BS EN 60671:2011 PDF

1   Scope Where functional reliability is required by general safety standards, one aspect of demonstrating this reliability is testing performed on-line during plant operation or during plant shutdown in preparation for return to power operation. This standard lays down principles for testing I&C systems performing category A, B and C functions, per IEC 61226, during normal power operation and shutdown, so as to check the functional availability especially with regard to the detection of faults that could prevent the proper operation of the functions important to safety. It covers the possibility of testing at short intervals or continuous surveillance, as well as periodic testing at longer intervals. It also establishes basic rules for the design and application of the test equipment and its interface with the systems important to safety. Further, the effect of any test equipment failure on the reliability of the I&C systems is considered. Types of surveillance tests may include:

– self-tests for I&C equipment;

– test of a group of equipment or components to confirm properties that support the safety function (continuity, power availability , etc.);

– test based on information redundancy or comparison of control signatures (consistency checking for redundant sensors, CRC-...