with Fail-in-place I/P Valve Positioner
Product Performance: evaluation for an electrical to pneumatic (I/P) digital valve positioner involved in a boiler furnace explosion due to insufficient combustion air. The fail-in-place positioner closed the inlet air damper following a lightning strike that rendered it inoperative. The forensic analysis of the Safety Instrumented System (SIS) involved failsafe and fault tolerant concepts for a damaged device. The positioner's damage was unrelated to the specific malfunction (loss of signal) that was addressed in its failsafe design.
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