2
3/4	20	99	11.2	38	14	27.7	4	5/8	1/2
1	25	108	12.7	49	16	34.5	4	5/8	1/2
1 1/4	32	117	14.2	59	19	43.2	4	5/8	1/2
1 1/2	40	127	15.9	65	21	49.5	4	5/8	1/2
2	50	152	17.5	78	24	61.9	4	3/4	5/8
3	80	190	22.4	108	28	90.7	4	3/4	5/8
4	100	229	22.4	135	32	116.1	8	3/4	5/8
5	125	254	22.4	164	35	143.8	8	7/8	3/4
6	150	279	23.9	192	38	170.7	8	7/8	3/4
8	200	343	26.9	246	43	221.5	8	7/8	3/4
10	250	406	28.4	305	48	276.4	12	1	7/8
12	300	483	30.2	365	54	327.2	12	1	7/8
14	350	533	33.3	400	56	359.2	12	1 1/8	1
16	400	597	35.1	457	62	410.5	16	1 1/8	1
18	450	635	38.1	505	67	461.8	16	1 1/4	1 1/8
20	500	698	41.1	559	71	513.1	20	1 1/4	1 1/8
24	600	813	46.0	663	81	616.0	20	1 3/8	1 1/4

NOTES: (1) Dimensions O, C, X, Y, B are in millimeters per ASME B16.5-2020 Table 7 and Table 8.
(2) Diameters of bolt holes and bolts are in inches per Table 7.
This information is for preliminary reference only. Please confirm specifications with our sales team before ordering — call 02-896-7744 or LINE @skfitting

Slip-On Flange Dimensions — Class 300 (ASME B16.5)

Slip-On Flange (SO) · Scroll the table to the right to see more columns

Cross-section of a Class 300 slip-on flange showing dimensions X, B, Y, C and R, and the 0.06 in (1.6 mm) raised face — Dimension callouts for a slip-on flange — X hub diameter · B bore · Y hub length · C thickness · R raised-face diameter

Slip-On Flange (SO) — ASME B16.5 Class 300 · NPS 1/2 – 24 (DN 15 – 600)
Size		Dimension (mm)					Bolting (in)
NPS	DN	O	C	X	Y	B	No.	Hole ø	Bolt ø
1/2	15	95	12.7	38	21	22.4	4	5/8	1/2
3/4	20	117	14.2	48	24	27.7	4	3/4	5/8
1	25	124	15.7	54	25	34.5	4	3/4	5/8
1 1/4	32	133	17.5	64	25	43.2	4	3/4	5/8
1 1/2	40	155	19.0	70	29	49.5	4	7/8	3/4
2	50	165	20.6	84	32	62.0	8	3/4	5/8
2 1/2	65	190	23.9	100	37	74.7	8	7/8	3/4
3	80	210	26.9	117	41	90.7	8	7/8	3/4
3 1/2	90	229	28.4	133	43	103.4	8	7/8	3/4
4	100	254	30.2	146	46	116.1	8	7/8	3/4
5	125	279	33.3	178	49	143.8	8	7/8	3/4
6	150	318	35.1	206	51	170.7	12	7/8	3/4
8	200	381	39.6	260	60	221.5	12	1	7/8
10	250	444	46.0	321	65	276.4	16	1 1/8	1
12	300	521	49.3	375	72	327.2	16	1 1/4	1 1/8
14	350	584	52.3	425	75	359.2	20	1 1/4	1 1/8
16	400	648	55.6	483	81	410.5	20	1 3/8	1 1/4
18	450	711	58.7	533	87	461.8	24	1 3/8	1 1/4
20	500	775	62.0	587	94	513.1	24	1 3/8	1 1/4
24	600	914	68.3	702	105	616.0	24	1 5/8	1 1/2

NOTES: (1) Dimensions O, C, X, Y, B are in millimeters per ASME B16.5-2020 Table 10 and Table 11.
(2) Diameters of bolt holes and bolts are in inches per Table 10.
This information is for preliminary reference only. Please confirm specifications with our sales team before ordering — call 02-896-7744 or LINE @skfitting

Slip-On Flange Dimensions — Class 1500 (ASME B16.5)

Slip-On Flange (SO) · Scroll the table to the right to see more columns

Cross-section of a Class 1500 slip-on flange showing dimensions X, B, Y, C and R, and the 0.25 in (6.4 mm) raised face — Dimension callouts for a slip-on flange — X hub diameter · B bore · Y hub length · C thickness · R raised-face diameter

