Nominal Pipe Size (NPS)	Outside diameter at Bevel D		Length(2) E	Limiting wall Thickness for Length E	Length(3) E1
1/2	21.3		25.4	4.6	25.4
3/4	26.7		25.4	3.8	25.4
1	33.4		38.1	4.6	38.1
1­1/4	42.2		38.1	4.8	38.1
1­1/2	48.3		38.1	5.1	38.1
2	60.3		38.1	5.6	44.4
2­1/2	73.0		38.1	7.1	50.8
3	88.9		50.8	7.6	63.5
3­1/2	101.6		63.5	8.1	76.2
4	114.3		63.5	8.6	76.2
5	141.3		76.2	9.7	88.9
6	168.3		88.9	10.9	101.6
8	219.1		101.6	12.7	127.0
10	273.1		127.0	12.7	152.4
12	323.9		152.4	12.7	177.8
14	355.6		165.1	12.7	190.5
16	406.4		177.8	12.7	203.2
18	457.2		203.2	12.7	228.6
20	508.0		228.6	12.7	254.0
22	558.8		254.0	12.7	254.0
24	609.6		266.7	12.7	304.8
26	660.4		266.7
28	711.2		266.7
30	762.0		266.7
32	812.8		266.7
34	863.4		266.7
36	914.4		266.7
38	965.2		304.8
40	1016.0		304.8
42	1066.8		304.8
44	1117.6		342.9
46	1168.4		342.9
48	1219.2		342.9

Wall thickness for caps up to and including 36" conform to ANSI B36.10 specifications. Caps 38" and larger conform to XS specifications for wall thickness of 36". These are Wellgrow's standards as no intemationally recognized standards have been set for such large size wall thickness.
(1) The shape of these caps shall be ellipsoidal and shall conform to the shape requirements as given in the ASME boiler and pressure vessel code.
(2) Length E applies for thickness not exceeding that given in column“limiting wall thickness for length E”.
(3) Length E1 applies for thickness greater than given in column “limiting wall thickness” for NPS 24 and smaller.For NPS 26 and larger,length E1 shall be by agreement between manufacturer and purchaser.