BS EN 13922:2020 pdf free download – Tanks for transport of dangerous goods一 Service equipment for tanks一Overfill prevention systems for liquid fuels.
7 Testing
7.1 General
Two different forms of tests shall be performed on overfill prevention systems. The type tests which are carried out on two sample production units, and the production tests which shall be performed upon all production items by the manufacturer. To ensure cross-compatibility, each part of a overfill prevention system shall be tested. When testing sensor/sensor circuits, the test shall be performed with the specified maximum number of sensing devices connected.
Calibrated standard test devices shall be used to provide the specified interface signals. Type tests shall additionally prove the operation of the overfill prevention system at the specified tolerance limits. Test liquid shall be diesel according to EN 590 with the exception of the pressure test according to 7.2.5.
7.2 Type tests
7.2.1 General
Type tests shall include:
— performance testing;
— electromagnetic compatibility (EMC) tests;
— fail safe testing.
7.2.2 Performance tests
Performance tests shall be conducted as outlined in Annex A (Tables A.11 to A.15).
7.2.3 Electromagnetic compatibility (EMC) test
The sensor and the overfill prevention controller shall be tested separately, and in addition in a simulated installation according to:
— EN 61000-6-4 for emission;
— Performance Criterion A according to EN 6 1000-4-3 for immunity.
7.2.4 Fail safe testing
The fail safe operation of the overfill prevention system shall be verified as follows:
— failure of any single component, in short circuit or open circuit state, in the controller or in the sensor shall result in non-permissive signal or correct operation of the overfill prevention system; this may be verified by conducting a test or by conducting a circuit analysis;
— with the exception of the diagnostic line any opens or shorts in wiring to the sensors shall result in non-permissive signal;
— power supply failure shall result in a non-permissive signal;
— failure of any functional component of a compatible sensor shall result in non-permissive signal or correct operation of the system; this may be verified by conducting a test or conducting a design analysis.
7.2.5 Pressure test
7.2.5.1 General
This test shall be performed to demonstrate that the sensor, once installed within the tank compartment, shall be pressure and leak tight.
The sensor shall be installed in a test rig that correctly simulates the fixing of the assembly to the tank shell or manhole cover assembly. The tests shall be performed at ambient temperature conditions. A minimum of two production samples of each model type shall be tested to demonstrate the performance and mechanical strength of the design.
NOTE Devices having one design, size and pressure rating are considered to be of the one model type irrespective of length.
7.2.5.2 Procedure
With the sensor installed in the test rig, the internal pressure of the test rig shall be increased to the test pressure. Test liquid shall be water. Once stabilized, with the pressure source isolated, wait for 5 mm and then inspect the external and internal surface of the sensor for leaks.