API 598 is the core inspection and testing standard in the field of valves, and its core uses can be summarised as follows:
1. The core positioning
General test specification: API 598 specifies the factory inspection, pressure test and sealing performance assessment methods for industrial valves, applicable to a wide range of valve types (e.g., ball valves, gate valves, globe valves, etc.).
Standardised process: By unifying the test requirements (such as test pressure, media, holding time, etc.), to ensure that the valve meets the design performance and leakage control indicators before delivery.
2. The applicable valve types
metal and non-metallic sealing valves
covers metal-to-metal sealing (such as cast steel, stainless steel valves) and non-metallic sealing (such as elastomeric sealing ball valves) leakage detection.
Valves for special conditions
support for low-temperature valves before the test of deep cold treatment verification (such as liquid nitrogen cooling after the sealing performance test).
3. Typical test items
shell strength test
using liquid media (such as water) pressurised to 1.5 times the nominal pressure of the valve, to verify the structural integrity of the valve body.
Sealing performance test
Low-pressure sealing: the use of gaseous media (such as air) in the 0.5-0.7 MPa pressure to detect leakage, applicable to conventional working conditions.
High-pressure sealing: metal-sealed valves using liquid media (such as paraffin) pressurised to 1.1 times the nominal pressure, allowing a limited leakage rate (non-metallic seals need to be zero leakage).
Operational flexibility check
verify the smoothness of the valve opening and closing process and stem sealing effect.
4. The industry application scenarios
oil and gas and chemical industry
As a supplement to API 6D and other standards of the test method, used for the mandatory acceptance of main pipeline valves before leaving the factory.
Conventional industrial field
Independently applied to non-oil and gas industry (such as power, water treatment) for general valve quality control.
International project compliance
is often used in conjunction with ASME B16.34 or ISO 5208 to meet the standardisation needs of cross-border project tendering.
5. Expanded Applications
Repair and Retrofit Verification: Assess the reliability of repaired valves through repetitive testing.
Sealing class classification: quantitative classification of valve sealing performance level based on leakage rate (such as for flammable and explosive media, high sealing requirements of the scene).
Note: API 598 test procedures (such as holding time, media selection) need to be adjusted in conjunction with the specific valve type and operating conditions, manufacturers and users can add special requirements through the Agreement