Valve Standards Comparison: API, ASME/ANSI, ISO, DIN, JIS & GB Explained
Quick Answer
Valve standards differ by region and issuing body. In North America, ASME B16.34 (referenced alongside API 600, API 608, and API 6D) governs pressure-temperature ratings and key dimensions. Europe follows EN and ISO (EN 12516, EN 558, EN 1092). Germany uses DIN, Japan uses JIS, and China uses GB. The practical differences appear in three areas: pressure-temperature ratings, face-to-face dimensions, and flange connection standards.
Why Valve Standards Matter
A valve is rarely specified in isolation. It must bolt into an existing pipeline, match a flange, and satisfy a pressure-temperature envelope defined by the governing standard. Specifying the wrong standard leads to mismatched face-to-face dimensions, incompatible flanges, or an under-rated body. For procurement and engineering teams, understanding the major standards is the first step to a correct specification.
The Major Valve Standards Bodies
| Standard Family | Region | Issuing Body | Representative Valve Standards |
|---|---|---|---|
| ASME / ANSI | USA, North America | ASME (formerly ANSI) | B16.34 (pressure-temperature ratings), B16.10 (face-to-face), B16.5 (flanges) |
| API | USA, global oil and gas | American Petroleum Institute | API 600 (gate), API 608 (ball), API 609 (butterfly), API 6D (pipeline) |
| ISO | International | International Organization for Standardization | ISO 5208 (shell testing), ISO 5752 (face-to-face), ISO 10434 (bolted bonnet) |
| EN / DIN | Europe, Germany | CEN / DIN | EN 12516 (shell strength), EN 558 (face-to-face), EN 1092 (flanges) |
| JIS | Japan | Japanese Industrial Standards | JIS B 2003 (testing), JIS B 2210 (flanges) |
| GB | China | Standardization Administration of China | GB/T 12224 (ratings), GB/T 12221 (face-to-face), GB/T 9113 (flanges) |
Pressure-Temperature Ratings: The ASME B16.34 Class System
ASME B16.34 defines valve bodies by Class — Class 150, 300, 600, 900, 1500, and 2500. Each class carries a maximum allowable working pressure that decreases as temperature rises. The table below shows representative allowable pressures for Group 1.1 carbon steel (such as A105 or WCB) in psig.
| Temperature (deg F) | Class 150 | Class 300 | Class 600 | Class 900 | Class 1500 | Class 2500 |
|---|---|---|---|---|---|---|
| 100 | 285 | 740 | 1480 | 2220 | 3705 | 6170 |
| 200 | 260 | 675 | 1350 | 2025 | 3375 | 5625 |
| 300 | 230 | 655 | 1310 | 1965 | 3275 | 5460 |
| 400 | 200 | 635 | 1270 | 1905 | 3180 | 5300 |
| 500 | 170 | 600 | 1200 | 1800 | 3000 | 5000 |
| 600 | 140 | 550 | 1100 | 1650 | 2750 | 4585 |
| 650 | 125 | 535 | 1070 | 1605 | 2675 | 4460 |
| 700 | 110 | 500 | 1000 | 1500 | 2500 | 4165 |
| 750 | 95 | 450 | 900 | 1350 | 2250 | 3750 |
| 800 | 80 | 370 | 740 | 1110 | 1850 | 3100 |
Note: These values are representative of ASME B16.34 Group 1.1 carbon steel and are provided for comparison. Actual allowable pressures depend on the material group and must be verified against the current edition of the standard.
Face-to-Face Dimensions
Face-to-face (FTF) is the distance between the two flange faces of a valve. It is standardized so a valve can be installed between pipe spools without field modification. The main families are:
- ASME B16.10 — North American generic FTF for steel valves (short and long patterns).
- API 6D — pipeline valves, specific FTF dimensions.
- EN 558 — European, organized into Series 1 (DIN 3202 F1), Series 2 (F2), and Series 3 (F3).
- ISO 5752 — international, aligned with EN 558.
- GB/T 12221 — China, mapped to ISO 5752.
A common mistake is assuming an API 6D valve and an EN 558 Series 1 valve of the same nominal size have the same FTF. They often do not, and the valve will not fit.
Flange Standards
Flanges must match in diameter, bolt circle, number of bolts, and facing. The major systems are:
| Standard | Range | Notes |
|---|---|---|
| ASME B16.5 | NPS 1/2 to 24, Class 150 to 2500 | Raised face most common |
| ASME B16.47 | NPS 26 to 60 | Series A (MSS) and Series B (API) |
| EN 1092-1 | PN 2.5 to PN 100 | Flange types 01 to 05 |
| JIS B 2210 | 5K to 20K | Different bore and bolt circle |
| GB/T 9113 | PN series | Aligned with EN 1092 |
How to Select the Right Standard
- North American oil and gas: API design standards with ASME B16.34 ratings and ASME B16.5 or B16.47 flanges.
- European process plant: EN and ISO standards with EN 1092 flanges.
- Spare or retrofit valves: match the standard already installed (FTF and flange), not the newer one.
- Export equipment: confirm the destination market requirement before specifying.
Common Specification Pitfalls
- Treating Class 150 as equal to PN 20. They are close at ambient temperature but not identical, and diverge at higher temperatures.
- Mixing face-to-face patterns between suppliers.
- Bolting a DIN (EN 1092) flange to an ASME (B16.5) nozzle without an adapter.
References
This guide references public standard families including ASME B16.34, ASME B16.10, ASME B16.5, API 600, API 608, API 6D, EN 12516, EN 558, EN 1092, ISO 5752, ISO 5208, JIS B 2003, JIS B 2210, GB/T 12224, GB/T 12221, and GB/T 9113. Always consult the current edition and the valve manufacturer data sheet for project-specific ratings.
For dimensionally verified specifications across more than 1,000 valve products and 90 plus brands, see the ValveSpecs Pro specification database. For a detailed pressure-temperature rating chart across material groups, see our valve pressure-temperature rating reference.
Frequently Asked Questions
Is Class 150 the same as PN 20?
No. Although they are sometimes loosely equated, Class 150 (ASME B16.34) and PN 20 (EN) have different pressure-temperature ratings. At ambient temperature Class 150 allows about 285 psig while PN 20 allows about 290 psig, close but not identical, and the difference grows at elevated temperatures. Do not assume they are interchangeable without checking both ratings.
Which standard should I use for a pipeline valve?
Pipeline and oil and gas applications typically use API 6D for design and ASME B16.34 for shell and pressure-temperature ratings, with flanges to ASME B16.5 or ASME B16.47. The exact standard should follow the project piping specification.
Can I install a DIN valve on an ASME flange?
Not directly. DIN (EN 1092) and ASME (B16.5) flanges have different bolt circles, facing profiles, and pressure ratings. Use a compatible adapter or specify matching flanges on both sides of the joint.
What does ASME B16.34 cover?
ASME B16.34 covers pressure-temperature ratings, dimensions, tolerances, materials, and testing for steel valves. It is the primary reference for valve body and bonnet ratings in North America.
How do I confirm a valve design standard from its specification?
Look up the valve by tag or model in a specification database, which lists the design standard, pressure class, and flange type alongside dimensional data. This avoids relying on the nameplate alone.