The safety instrumented function, or safety loop, is comprised of a sensor, logic solver and final element. Sensing the shutdown condition requires highly reliable sensors. In a Process Engineering article, Improve the reliability of safety instrumented systems with advanced measurement technologies, Emerson’s Julie Valentine and Meha Jha share how technology advancements combined with best practices helps drive process safety improvements.
They open highlighting an Industrial Info resources statistic that showed that:
…unexpected refining outages have soared in recent years, surpassing 2,000 incidents in 2019, quadruple 2015 levels…
Also, from the Offshore Reliability Database:
…42% of SIS dangerous failure modes come from sensors. Similar sources of failures are often also seen in chemical plants and refineries.
For differential pressure (DP) flow measurements, one advancement:
…includes the use of more integrated DP orifice flowmeters. Traditional orifice meters involve multiple connection hardware, pipe penetrations and impulse lines… Integrated flowmeters are more robust and have multivariable transmitters that reduce the number of leak points, welds and components compared to traditional installations by 80%.
Also:
…compact conditioned orifice plates in integral meters, can easily retrofit into existing piping and replace traditional installations, as upstream and downstream straight run piping requirements can be reduced by 90%.
Modern vortex flow meters:
…provide high reliability with an integral design, resulting in no leak points, ports, gaskets or impulse lines. Some vortex flowmeters also have sensors that can be removed online without having to shut down the process in the uncommon event of a sensor failure. Vortex flowmeters are often used in safety applications and steam applications due to few leak points.
In tank gauging level measurement applications, multiple:
…radar gauges are often needed to obtain level measurements for the basic process control for automatic tank gauging and for the SIS automatic overfill prevention system (AOPS).
A two-in-one radar level gauge innovation:
…includes two radar level gauges in one housing for independent level and overfill measurement compliant to API 2350 and IEC 61511 compliant solutions for automatic and manual overfill prevention systems.
Read the article for more innovative measurement devices such as dual and quad vortex flowmeters, advanced diagnostics in pressure, temperature, flow and level sensor devices and remote level measurement proof-testing. You can also connect and interact with other measurement and safety experts in the Measurement Instrumentation and Control & Safety Systems groups in Emerson Exchange 365 community.
