Chinese Valve Model Numbers Decoded: The GB/T 32808 Coding System

Why This Matters for International Buyers

If you procure valves from Chinese manufacturers, you will receive quotations full of codes like Z41H-16C, Q941F-25P or D371X-10. These are not proprietary part numbers. They are a structured national coding system, and every character carries a specific engineering meaning.

Learning to read them takes about ten minutes and prevents a category of expensive mistakes: ordering a rubber-seated valve for a steam line, or a PN16 body where the project specification demands Class 150.

The Governing Standard

Chinese valve model numbers are built according to GB/T 32808-2016, "Valves - Model Compiling Method" (阀门型号编制方法), issued by the Standardization Administration of China. It replaced the older industry standard JB/T 308, which is still occasionally seen on legacy drawings and older catalogues.

The standard covers more than twenty valve categories, including special-service designations for oxygen service and hydroprocessing units.

The Seven-Unit Structure

A model number is assembled from seven units in fixed order:

Written out: Type + Actuation + Connection + Structure + Seat material — Pressure + Body material

Unit 1: Valve Type Code

The letter is derived from the Chinese pinyin initial of the valve type.

Prefix letters may be added for additional functions, for example D for cryogenic service and F for fire-safe designs.

Unit 2: Actuation Method Code

Three rules catch people out:

• A handwheel directly on the stem is omitted. No digit in position two means manual operation.
• Pneumatic and hydraulic actuators add a letter for fail position: 6K or 7K for normally open, 6B or 7B for normally closed.
• Explosion-proof electric actuators are written 9B. A pneumatic actuator with manual override appears as 6s.

Unit 3: End Connection Code

The code always describes the inlet end connection.

Unit 4: Structural Form Code

This digit is defined separately for each valve category. Gate valves use the following:

For ball valves, 1 is a floating ball straight-through design and 7 is a trunnion-mounted three-way design. For butterfly valves, 1 is concentric and 3 is single-offset.

Unit 5: Seat or Lining Material Code

Two rules govern this unit:

1. When the two sealing faces are different materials, the code reflects the softer material.
2. When the seat is machined directly into the body with no separate seat ring, the code is W.

Unit 6: Pressure Rating Code

This unit follows the hyphen.

• Metric ratings: nominal pressure in MPa multiplied by ten. So 16 means PN16 (1.6 MPa), 25 means PN25 (2.5 MPa), 320 means PN320 (32 MPa).
• ASME ratings: written directly as Class 150 or CL300.
• Temperature-qualified ratings: for high-temperature service the code carries both values, for example P54100 indicating 540 degrees C at 10 MPa.

Unit 7: Body Material Code

The body material code is omitted for grey cast iron at PN 1.6 MPa and below, and for carbon steel in some low-pressure product lines. An absent final letter is therefore meaningful, not an error.

Worked Examples

Z41H-16C

Read as: a manually operated, flanged, rising-stem wedge gate valve with 13Cr seats, PN16, carbon steel body.

Q941F-25P

Electric actuated (9), flanged (4), floating ball straight-through (1), PTFE seats (F), PN25, Cr-Ni stainless steel body. Typical of a remotely operated isolation valve in a chemical service line.

D371X-10

Worm gear operated (3), wafer type (7), concentric disc (1), rubber seat (X), PN10. The body material letter is absent, indicating cast iron at low pressure. A standard water and HVAC butterfly valve.

Z60Y-320

Manual, butt-weld ends (6), rising stem wedge elastic disc (0), hard alloy seat (Y), PN320 (32 MPa). A power-plant high-temperature, high-pressure gate valve.

Four Traps for Foreign Buyers

1. PN16 is not Class 150. The pressure unit uses the metric PN system. A PN16 body is rated 1.6 MPa, whereas Class 150 carbon steel is roughly 1.96 MPa at ambient. The flange drilling patterns also differ, so the two are not physically interchangeable. See our PN vs ASME Class comparison for the dimensional detail.

2. A missing digit is information. No actuation digit means handwheel. No body material letter usually means cast iron. Do not assume the supplier truncated the code.

3. The seat letter describes the weaker face. An H code does not guarantee both sealing faces are 13Cr; it guarantees the softer one is.

4. Codes describe design, not certification. A model number tells you the construction. It does not tell you whether the valve was tested to API 598 or GB/T 13927, or whether material certificates are available. Ask separately.

Cross-Checking a Quoted Model

The fastest verification path is to decode the model, then confirm the decoded attributes against the manufacturer datasheet. Body material, seat material and pressure rating for products across ninety-plus brands are catalogued in the ValveSpecs Pro database, which lets you sanity-check a quotation against comparable products before issuing a purchase order.

For the equivalence between Chinese GB standards and API or ASME design standards, see our GB vs API and ASME standards cross-reference.