The gate valve fire test is a special test that simulates a fire environment to verify the valve's ability to maintain tightness and structural integrity at high temperatures, preventing the fire from being aggravated by medium leakage caused by valve failure. This test is one of the mandatory certification items for valves in high-risk industries such as petroleum and chemical industries.
1. Test standards and scope of application
| Standard | Core Requirements | Applicable valve type |
|---|---|---|
| API 6FA | The test temperature is 650℃ for 30 minutes. After cooling, it needs to pass the 1.5 times rated pressure strength test and 1.1 times pressure sealing test. | American Standard Gate Valve (like: ANSI Class 150-2500) |
| GB/T26481 | After the fire test, the leakage rate is ≤40 bubbles/minute, and the torque increase of the opening and closing operation is ≤30%. | National standard gate valve(PN10-PN420) |
| ISO 10497 | Hard seal valves allow a small amount of leakage (≤10mL/min), soft seal valves require zero leakage | International general metal hard seal gate valve |
2. Core test process
Pretreatment stage
Install the valve in the combustion furnace in the closed state, connect the pressure source (water/nitrogen) and pressurize it to the rated pressure;
Configure the thermocouple to monitor the temperature of key parts such as the valve body and valve stem in real time (error ±5℃).
Fire resistance test
Use a propane burner to heat the valve completely, raise the temperature to 650℃ within 30 minutes and maintain stable combustion;
Record the leakage during combustion (soft seal valves must be ≤0.01% DN) and the deformation of the valve body.
Post-performance verification
After cooling, perform low-pressure sealing test (0.6MPa) and high-pressure strength test (1.5 times rated pressure), and no leakage for 3 minutes is qualified;
Manually operate the valve to open and close 5 times throughout the process to verify the flexibility of the action.
3. Key judgment indicators
| Test items | Eligibility criteria | Corresponding detection method |
|---|---|---|
| External leakage | Hard seal ≤10mL/min; soft seal zero leakage (ISO 10497) | Bubble counting method/flow meter measurement |
| Structural strength | After combustion, the shell has no cracks and the pressure deformation is ≤0.2% | Strain gauge monitoring + visual inspection |
| Operational performance | Opening and closing torque increase ≤ 30%, no lag in movement | Torque wrench actual measurement + feel evaluation |
4. Application and selection recommendations
Mandatory configuration for high-risk scenarios: refinery flare systems, LNG storage and transportation pipelines and other high-risk areas for fire; Material optimization direction: Inconel 718 alloy is preferred for valve stems, and tungsten carbide hard alloy cladding structure is used for valve seats; Certification extension rules: DN100 gate valve test can cover DN200 products of the same model, and the pressure level coverage follows the 2:1 principle.
