Overview of the JIS Piping System
JIS piping standards are organized by material and service. The G-series covers pipe and tube products, while the B-series covers flanges, fittings and joining components. Grades are named with letters that indicate the product type followed by numbers that indicate the minimum tensile strength in megapascals, so the designation itself carries engineering information.
Carbon Steel Pipe Standards
The table lists the carbon steel pipe standards most often encountered in industrial projects.
| Standard | Grade Examples | Scope |
|---|---|---|
| JIS G3452 | SGP | Carbon steel pipe for ordinary piping, water, gas, steam and air at low pressure |
| JIS G3454 | STPG370, STPG410 | Carbon steel pipe for pressure service |
| JIS G3455 | STS370, STS410, STS480 | Carbon steel pipe for high-pressure service |
| JIS G3456 | STPT370, STPT410, STPT480 | Carbon steel pipe for high-temperature service |
| JIS G3457 | STPY400, STPY410 | Arc-welded carbon steel pipe for general service |
G3452 SGP is the everyday white pipe for buildings and plants. G3454 STPG is the pressure pipe equivalent used in boilers and chemical plants. G3455 STS adds higher strength for high-pressure service, G3456 STPT is optimized for high-temperature duty, and G3457 STPY is the welded alternative for large diameters.
Alloy and Stainless Steel Pipe Standards
JIS G3458 covers chromium-molybdenum alloy steel pipes, and JIS G3459 covers stainless steel pipes for corrosion-resistant service.
| Standard | Grade Examples | Scope |
|---|---|---|
| JIS G3458 | STPA22, STPA23, STPA24, STPA25, STPA26 | Alloy steel pipes for high-temperature service, chromium-molybdenum grades |
| JIS G3459 | SUS304TP, SUS316TP, SUS304LTP | Stainless steel pipes for piping service |
| JIS G3468 | SUS304, SUS316 | Arc-welded large-diameter stainless steel pipes |
In the G3458 designations, STPA22 is 1% chromium-0.5% molybdenum, STPA23 is 1.25% chromium-0.5% molybdenum, STPA24 is 2.25% chromium-1% molybdenum, STPA25 is 5% chromium and STPA26 is 9% chromium, matching the familiar chromium-molybdenum boiler pipe grades of other standards.
Flange and Fitting Standards
The B-series standards define the joining hardware used with these pipes.
| Standard | Scope |
|---|---|
| JIS B2220 | Steel pipe flanges, the primary flange standard for piping systems |
| JIS B2201 | Pressure ratings for ferritic pipe flanges |
| JIS B2210 | Basic dimensions of ferritic pipe flanges |
| JIS B2302 | Steel threaded fittings |
| JIS B2311 | General-purpose steel butt-welding fittings |
| JIS B2312 | Steel butt-welding fittings |
| JIS B2313 | Steel plate butt-welding fittings |
| JIS B2316 | Socket-welding pipe fittings |
How to Read JIS Grade Designations
The number after the letters is the minimum tensile strength in megapascals. STPG410 has a minimum tensile strength of 410 MPa, and STS480 has 480 MPa. The TP suffix in G3459 indicates pipe for piping service, and the preceding digits identify the stainless family, such as 304 and 316. When ordering, always state the standard number, the grade, the nominal size and the wall thickness series, because JIS pipes use their own outside-diameter and schedule systems.
Selection Points and Common Misconceptions
Do not confuse G3454 and G3455: both are pressure pipe standards, but G3455 STS is the higher-strength series for high-pressure service. G3452 SGP is not a pressure-rated product and must not be used where the design code requires STPG. JIS G3458 alloy pipes are not interchangeable with stainless pipes, and G3459 stainless pipes are not rated by the carbon steel pressure tables. Flanges and fittings must be ordered to the matching JIS series, because JIS flange dimensions and pressure ratings differ from ASME dimensions.
FAQ
What is JIS G3452?
JIS G3452 covers carbon steel pipes for ordinary piping, designated SGP, used for water, gas, steam and air at low pressure in buildings and plants.
What is the difference between JIS G3454 and G3455?
G3454 STPG is carbon steel pipe for pressure service, while G3455 STS is the higher-strength series for high-pressure service.
What does STPG410 mean?
STPG is the grade prefix for pressure-service carbon steel pipe, and 410 is the minimum tensile strength in megapascals.
Which JIS standard covers stainless steel pipe?
JIS G3459 covers stainless steel pipes such as SUS304TP and SUS316TP, and JIS G3468 covers arc-welded large-diameter stainless pipe.
What is JIS B2220?
JIS B2220 is the steel pipe flange standard that defines the dimensions, facing and drilling of flanges used with JIS piping.
Are JIS flanges interchangeable with ASME flanges?
No. JIS flange dimensions, bolt circles and pressure ratings differ from ASME flanges, so the mating flange and gasket must be selected from the same standard.