Fugitive Emission Standards
ISO 15848
The ISO 15848 standard specifies the measurement, testing, and evaluation procedures for fugitive emissions from industrial valves. This standard is divided into two parts. ISO 15848-1 defines a classification system and evaluation procedure for valve type testing, while ISO 15848-2 specifies valve manufacturers' acceptance testing of valve products.
TA-LUFT (VDI 2440)
The German fugitive emission control law TA-Luft VDI2440 defines leakage rates and testing methods.
VDI2200, VDI2440, and TA-LUFT (Flange Connection)
According to TA-Luft and VDI 2440, flange connections must meet a maximum leakage rate of 10-4 mbar x I (s x m) under a test pressure of 1 bar. VDI 2200 specifies the selection, calculation, design, installation, and testing process of bolted flange connections, with allowable leakage rates referring to VDI 2440. VDI 2200 also specifies safety testing for gasket burst. This test is conducted to avoid sudden leakage caused by seal explosion.
CLEAN AIR ACT
Clean Air Act specifies the maximum allowable leakage class for flange connections, valves, pumps, and mixers in the United States. Leakage testing must be carried out according to EPAMethod21 (sniffing method), with the testing medium being methane.
API 622
The second edition of API 622 is an international performance test for packing materials, which includes factors such as temperature, pressure, thermal cycling, and mechanical cycling. The second edition of API 622 specifies 1510 mechanical cycles and 5 thermal cycles. High-temperature testing is performed from room temperature to 260 °C (500 °F) and pressure rating from 0 to 600 psi (0-41bar). When the test medium is methane, the allowable leakage class is 100 ppm.
API 624
The first version is the fugitive emission test of the valve type with graphite packing and lifting stem. This standard includes the up and down movement and rotational movement of the valve stem, with a maximum diameter of 24in. The testing process requires 310 mechanical cycles and 3 thermal cycles at a temperature of 260 °C (500 °F). The maximum allowable leakage rate is 100 ppm. The valve packing to be tested must first be tested in accordance with API 622, and the packing must meet the requirements for use at -29 °C to 538 °C (-20 °F to 1000 °F).
ISO 15848 Sealing Class
Class | Measured Leakage Rate | Remarks |
A (only helium) | ≤10-6 mg/(s x m) | In general, bellows sealed valves or 90° rotary valves with equivalent stem seals can achieve this class |
B | ≤10-4 mg/(s x m) | In general, valves with PTFE packing or elastic (rubber) sealed stem can achieve this class |
C | ≤10-2 mg/(s x m) | In general, valves with flexible graphite packing can achieve this class |
VDI2440 specifies the maximum leakage rate of hazardous volatile organic compounds from valves
Temperature | Measured Leakage Rate |
<250℃ | ≤10-4 mbar x I/(s x m) |
≥250℃ | ≤10-2 mbar x I/(s x m) |