Slip-On Flange (SO) — ASME B16.5 Class 1500 · NPS 1/2 – 24 (DN 15 – 600)
Size		Dimension (mm)					Bolting (in)
NPS	DN	O	C	X	Y	B	No.	Hole ø	Bolt ø
1/2	15	121	22.4	38	32	22.4	4	7/8	3/4
3/4	20	130	25.4	44	35	27.7	4	7/8	3/4
1	25	149	28.4	52	41	34.5	4	1	7/8
1 1/4	32	159	28.4	64	41	43.2	4	1	7/8
1 1/2	40	178	31.8	70	44	49.5	4	1 1/8	1
2	50	216	38.1	105	57	62.0	8	1	7/8
2 1/2	65	244	41.1	124	64	74.7	8	1 1/8	1
3	80	267	47.8	133	…	…	8	1 1/4	1 1/8
4	100	311	53.8	162	…	…	8	1 3/8	1 1/4
5	125	375	73.2	197	…	…	8	1 5/8	1 1/2
6	150	394	82.6	229	…	…	12	1 1/2	1 3/8
8	200	483	91.9	292	…	…	12	1 3/4	1 5/8
10	250	584	108.0	368	…	…	12	2	1 7/8
12	300	673	124.0	451	…	…	16	2 1/8	2
14	350	749	133.4	495	…	…	16	2 3/8	2 1/4
16	400	826	146.0	552	…	…	16	2 5/8	2 1/2
18	450	914	162.1	597	…	…	16	2 7/8	2 3/4
20	500	984	177.8	641	…	…	16	3 1/8	3
24	600	1168	203.2	762	…	…	16	3 5/8	3 1/2

NOTES: (1) Dimensions O, C, X, Y, B are in millimeters per ASME B16.5-2020 Table 20.
(2) Diameters of bolt holes and bolts are in inches per Table 19.
… means the standard does not define this dimension for that size
This information is for preliminary reference only. Please confirm specifications with our sales team before ordering — call 02-896-7744 or LINE @skfitting

Slip-On Flange Dimensions — Class 400 (ASME B16.5)

Slip-On Flange (SO) · Scroll the table to the right to see more columns

Cross-section of a Class 400 slip-on flange showing dimensions X, B, Y, C and R, and the 0.25 in (6.4 mm) raised face — Dimension callouts for a slip-on flange — X hub diameter · B bore · Y hub length · C thickness · R raised-face diameter

Slip-On Flange (SO) — ASME B16.5 Class 400 · NPS 1/2 – 24 (DN 15 – 600)
Size		Dimension (mm)					Bolting (in)
NPS	DN	O	C	X	Y	B	No.	Hole ø	Bolt ø
1/2	15	95	14.2	38	22	22.4	4	5/8	1/2
3/4	20	117	15.7	48	25	27.7	4	3/4	5/8
1	25	124	17.5	54	27	34.5	4	3/4	5/8
1 1/4	32	133	20.6	64	28	43.2	4	3/4	5/8
1 1/2	40	155	22.4	70	32	49.5	4	7/8	3/4
2	50	165	25.4	84	37	62.0	8	3/4	5/8
2 1/2	65	190	28.4	100	41	74.7	8	7/8	3/4
3	80	210	31.8	117	46	90.7	8	7/8	3/4
3 1/2	90	229	35.1	133	49	103.4	8	1	7/8
4	100	254	35.1	146	51	116.1	8	1	7/8
5	125	279	38.1	178	54	143.8	8	1	7/8
6	150	318	41.1	206	57	170.7	12	1	7/8
8	200	381	47.8	260	68	221.5	12	1 1/8	1
10	250	444	53.8	321	73	276.4	16	1 1/4	1 1/8
12	300	521	57.2	375	79	327.2	16	1 3/8	1 1/4
14	350	584	60.5	425	84	359.2	20	1 3/8	1 1/4
16	400	648	63.5	483	94	410.5	20	1 1/2	1 3/8
18	450	711	66.5	533	99	461.8	24	1 1/2	1 3/8
20	500	775	69.8	587	102	513.1	24	1 5/8	1 1/2
24	600	914	76.2	702	114	616.0	24	1 7/8	1 3/4

NOTES: (1) Dimensions O, C, X, Y, B are in millimeters per ASME B16.5-2020 Table 14.
(2) Diameters of bolt holes and bolts are in inches per Table 13.
Note: NPS 1/2 through 3 1/2 use Class 600 dimensions and drilling, as directed by ASME B16.5.
This information is for preliminary reference only. Please confirm specifications with our sales team before ordering — call 02-896-7744 or LINE @skfitting

Slip-On Flange Dimensions — Class 600 (ASME B16.5)

Slip-On Flange (SO) · Scroll the table to the right to see more columns

Cross-section of a Class 600 slip-on flange showing dimensions X, B, Y, C and R, and the 0.25 in (6.4 mm) raised face — Dimension callouts for a slip-on flange — X hub diameter · B bore · Y hub length · C thickness · R raised-face diameter

