Reference tables are transcribed from JIS B2220:2012; table numbers, printed page numbers and cell values keep the standard's original wording.
Clause 20 of JIS B2220:2012 defines what a flange must carry: nominal pressure, nominal size and material symbol, a melting or casting number, the manufacturer's name or mark, and any other necessary information. The marking goes on the periphery surface by stamping, die marking, electrolytic etching or spraying, and integral flanges (IT) are exempt.
The marking is shorter than a full product designation. Clause 19 also names the standard, the flange type and the gasket face; the marking itself is the compact string that goes on the metal, with optional letters inserted after the nominal pressure.
StandardJIS B2220:2012
Clause20 (marking), 19 (designation)
Marked onPeriphery surface
MethodsStamping, die marking, etching, spraying
Optional lettersL, H, A, B, C
ExemptIntegral flanges (IT)
What must be marked
Clause 20 lists four items. Items a) to c) are mandatory; item d) allows additional information as long as it cannot be confused with the mandatory marking.
Clause 20 (p. 13) — marking requirements
Clause
What is marked
Detail
a)
Nominal pressure, nominal size and material symbol
The nominal-size letter A is optional.
1)
Letter L after the nominal pressure
Marks a light flange for nominal pressure 10K.
2)
Letter H after the nominal pressure
Marks a welding neck flange (WN) for 5K or 10K made with alternative dimensions.
3)
Letter A, B or C after the nominal pressure
Marks the SOH type at 20K and 30K: Type A, Type B or Type C.
b)
Melting or casting number
Alternatively a quality-control number that can be traced back to the heat or cast number.
c)
Manufacturer's name
Full name, shortened name or trademark.
d)
Other necessary information
Must be distinguishable from the items above.
The marking is applied to the periphery surface by an indelible method: stamping, die marking, electrolytic etching or spraying.
Marking examples
Clause 20 gives nine examples. Read them left to right as pressure, optional letter, size and material symbol.
Clause 20 (p. 13) — marking examples 1 to 9
Example
Marking
What it identifies
1
5K 300 SS 400
5K, nominal size 300 (300A), material SS 400
2
5K 450A SF 390A
5K, 450A, material SF 390A
3
10K 80 SCS 13A
10K, nominal size 80 (80A), material SCS 13A
4
10K H 1000A SFVC 1
10K WN with alternative dimensions, 1000A, material SFVC 1
5
10K L 150 S 20 C
10K light flange, nominal size 150 (150A), material S 20 C
6
16K 200A S 25 C
16K, 200A, material S 25 C
7
20K A 50 SUS F316L
20K SOH Type A, nominal size 50 (50A), material SUS F316L
8
30K C 65A SFVC 2A
30K SOH Type C, 65A, material SFVC 2A
9
40K 100 SFVA F1
40K, nominal size 100 (100A), material SFVA F1
The letter A of the nominal size is left out in examples 1, 3, 5, 7 and 9, which clause 20 a) allows. Examples 4, 5, 7 and 8 also carry the optional letter L, H, A or C after the nominal pressure.
Marking versus product designation
Clause 19 designates a flange by standard number, flange type, gasket face, nominal pressure, nominal size and material symbol, and appends (L), (H) or (A)/(B)/(C) where applicable. The marking on the metal carries the pressure, size and material part of that designation.
Example: the designation JIS B 2220 SOP FF 10K L 150A S 20 C corresponds to the marking 10K L 150 S 20 C.
Zinc-coated white flanges append ZN in the designation; uncoated flanges are black flanges (Table 4).
The marking does not repeat the flange type or the gasket face — those come from the designation and the order.
Integral flanges (IT) are exempt from clause 20 marking.
FAQ
What has to be stamped on a JIS B2220 flange?
Nominal pressure, nominal size and material symbol (the A after the size may be omitted), the melting or casting number or a traceable quality-control number, and the manufacturer's name, abbreviation or trademark. Any extra information must not be confusable with these items, and the marking must be on the periphery by an indelible method.
What do the letters L, H, A, B and C mean in a JIS flange marking?
They are inserted after the nominal pressure: L identifies the light flange for nominal pressure 10K, H identifies welding neck flanges (WN) for 5K and 10K with alternative dimensions, and A/B/C identify the SOH type for 20K and 30K. For example, 10K H 1000A SFVC 1 is a 10K WN flange with alternative dimensions.
Is the flange marking the same as the product designation?
No. The designation also carries the standard number, flange type and gasket face — JIS B 2220 SOP FF 10K L 150A S 20 C — while the marking on the metal is the shorter pressure, size and material string, 10K L 150 S 20 C.
Are integral flanges marked under clause 20?
No. Clause 20 applies to all flanges except integral flanges (IT).
Sources
JIS B2220:2012, clause 20 and marking examples 1 to 9 (PDF p. 18; printed p. 13)
JIS B2220:2012, clause 20 b) to d) (PDF p. 19; printed p. 14)
JIS B2220:2012, clause 19 designation (PDF p. 17; printed p. 12)
JIS B2220:2012, clause 6 and Table 4, black and white flanges (PDF p. 9; printed p. 4)