EN 331-2015 pdf download.Manually operated ball valves and closed bottom taper plug valves for gas installations for buildings.
5.6 Durability
5.6.1 Endurance test
The test equipment shall be designed so that the valve can be tested without inducing any torsion or bending stress. The manual actuator shall be cycled from the fully closed stop position to the fully open stop position and back. The applied operating torque, at ambient temperature, shall not exceed the torque specified in 4.7.1, Table 7. The operating speed shall be (5 ± 1) cycles per minute. The test is carried out at ambient temperature using air as a medium, at nominal pressure and with a flow rate (5 ± 2) % of the rated flow rate specified in Table 6.
After the endurance test the sample is checked for external and internal leak-tightness at ambient temperature and at (60 ± 5) °C according to 5.2. After cooling to ambient temperature, the operating torque is measured according to 5.4.
5.6.2 ResIstance to low temperature
Prior to the endurance test in 5.6.1, the sample is maintained at a temperature of either —5°C or —20°C
(depending on class) for 9 h ± 3 h.
The sample is then subjected to a test pressure as specified in 5.2.1 and 5.2.2.
The operating torque is measured immediately after removal from the low temperature chamber in accordance with 5.4.
5.6.3 Salt spray resistance
This test shall be carried out on device N° 3 according to Table 10 following the requirements of
EN ISO 9227, for a neutral salt spray (NSS).
The device shall not be under pressure and shall be disconnected.
If it was designed by the manufacturer, the protection shall be positioned at the outlet of the device. The inlet of the device shall be closed by a cap.
The test chamber shall spray a saline solution having a mass concentration of (5 ± 0,5) % sodium chloride in distilled water.
The intensity of the spray shall be such that, for each 80 cm2 of horizontal collecting surface, (2 ± 1) ml of solution are collected per hour.
The test chamber shall be maintained at a temperature of (35 ± 1) C.
the flow measuring device indicates no flow. Measure the angle between the closed position and the “no flown position. The measured value shall be in accordance with 4.2.8.
5.8 Safeguard against overloading of the handle – Stop resistance
Apply the chosen operating torque x 1,5 times (±1 N.m) among the values of Table 7 at ambient temperature. Check the valve, after the torque is removed, visually for any deformation, cracking or failure of the mechanism.
6 Assessment and verification of constancy of performance – AVCP
6.1 General
The compliance of manually operated ball valves and closed bottom taper plug valves for gas installations for buildings with the requirements of this standard and with the performances declared by the manufacturer in the DoP shall be demonstrated by:
— determination of the product type;
— factory production control by the manufacturer, including product assessment.
The manufacturer shall always retain the overall control and shall have the necessary means to take responsibility for the conformity of the product with its declared performance(s).
6.2 Type testing
6.2.1 General
All performances related to characteristics included in this standard shall be determined when the manufacturer intends to declare the respective performances unless the standard gives provisions for declaring them without performing tests (e.g. use of previously existing data, CWFT and conventionally accepted performance).
Assessment previously performed in accordance with the provisions of this standard, may be taken into account provided that they were made to the same or a more rigorous test method, under the same AVCP system on the same product or products of similar design, construction and functionality, such that the results are applicable to the product In question.
NOTE I Same AVCP system means testing by an independent third party under the responsibility of a notified product certification body.
For the purposes of assessment, the manufacturer’s products may be grouped into families, where it is considered that the results for one or more characteristics from any one product within the family are representative for that same characteristic for all products within that same family.EN 331-2015 pdf download.