Slip-On Flange (SO) — ASME B16.5 Class 600 · NPS 1/2 – 24 (DN 15 – 600)
Size		Dimension (mm)					Bolting (in)
NPS	DN	O	C	X	Y	B	No.	Hole ø	Bolt ø
1/2	15	95	14.2	38	22	22.4	4	5/8	1/2
3/4	20	117	15.7	48	25	27.7	4	3/4	5/8
1	25	124	17.5	54	27	34.5	4	3/4	5/8
1 1/4	32	133	20.6	64	28	43.2	4	3/4	5/8
1 1/2	40	155	22.4	70	32	49.5	4	7/8	3/4
2	50	165	25.4	84	37	62.0	8	3/4	5/8
2 1/2	65	190	28.4	100	41	74.7	8	7/8	3/4
3	80	210	31.8	117	46	90.7	8	7/8	3/4
3 1/2	90	229	35.1	133	49	103.4	8	1	7/8
4	100	273	38.1	152	54	116.1	8	1	7/8
5	125	330	44.4	189	60	143.8	8	1 1/8	1
6	150	356	47.8	222	67	170.7	12	1 1/8	1
8	200	419	55.6	273	76	221.5	12	1 1/4	1 1/8
10	250	508	63.5	343	86	276.2	16	1 3/8	1 1/4
12	300	559	66.5	400	92	327.0	20	1 3/8	1 1/4
14	350	603	69.8	432	94	359.2	20	1 1/2	1 3/8
16	400	686	76.2	495	106	410.5	20	1 5/8	1 1/2
18	450	743	82.6	546	117	461.8	20	1 3/4	1 5/8
20	500	813	88.9	610	127	513.1	24	1 3/4	1 5/8
24	600	940	101.6	718	140	616.0	24	2	1 7/8

NOTES: (1) Dimensions O, C, X, Y, B are in millimeters per ASME B16.5-2020 Table 16.
(2) Diameters of bolt holes and bolts are in inches per Table 15.
This information is for preliminary reference only. Please confirm specifications with our sales team before ordering — call 02-896-7744 or LINE @skfitting

Slip-On Flange Dimensions — Class 900 (ASME B16.5)

Slip-On Flange (SO) · Scroll the table to the right to see more columns

Cross-section of a Class 900 slip-on flange showing dimensions X, B, Y, C and R, and the 0.25 in (6.4 mm) raised face — Dimension callouts for a slip-on flange — X hub diameter · B bore · Y hub length · C thickness · R raised-face diameter

Slip-On Flange (SO) — ASME B16.5 Class 900 · NPS 1/2 – 24 (DN 15 – 600)
Size		Dimension (mm)					Bolting (in)
NPS	DN	O	C	X	Y	B	No.	Hole ø	Bolt ø
1/2	15	121	22.4	38	32	22.4	4	7/8	3/4
3/4	20	130	25.4	44	35	27.7	4	7/8	3/4
1	25	149	28.4	52	41	34.5	4	1	7/8
1 1/4	32	159	28.4	64	41	43.2	4	1	7/8
1 1/2	40	178	31.8	70	44	49.5	4	1 1/8	1
2	50	216	38.1	105	57	62.0	8	1	7/8
2 1/2	65	244	41.1	124	64	74.7	8	1 1/8	1
3	80	241	38.1	127	54	90.7	8	1	7/8
4	100	292	44.5	159	70	116.1	8	1 1/4	1 1/8
5	125	349	50.8	190	79	143.8	8	1 3/8	1 1/4
6	150	381	55.6	235	86	170.7	12	1 1/4	1 1/8
8	200	470	63.5	298	102	221.5	12	1 1/2	1 3/8
10	250	546	69.8	368	108	276.4	16	1 1/2	1 3/8
12	300	610	79.2	419	117	327.2	20	1 1/2	1 3/8
14	350	641	85.9	451	130	359.2	20	1 5/8	1 1/2
16	400	705	88.9	508	133	410.5	20	1 3/4	1 5/8
18	450	787	101.6	565	152	461.8	20	2	1 7/8
20	500	857	108.0	622	159	513.1	20	2 1/8	2
24	600	1041	139.7	749	203	616.0	20	2 5/8	2 1/2

NOTES: (1) Dimensions O, C, X, Y, B are in millimeters per ASME B16.5-2020 Table 18.
(2) Diameters of bolt holes and bolts are in inches per Table 17.
Note: NPS 1/2 through 2 1/2 use Class 1500 dimensions and drilling, as directed by ASME B16.5. The standard does not define NPS 3 1/2 in this class.
This information is for preliminary reference only. Please confirm specifications with our sales team before ordering — call 02-896-7744 or LINE @skfitting

Standard	JIS, ANSI, DIN/EN
Pressure rating	5K, 10K, 16K, 20K, 30K, 40K, 63K, 150P, 300P, 600P, 900P, 1500P, 2500P, PN6, PN10, PN16, PN25, PN40, PN63, PN64, PN100
Material	Carbon Steel (SS400/A105), Carbon Steel Hot-Dip Galvanized (HDG), Stainless Steel 304, Stainless Steel 316, Stainless Steel 316L
Size	3/8", 1/2", 3/4", 1", 1-1/4", 1-1/2", 2", 2-1/2", 3", 4", 5", 6", 8", 10", 12", 14", 16", 18", 20", 22", 24", 26", 28", 30", 32", 36", 40", 42", 48"