Dimensions of ASME B16.9 Lap Joint Stub Ends

Nominal Size	Outside Diameter of Barrel		Long Pattern Length, F	Short Pattern Length, F	Radius of Fillet, R	Diameter of Lap, G
NPS	Max. mm. in.	Min. mm. in.	mm. in.	mm. in.	mm. in.	mm. in.
1/2	22.8 0.896	20.5 0.809	76 3.00	51 2.00	3 0.12	35 1.38
3/4	28.1 1.106	25.9 1.019	76 3.00	51 2.00	3 0.12	43 1.69
1	35.0 1.376	32.6 1.284	102 4.00	51 2.00	3 0.12	51 2.00
1 1/4	43.6 1.716	41.4 1.629	102 4.00	51 2.00	5 0.19	64 2.50
1 1/2	49.9 1.965	47.5 1.869	102 4.00	51 2.00	6 0.25	73 2.88
2	62.4 2.456	59.5 2.344	152 6.00	64 2.50	8 0.31	92 3.62
2 1/2	75.3 2.966	72.2 2.844	152 6.00	64 2.50	8 0.31	105 4.12
3	91.3 3.596	88.1 3.469	152 6.00	64 2.50	10 0.38	127 5.00
3 1/2	104.0 4.096	100.8 3.969	152 6.00	76 3.00	10 0.38	140 5.50
4	116.7 4.593	113.5 4.469	152 6.00	76 3.00	11 0.44	157 6.19
5	144.3 5.683	140.5 5.532	203 8.00	76 3.00	11 0.44	186 7.31
6	171.3 6.743	167.5 6.594	203 8.00	89 3.50	13 0.50	216 8.50
8	222.1 8.743	218.3 8.594	203 8.00	102 4.00	13 0.50	270 10.62
10	277.2 10.913	272.3 10.719	254 10.00	127 5.00	13 0.50	324 12.75
12	328.0 12.913	323.1 12.719	254 10.00	152 6.00	13 0.50	381 15.00
14	359.9 14.170	354.8 13.969	305 12.00	152 6.00	13 0.50	413 16.25
16	411.0 16.180	405.6 15.969	305 12.00	152 6.00	13 0.50	470 18.50
18	462.0 18.190	456.0 17.969	305 12.00	152 6.00	13 0.50	533 21.00
20	514.0 20.240	507.0 19.969	305 12.00	152 6.00	13 0.50	584 23.00
22	565.0 22.240	558.0 21.969	305 12.00	152 6.00	13 0.50	641 25.25
24	616.0 24.240	609.0 23.969	305 12.00	152 6.00	13 0.50	692 27.25

*All dimensions are furnished in both SI(metric) units and US Customary units.
*Gasket face finish shall be in accordance with ASME B16.5 for raised face flanges.
*The lap thickness, T, shall not be less than nominal pipe wall thickness.
*When short pattern stub ends are used with larger flanges in Classes 300 and 600, with most sizes in Classes 900 and higher, and when long pattern stub ends are used with larger flanges in Classes 1500 and 2500, it may be necessary to increase the length of the stub ends in order to avoid covering the weld with the flange.
*When special facings such as tongue and groove, male and female, etc., are employed, additional lap thickness must be provided and such additional thickness shall be in addition to (not included in) the basic length, F.
*Dimensions of “Radius of Fillet, R” conform to the radius established for lap joint flanges in ASME B16.5.
*Dimensions of “Diameter of Lap, G” conform to standard machined facings shown in ASME B16.5.

View more specification of ASME B16.9.