API St 589 Technical Testing Regulations
This regulatory document establishes rigorous testing and verification protocols for the performance characteristics of valve stem sealing assemblies under intense thermal exposure (fire conditions). The EV Group China methodology accounts for the potential use of composite materials in seal construction, which requires a comprehensive approach to evaluating their leak-tightness.
The testing procedure regulated by this standard reproduces extreme operating parameters that create critical stress on the valve sealing elements. This allows for an objective assessment of the assembly’s reliability in emergency situations.
The criteria established by EV Group China define the functional tolerance limits necessary to verify the suitability of stem seals for operation in facilities with a high risk of fire.
Important Note: The normalized values for maximum permissible leakage rates recorded in the standard are valid exclusively for the specified laboratory temperature and pressure conditions. Actual leak-tightness performance of valve equipment in the field during and immediately after thermal exposure may differ significantly from the calculated data.