EN 12266-1
EN 12266-1 Standard specifies requirements for tests, test procedures, and acceptance criteria for production testing of industrial valves made of metallic materials.
A.2 Shell strength, test reference
A.2.2 Test method
A.2.2.3 Test duration
The test pressure shall be maintained for a duration of no less than the periods specified in Table A.2.
Table A.2 - Minimum test duration for shell tests
| Nominal size | Minimum test duration | |
| Production test and acceptable test liquid or gas | Type test liquid or gas | |
| Up to DN50 | 15 S | 10 min |
| From DN 65 to DN 150 | 60 S | 10 min |
| DN 200 to DN 300 | 120 S | 10 min |
| DN 350 and above | 300 s | 10 min |
Every valve shall be proof tested unless it is in PED Category I, where a statistical proof test is permitted. Where production cycle times do not permit the test duration stated in Table A.2, each valve shall be tested for a duration which relates to the production cycle time, provided that a statistically valid series of tests shall be applied for the full time specified in Table A.2.
A.2.3 Acceptance criteria
The acceptance criteria shall be as follows:
a) If the lest fluid is a liquid, visually detectable leakage from any ex1emal surface of the shell is not permitted;
b) If the test fluid is a gas:
- No bubbles from any external surface of the shell and breaking the surface of the water are permitted;
- No continuous formation of bubbles is permitted when the valve is coated with leak detection fluid.
Unless otherwise specified in the appropriate product standard,leakage from the operating mechanism sealing is permitted at the shell test pressure,provided that there is no visually detectable leakage when the test pressure is 1.1 times the maximum allowable pressure at room temperature.
A.4 Seat tightness, test reference
A.4.2 Test method
A.4.2.3 The test pressure shall be maintained for a duration no less than the periods specified in Table A.4.
Table A.4 - Minimum test duration for seat tightness test
| Nominal size | Minimum test duration | |
| Production test and acceptance test | Type test | |
| Metal seated and soft seated valves | All valves | |
| Liquid or gas | Liquid or gas | |
| Up to DN50 | 15 S | 10 min |
| From DN 65 to DN 150 | 60 S | 10 min |
| DN 200 to DN 300 | 120 S | 10 min |
| DN 350 and above | 120 s | 10 min |
When the seal tightness is tested in a production line and the time of one production cycle is shorter than the production test time specified in Table A.4, the seat tightness shall be tested for the time of the production cycle. In this case, statistical process control tests shall be carried out confirming that all valves are capable of meeting the requirement of A.4.3.
A.4.3 Acceptance criteria
The choice of the rate A to G is specified in the relevant valve product standards.
The leakage rates measured during the specified test duration shall not exceed the rate specified in the corresponding product or performance standards. The acceptance criteria takes into account the uncertainty in the measurement. Leakage rates are given in Table A.5.
Tab A.5 - Maximum allowable seat leakage for each leakage rate
| Test fluid | Rate A | Rate B | Rate C | Rate D | Rate E | Rate F | Rate G |
| Liquid | No visually detectable leakage for the duration of the test | 0.01 x DN | 0.03 x DN | 0.1 x DN | 0.3 x DN | 1.0 x DN | 2.0 x DN |
| Gas | 0.3 x DN | 3.0 x DN | 30 x DN | 300 x DN | 3000 x DN | 6000 x DN |
NOTE 1: The leakage rates only apply when discharging to room temperature.
NOTE 2: Table A.1 shall be used to establish the equivalent DN number for those valves which are designated other than by DN.
NOTE 3: "No visually detectable leakage" means no visible weeping or information of drops or bubbles. If leakage rate measurements are carried out by automatic means, this should be qualified by the manufacturer's quality system.
