JIS B2220 · Standard reference
JIS B2220 dimensional tolerances (Table 22)
Table 22 of JIS B2220:2012 sets the dimensional tolerances for steel pipe flanges, in millimetres. Clause 12.5 makes the table the reference for flange tolerances and adds a separate perpendicularity limit for threaded flanges.
The table is organised by dimension, flange classification, gasket face and dimensional division (a size band). Most tolerances are symmetric (±). Thickness, hub, bore and chamfer tolerances are given as plus/zero or zero/minus values, and the outside diameter of an integral flange has no specified plus deviation at all. The figures at the head of the table show where each symbol is measured.
- Standard
- JIS B2220:2012
- Table
- Table 22, clause 12.5
- Unit
- mm
- Dimensions covered
- 16
- Size bands
- 6 mm to over 1 500 mm
- Thread limit
- 0.9 mm per 100 mm
Part 1 — outside diameter, bolt holes, bore and gasket face
Each row is read as dimension, flange classification, gasket face and size band. Where a dimension applies to all flange types, the classification and gasket-face columns are dash. The C₁ to C₄ diameters and the f₃/f₄ heights apply only to the male-female and tongue-and-groove faces.
JIS B2220 · JIS B2220:2012
| Name of dimension | Classification of flange | Gasket face | Dimensional division mm | Dimensional tolerance mm |
|---|---|---|---|---|
| Outside diameter of flange D | Except IT | — | 600 or under | ±1.5 |
| Outside diameter of flange D | Except IT | — | Over 600 | ±3 |
| Outside diameter of flange D | IT | — | 1 000 or under | + not specified / −2 |
| Outside diameter of flange D | IT | — | Over 1 000 | + not specified / −3 |
| Diameter of bolt hole centre circle C | All | — | 950 or under | ±0.8 |
| Diameter of bolt hole centre circle C | All | — | Over 950 | ±1.5 |
| Eccentricity of bolt hole centre circle with respect to the inside diameter | All | — | — | Within 0.8 |
| Pitch of bolt hole | All | — | — | ±0.8 |
| Diameter of bolt hole h | All | — | — | ±0.5 |
| Inside diameter d₀ | SOP, SOH, SW, LJ | — | 400 or under | +1 / 0 |
| Inside diameter d₀ | SOP, SOH, SW, LJ | — | Over 400 up to and incl. 600 | +1.5 / 0 |
| Inside diameter d₀ | SOP, SOH, SW, LJ | — | Over 600 up to and incl. 800 | +2 / 0 |
| Inside diameter d₀ | SOP, SOH, SW, LJ | — | Over 800 up to and incl. 1 000 | +2.5 / 0 |
| Inside diameter d₀ | SOP, SOH, SW, LJ | — | Over 1 000 | +3 / 0 |
| Inside diameter d | SW, WN | — | 100 or under | 0 / −0.5 |
| Inside diameter d | SW, WN | — | Over 100 up to and incl. 400 | 0 / −1 |
| Inside diameter d | SW, WN | — | Over 400 up to and incl. 600 | 0 / −1.5 |
| Inside diameter d | SW, WN | — | Over 600 up to and incl. 800 | 0 / −2 |
| Inside diameter d | SW, WN | — | Over 800 up to and incl. 1 000 | 0 / −2.5 |
| Inside diameter d | SW, WN | — | Over 1 000 | 0 / −3 |
| Diameter of gasket face g | SOH, SW, TR, WN, IT, BL | RF, MF, TG | 700 or under | ±0.8 |
| Diameter of gasket face g | SOH, SW, TR, WN, IT, BL | RF, MF, TG | Over 700 | ±1.5 |
| Diameter of gasket face C₁, C₂, C₃, C₄ | Except LJ | MF, TG | 500 or under | ±0.3 |
| Diameter of gasket face C₁, C₂, C₃, C₄ | Except LJ | MF, TG | Over 500 up to and incl. 1 000 | ±0.35 |
| Diameter of gasket face C₁, C₂, C₃, C₄ | Except LJ | MF, TG | Over 1 000 up to and incl. 1 500 | ±0.4 |
| Diameter of gasket face C₁, C₂, C₃, C₄ | Except LJ | MF, TG | Over 1 500 | ±0.5 |
| Height of gasket face f₃, f₄ | Except LJ | MF, TG | — | ±0.2 |
Dimensional divisions and tolerances are in mm. '+ not specified / −2' means that the standard sets only the minus deviation (2 mm) and leaves the plus deviation unspecified. The symbols are shown in the figures above Table 22; d₀ is the inside diameter of SOP, SOH, SW and LJ flanges, while d is the bore of SW and WN flanges.
