Performance testing requirements
1. When the valve is manufactured in batches with a certain specification, the following performance tests should be entrusted to the official organizations: 1) the opening and closing moment of the valve under the working pressure condition; 2) the detection of the flow resistance coefficient of the valve under the condition of pipeline water delivery.
2. Valves should be inspected before they leave the factory as follows: 1. Valve body should be inspected under internal pressure twice the working pressure of the valve when the valve is open; 2. Valves under closed condition bear 11 times the working pressure of the valve on both sides respectively, without leakage; but for metal-sealed butterfly valves, the leakage value is not greater than the relevant requirements.