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SEP-OCT 2017

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44 INTECH SEPTEMBER/OCTOBER 2017 WWW.ISA.ORG A ccurate, reliable, and repeat- able operation of monitoring and control loops in industrial automation and control systems (IAC Ss) is vital to maintaining the safety and re- liability of a production facility. Where repeatable measurements take place in the monitoring or control of a fa - cility, the measuring instruments and test equipment must have repeatable outputs. A well-planned calibration program, correctly implemented and maintained, directly contributes to achieving the desired operation. A new recommended practice (RP), ISA-RP105.00.01-2017, Management of a Calibration Program for Industrial Au- tomation and Control Systems, sets forth a basic framework for developing and maintaining a consistent calibration pro- gram for IACSs—including instrumenta- tion used in safety instrumented systems. It provides guidance on methodologies for calibration of an IACS by consider- ing the accuracy required by the process of each loop and, if necessary, adjusting loop components to achieve the desired loop or component accuracy. The need for the guidelines was identi- fied by former ISA President Leo Staples, senior manager, utility operational com- pliance, OG&E, since retired, based on a highly successful calibration program he developed. The ISA105 committee determined that the format of an RP, which gives recommended guidelines, as opposed to a standard with mandatory requirements, would enable users from multiple industries and applications to decide how to apply the practices most effectively for their specific needs. Importance of a calibration program Without a calibration program, mainte- nance of control, indication, and analyti- cal devices and systems often occurs only when the error in reading is large enough to be obvious to facilities personnel. Operations and maintenance personnel routinely make decisions based on these devices. A faulty indication on such a de vice could lead to the release of energy or another unsafe action. In contrast, a well-planned and im- plemented calibration program estab- lishes periodic assessments of loop/ component performance over time. Data acquired during these assess - ments not only helps establish future calibration intervals, but is critical for the allocation of capital and operational resources. Clearly defined policy and procedures support the efforts of main - tenance planners to schedule adequate labor and equipment for calibration both during and between facility out - ages. Following established calibration procedures and using correct equipment reduces the likelihood of human errors due to incorrect practices, prevents act - ing on incorrect information, ensures the desired results of the calibration efforts, and promotes the correct operation of an IACS. Further, targeted reduction or increase in calibration activities based upon the assessment of data derived from an instrument asset management calibration program can both reduce maintenance costs and improve reliabil - ity and safety. The new RP is a baseline definition and model of a quality management system that can be used to implement and main- tain a calibration program for an IACS. It covers topics including: • planning a calibration program—en- compassing required loop tolerances, confirmation intervals, and calibra - tion personnel, equipment, proce- dures, and record systems • verifying loop and component perfor- mance • managing the program Key concepts of the RP include: • the importance of a well-planned cali- bration program to facility operation safety and desired operation • the importance of monitoring the calibration program implementation and making corrections/improvements when necessary • calibration of a loop rather than the more common focus on field instru- ments only • setting reasonable goals for the per- formance of each loop (i.e., loop tolerance) rather than just using the rated accuracy of the field instrument • the difference between test equip- ment (which is used to check the operation of a loop/component) and calibration equipment (which is used to adjust a component) • instrumentation based on newer technology (such as "smart" devices), which is more accurate and more sta- ble than devices based on older tech- nology, requiring less frequent cali- bration monitoring but more accurate calibration equipment This approach to calibration has proven successful when users adhered to the concepts set forth in these guidelines, giving their organizations the full benefits of a standardized ap - proach to calibration. For information on viewing or obtain - ing ISA-RP105.00.01-2017, visit www.isa. org/findstandards. For information on the ISA105 committee, Commissioning, Loop Checks, and Factory & Site Acceptance/ Integration Tests for Industrial Automa- tion Systems, contact Charley Robinson, ISA Standards, crobinson@isa.org. n ABOUT THE AUTHOR Jim Federlein, PE (jim.federlein@ gmail.com) is the chair of ISA105 and director of the ISA Standards & Practices Board. He is the principal at Federlein & Associates, LLC. New ISA guidelines for managing a calibration program By Jim Federlein, PE New Benchmarks & Metrics | standards Send it to idea@isa.org Have an idea for an ISA standard, book, training course, conference topic, or other product or service?

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