EN ISO 28921-2:2017

European foreword
Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Test conditions
5 Low temperature testing requirements
6 Information to be supplied by the purchaser
Annex A (normative) - Test procedure for type testing
        of valves at low temperature
Annex B (informative) - Information to be supplied
        by the purchaser
Annex C (informative) - Low-temperature type test record
Bibliography

ISO 28921-2:2015 specifies requirements for the type testing of isolating valves for low-temperature applications to verify the performance of valves at a low temperature from ? 50 °C down to ? 196 °C.NOTE Nominal sizes (DN), nominal pipe sizes (NPS), nominal pressure (PN) and Classes are covered in ISO 28921‑1.ISO 28921-2:2015 does not evaluate valve actuators unless they are integral part of the valve. Valves during testing can be operated manually or an actuator can be used during the testing. The effect of cold gas vapours during testing is taken into consideration in particular if the actuator is mounted directly over the test stand with the cold gases engulfing the actuator.ISO 28921-2:2015 does not apply to valves for cryogenic services, designed in accordance with ISO 21011, used with cryogenic vessels.