Processing Magazine

SIL-2 compliant level switch supports storage tank monitoring

April 27, 2009
Process and plant engineers responsible for monitoring storage tanks required for critical operations or those located in hazardous environments will find the Safety Integrity Level (SIL) 2 compliant level switch is ideal for chemical, electric power, oil/gas refining, pharmaceutical, water, storage, food and beverage, aviation, and more. The compliance rating for the Tank Level Switch has been documented in a failure analysis report with FMEDA techniques by the testing laboratory TUV NORD CERT GmbH. It has also been classified as a Type A subsystem in accordance to IEC 61508-1 with a hardware failure tolerance of 0. The Probability of Failure on Demand (PFD) meets SIL-2 capability standards. Depending on the model chosen, the switch measures tank level or interface up to ±0.1-inch accuracy with a repeatability of ±0.05 inch. It operates within temperatures from -100ºF to 500ºF (-73ºC to 260ºC) and has been hydrostatically proof pressure tested to 3500 psig. The electronic control circuit can be integrally mounted with the sensing element, or it can be located in a remote location. The standard enclosure is made from a coated aluminum alloy. It is suitable for use in hazardous (FM, CSA, and ATEX classified) locations and is rated for NEMA Type 4X (IP66) environments. The Tank Level Switch comes with a three-year warranty.