ASME B16.5 Flange Tolerances

- Aug 17, 2017-

Center to contact surface and center to end tolerance

1. Center to contact surface other than ring joint

Size NPS<=10”  Tolerances:+-1.0mm

Size NPS<=12”  Tolerances:+-1.5mm

2. Center to end(Ring joint)

Size NPS<=10”  Tolerances:+-1.0mm

Size NPS<=12”  Tolerances:+-1.5mm

3. Contact surface to contact surface other than ring joint

Size NPS<=10”  Tolerances:+-2.0mm

Size NPS<=12”  Tolerances:+-3.0mm

4. End to end(Ring joint)

Size NPS<=10”  Tolerances:+-2.0mm

Size NPS<=12”  Tolerances:+-3.0mm

Facing

1. Inside and outside diameter of large and small tongue and groove and female,+-0.5mm

2. outside diameter, 2.0mm raised face, +-1.0mm

3. outside diameter, 7.0mm raised face, +-0.5mm

Flange thickness

Size NPS<=18”  Tolerances: +3.0mm, -0.0mm

Size NPS<=12”  Tolerances: +5.0mm, -0.0mm

Welding end flange ends and hubs

Outside:

Size NPS<=5”  Tolerances: +2.0mm, -1.0mm

Size NPS<=6”  Tolerances: +4.0mm, -1.0mm

Inside Diameter

1. For figs. 8 and 9

Size NPS<=10”  Tolerances: +-1.0mm,

Size 12<=NPS<=18”  Tolerances: +-1.5mm

Size NPS>=20”  Tolerances:+3.0,-1.5mm

2. For Fig. 10

Size NPS<=10”  Tolerances: +-0.0mm, -1.0mm

Size NPS<=12”  Tolerances: +-0.0mm, -1.5mm

 

Backing ring contact surface

2<=NPS<=24”  Tolerances: +0.25,-0.0mm

 

Length through hub on welding neck flanges

Size NPS<=4”  Tolerances: +-1.5mm

Size 5<=NPS<=10  Tolerances: +1.5, -3.0mm

Size NPS>=12  Tolerances: +3.0,-5.0mm

 

Flange bore diameter

Lapped and slip on flange bores

Size NPS<=10”  Tolerances: +1.0,-0.0mm

Size NPS>=12”  Tolerances: +1.5,-0.0mm

Counter bores, threaded flange

Size: NPS<=10”  Tolerances: +1.0,-0.0mm

Size: NPS>=12”  Tolerances: +1.5,-0.0mm

Counter bores, Socket welding flanges

1/2”<=NPS<=3”  Tolerances:+-0.25mm

Drilling and facing

Bolt circle diameter:  +-1.5mm

Bolt Hole to bolt hole: +-0.8mm

Bolt Circle concentricity

Size: NPS<=2 1/2”  Tolerances: 0.8mm

Size: NPS>=3”      Tolerances:1.5mm