BS EN 161-2002 pdf download.Automatic shut-off valves for gas burners and gas appliances.
7.10.4 When the flow rate changes in response to external electrical signals, it shall not, when tested to
8.10. overshoot in either direction while attaining the new flow rate by more than 20 % of the flow rate at that particular set point, or as declared by the manufacturer.
7.11 Closed position indicator switches
A closed position indicator switch shall indicate the closed position of the valve. The switch shall indicate closure when either:
— the flow rate Is equal to or less than 10% of the equivalent fully open flow rate at the same pressure difference; or
the closure member is within 1 mm of its closed position.
7.12 Durability
7.12.1 Elastomers in contact with gas
7.12.1.1 General
Elastomers in contact with gas (e.g. valve seals, 0-rings, diaphragms and lip seals) shall be homogeneous, free from porosity, inclusions, grit, blisters and other surface imperfections visible with the naked eye.
7.12.1.2 Resistance to lubricants
The resistance to lubricants of elastomers shall be checked by an immersion test in test oil No. 2 carried out according to 8.12.1.2. After this test, the change of mass shall be between -10% and +10%.
7.12.1.3 Resistance to gas
The resistance to gas of elastomers shall be checked by an mmerson test using n-pentane (minimum 98 %
by mass of n-pentane, estimated by gas chromatography) carried out according to 8.12.1.3. After this test,
the change of mass shall be between -15 % and +5 %.
7.12.2 Marking
Adhesive labels and all marking shall be resistant to abrasion, humidity and temperature and shall neither lift nor discolour such that the marking becomes illegible.
This requirement shall be verified by the test described in 8.12.2.
7.12.4 Resistance to scratching
Surfaces exclusively protected with paint shall withstand the scratch test of 8.12.6 before and after the humidity test of 8.12.7 without the ball penetrating the protective coating to expose bare metal.
7.12.5 Resistance to humidity
All parts including those with protected surfaces, (e.g. coated with paint or plating) shall withstand the humidity test of 8.12.7 without any signs of corrosion, lifting or blistering visible with the naked eye.
8 Methods of test
8.1 Test conditions
Unless otherwise specified, carry out all tests using air at (20 ± 5) °C at an ambient temperature of
(20 ± 5) °C.
Correct all measured values to the following reference conditions:
15 C, 1 013.25 mbar, dry.
8.2 Mounting position
Carry out all tests in the mounting position declared by the manufacturer. Where there are several declared mounting positions, carry out tests in the least favourable position.
8.3 Closing function
Energize the valve at the maximum rated voltage or current and at the maximum actuating pressure, if applicable. Slowly reduce the voltage or current to 15 % of the minimum rated value. Verify that the valve has closed.
Energize the valve at the maximum rated voltage or current and at the maximum actuating pressure, if applicable. Increase the voltage or current to 110% of the maximum rated value, keeping the actuating pressure, if any, unchanged. De-energize the valve and verify that it has closed. For a.c. valves, remove the voltage at the peak of the current waveform.
Energize the valve at the maximum rated voltage or current and at the maximum actuating pressure, if applicable. Reduce the voltage or current to a value between 15 % of the minimum rated value and 85 % of the maximum rated value, keeping the actuating pressure, if any, unchanged, De-energize the valve and verify that it has closed. Carry out this test at 3 different voltages or currents between 15 % of the minimum rated value and 85 % of the maximum rated value.
8.4 Closing force
This measurement is carried out in the ungreased condition.
Measure the minimum closing force over the travel of the closure member from the open position to the closed position.
Remove the spring(s) providing the dosing force from the valve and measure the maximum force required to move the closure member from the open position to the closed position.
8.5 Delay time and opening time
Measure the time interval between energizing the valve and the start of the release of the closure member.
Measure the time interval between energizing the valve and the attainment of a flow rate equal to 80 % of the rated flow rate.
Carry out the tests under the following conditions, allowing the de-energized valve to reach thermal equilitxium before carrying out the tests:
– at 60 C (or at the maximum ambient temperature, if higher), at the maximum working pressure, at 110 % of the maximum rated voltage or current and at the maximum actuating pressure. ii applicable:
at 0 °C (or at the minimum ambient temperature. if lower), at a working pressure of 6 mbar, at 85 % of the minimum rated voltage or current and at the minimum actuating pressure, if applicable.
8.6 Closing time
Measure the time interval between de-energizing the valve and the closure member attaining the closed position, under the following condtlons:
— at the maximum working pressure, at a pressure difference declared by the manufacturer, at 110 % of the maximum rated voltage or current and at the maximum actuating pressure, if applicable:
at a working pressure of 6 mbar, at the minimum pressure difference declared by the manufacturer, at 110 % of the maximum rated voltage or current and at the maximum actuating pressure. if applicable.
8.7 Leak-tIghtness
8.7.1 General
Use a method that gives reproducible results, for example;BS EN 161-2002 pdf download.