Buttweld Fittings – Tolerances

Tolerance Chart

All Fittings 90° and 45° Elbows and Tees Reducers and Lap. Joint Stub Ends Caps 180° Returns Lap Joint Stub Ends
NPS Outside(1) Diameter at Bevel Inside(2) Diameter at End Wall(2) Thickness C to E Dimension
A, B, C, M.		 Over all Length
F,H		 Over all Dimension
E		 C to C Dimension
O		 Back to Face Ends
K		 Alignment of Ends
U		 OD of Lap
G		 Thickness of Lap
T		 Fillet Radius of Lap
R		 OD of Barrel
1/2 to 2 1/2 +1 +0.8 Not less than 87.5% of Nominal thickness +2 +2 +4 +7 +7 +1 +0-1 +2-0 +0-1 Refer Below Table
3 to 3 1/2 +1 +1.6 +2 +2 +4 +7 +7 +1 +0-1 +2-0 +0-1
4 +2-1 +1.6 +2 +2 +4 +7 +7 +1 +0-1 +2-0 +0-2
5 to 6 +3-1 +1.6 +2 +2 +7 +7 +7 +1 +0-1 +2-0 +0-2
8 +2 +1.6 +2 +2 +7 +7 +7 +1 +0-1 +2-0 +0-2
10 +4-3 +3.2 +2 +2 +7 +10 +7 +2 +0-2 +2-0 +0-2
                       
12 to 18 +4-3 +3.2 +3 +3 +7 +10 +7 +2 +0-2 +2-0 0-2
                       
20 to 24 +6-5 +4.8 +3 +3 +7 +10 +7 +2 +0-2 +2-0 +0-2
26 to 30 +7-5 +4.8 +3 +3 +10            
32 to 48 +7-5 +4.8 +3 +3 +10            
Outside Diameter of Barrel
Max. Min.
0.896 0.809
1.106 1.019
1.376 1.284
1.716 1.629
1.966 1.869
2.456 2.344
2.966 2.844
3.596 3.469
4.096 3.969
4.593 4.469
5.683 5.532
6.743 6.594
8.743 8.594
10.913 10.719
12.913 12.719
14.170 13.969
16.180 15.969
18.190 17.969
20.240 19.969
22.240 21.969
24.240 23.969
   
Nominal Wall Thickness (f) End Preparation
less than X Cut square ur slightly chamber, at mtr’s option
X’ I0 0.88 incl. [22] Plain bevel as in
Sketch “a" above
more than 0.88 (22) Compound bevel as
in Sketch ”b”aboye
X* = 0.19 (5) Carbon steel cfierritic allay
steal and 0.12(4) foraustenitic alloy steel.		  
Dimensions in parentheses are in millimeters.
Others are in inches.		  
FIGURE 1 WELDING BEVELS AND ROOT FACE  
Nominal Pipe Angularity Tol.
Off Angle Off Plane
Size Q P
1/ 2 to 4 +1 +2
5 to 8 +2 +4
10 to 12 +8 +5
14 to 16 +8 +7
18 to 24 +4 +10
26 to 30 +5 +10
32 to 42 +5 +13
44 to 48 +5 +20