ASME/ANSI B16.5-1996 and B16.47-1996

Tolerances on flange dimensions (ASME/ANSI B16.5 and B16.7, and MSS SP-44)

Dimension

Range

Tolerance

in

mm

General and Blind Flanges(For blind flange dimendions see page 8-23 for
B16.5, page8-46 for B16.47 Series A/ MSS SP-44 and page 8-51 for B16.47 
Series B/ API 605):

G(raised face
 diameter)

≤NPS 24

±0.03

±0.76

≥NPS 26,with
0.06 inraised face

±0.08

±2.03

≥NPS 26,with
0.25 inraised face

±0.04

±1.02

I(bolt hole diameter)

All

No tolerance in B16.5 or B 16.47

J(bolt circle diameter)

All

±0.06

±1.52

Center to center of 
adjacent bolt holes

All

±0.03

±0.76

Eccenticity of bolt 
circle and machined facing diameters

≤NPS 2½

±0.03

±0.76

≥NPS 3

±0.06

±1.52

Weld Neck Flanges1 (For dimensions see page 8-10 for B 16.5, page 8-46 for 
B16.47 Series A/ MSS SP-44 and page 8-51 for B16.47 Series B/ API 605):

D(overall length)

≤NPS 4

﹢0.06

﹢1.52

NPS 5 to 10

﹢0.06,﹣0.12

﹢1.52,﹣3.05

NPS 12 to 24

﹢0.12,﹣0.18

﹢3.05,﹣4.57

≥NPS 26

±0.19

±4.83

Thickness of hub

All

>87.5% of pipe nominal wall thickness

Slip on(see page 8-17),Lap Joint(see page8-32) and Socket Welding(see page
8-30 for dimensions) Flanges:

B(inside diameter,or
bore)

≤NPS10

﹢0.03,﹣0.0

﹢0.76,﹣0.0

≥NPS12

﹢0.06,﹣0.0

﹢1.52,﹣0.0

Threaded Flanges (see page 8-40 for dimensions):

B(counterbore)
(Not applicable for
Class150 lb

≤NPS10

﹢0.03,﹣0.0

﹢0.76,﹣0.0

≥NPS12

﹢0.06,﹣0.0

﹢1.52,﹣0.0