Part 2 — thickness, hub, length and chamfer
The thickness tolerances are one-sided (+/0), while total length T is ±2 mm for SOH, SW, LJ and TR flanges and +/0 for WN. The last row controls the squareness of the bolt and nut contact face to the gasket face.
JIS B2220 · JIS B2220:2012
| Name of dimension | Classification of flange | Gasket face | Dimensional division mm | Dimensional tolerance mm |
|---|---|---|---|---|
| Thickness of flange t a) b) | Except LJ | FF, MF, TG | 20 or under | +1.5 / 0 |
| Thickness of flange t a) b) | Except LJ | FF, MF, TG | Over 20 up to and incl. 50 | +2 / 0 |
| Thickness of flange t a) b) | Except LJ | FF, MF, TG | Over 50 | +3 / 0 |
| Thickness of flange t a) b) | LJ | — | 20 or under | +1.5 / 0 |
| Thickness of flange t a) b) | LJ | — | Over 20 up to and incl. 50 | +2 / 0 |
| Thickness of flange t a) b) | LJ | — | Over 50 | +3 / 0 |
| Thickness of flange t − f a) b) | SOH, SW, TR, WN, IT, BL | RF | 20 or under | +1.5 / 0 |
| Thickness of flange t − f a) b) | SOH, SW, TR, WN, IT, BL | RF | Over 20 up to and incl. 50 | +2 / 0 |
| Thickness of flange t − f a) b) | SOH, SW, TR, WN, IT, BL | RF | Over 50 | +3 / 0 |
| Diameter of hub, small diameter side a | SOH, SW, LJ, TR, WN | — | 220 or under | +2 / 0 |
| Diameter of hub, small diameter side a | SOH, SW, LJ, TR, WN | — | Over 220 up to and incl. 650 | +4 / 0 |
| Diameter of hub, small diameter side a | SOH, SW, LJ, TR, WN | — | Over 650 | +8 / 0 |
| Total length of flange T | SOH, SW, LJ, TR | — | — | ±2 |
| Total length of flange T | WN | — | 200 or under | +2 / 0 |
| Total length of flange T | WN | — | Over 200 | +3 / 0 |
| Chamfering c | LJ | — | 6 or under | +0.8 / 0 |
| Chamfering c | LJ | — | Over 6 | +1.6 / 0 |
| Inclination of bolt · nut face with respect to gasket face | Except LJ | All | — | Within 1 degree |
- a) For integral flanges (IT) of piping parts where the dimension between flange facings is limited to a specific value, the thickness tolerance may be twice the value shown.
- b) For flanges to be given spot facing, the spot-facing thickness may have a minus-side tolerance of up to 70 % of the tabulated thickness tolerance.
Dimensional divisions and tolerances are in mm. t is the flange thickness and t − f is the thickness under the raised face. The a) and b) markers on the thickness rows are explained in the footnotes.
Thread perpendicularity (clause 12.5)
Table 22 does not cover the thread. Clause 12.5 adds a separate requirement for threaded flanges (TR):
- The axis of the thread must be perpendicular to the gasket face within 0.9 mm per 100 mm of the thread axis.
- Perpendicularity is defined in 5.8 of JIS B 0621.
- The thread itself is made to JIS B 0203 (clause 12.4).
JIS B2220 tolerances — questions
What is the tolerance on a JIS flange outside diameter?
For every flange type except integral flanges (IT): ±1.5 mm up to and including 600 mm outside diameter, and ±3 mm above 600 mm. Integral flanges have no designated plus deviation: −2 mm up to 1 000 mm and −3 mm above 1 000 mm.
How much can a JIS B2220 flange thickness vary?
Thickness t is +1.5/0 mm at 20 mm or less, +2/0 mm above 20 up to and including 50 mm, and +3/0 mm above 50 mm; the t − f thickness under a raised face uses the same bands. Integral flanges in fixed face-to-face piping may use twice the tolerance, and spot-faced flanges may use up to 70 % of the tolerance on the minus side (footnotes a and b).
What tolerance applies to the bolt circle and bolt holes?
Bolt circle diameter C is ±0.8 mm up to and including 950 mm and ±1.5 mm above 950 mm. Bolt hole pitch is ±0.8 mm and bolt hole diameter h is ±0.5 mm. Eccentricity of the bolt circle with respect to the inside diameter must be within 0.8 mm.
Do the same tolerances apply to every flange type?
No. Table 22 gives different rules for outside diameter (IT vs all other types), inside diameter (d₀ for SOP, SOH, SW and LJ; d for SW and WN) and gasket-face dimensions. Read the classification and gasket-face columns together with the dimension.