Regulatory Tug-of-War Rages in Calibration

The calibration trend Ed Shuler sees now is the push for reduced manpower in instrumentation and electrical (I&E) shops on unnecessary calibration.

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But counteracting that ambition for more efficient operations, “at the other end of the spectrum, regulatory issues, in general, are driving more calibration,” states the Fort Collins, Colo.-based senior applications engineer for controls vendor Honeywell Process Solutions’ ( high-performance-solutions DocuMint team.

In this tug-of-war, regulatory compliance may create calibration problems.  “Probably the best example comes from a pharmaceutical manufacturer. They require verification that their pH measurement is within specification at the beginning of every batch cycle,” explains Brian J. Dickson, vice president of field devices for vendor Invensys Process Systems (, Plano, Texas. “The system in use was slow to respond, creating as much as 18-hour delays to get the pH meter to meet the laboratory test.” A high-speed Invensys Dolphin probe and analyzer solved that, he notes.
Besides faster or improved instrumentation, though, what are the most used or most liked calibration-management strategies that companies use now? “Automated workforce management is very popular,” Dickson says. Using wireless technologies to integrate the system and generate work orders is becoming more popular, he adds. “These systems save time and input errors by using drag-and-drop technology.” There is no need to pull test documents or schedule the calibration route, he explains, because “this is done automatically.” He remarks that automated calibrators also find a place in plant-wide enterprise asset management strategies.

Solutions might also include technology such as Honeywell’s DocuMint, which Shuler describes as a “standard historian that integrates with a handheld documenting process calibrator (DPC).” For any calibration issues, the calibration database is typically built offline in a computer, he explains. That database identifies certain tags that, within a certain timeframe, need to be calibrated. “You would load the calibrations in the DPCs, then go out and perform the calibrations.” The DPCs record instrument accuracy before and after calibration. Back in the I&E shop, field data get downloaded into the test-result database for permanent storage in the historian. Then, when a regulatory auditor or inspector shows up, all the company needs to do is “click a button and produce the test results.”

End-users “want to avoid complex procedures and multiple handheld devices,” Dickson observes. “[And] devices must have intelligence in the calibration routines to warn the user if the calibration looks bad, and stop the user from making incorrect adjustments.” But he emphasizes that automating calibration processes isn’t about keeping workers out of the plant site. “Mobile workforce tools allow the workforce to be more efficient, while also providing more safety.”

Regulations motivate

Safety does drive calibrations, Shuler agrees. Noting that regulatory issues now motivate calibration more than process control, he says insurance concerns also compel more calibration. “For example, because of an explosion at a domestic petrochemical facility, causing several fatalities, the owner/operator’s insurance company required the company to install and get trained on the DocuMint calibration-management package,” he comments. “And they did that because they recognized their calibration recordkeeping was subpar.”

On the process operating side, however, industry has also tried the Wiebull continuous probability distribution to identify early failures, Shuler remarks. But applied to instruments, the late Swedish engineer Waloddi Weibull’s statistical tool hasn’t been as successful as it has been in other arenas, such as the electronics industry, Shuler says. So that has led to establishing regular and frequent test schedules.

Regardless of solution, calibration issues Shuler mentioned—reducing unnecessary calibrations vs. regulators requiring more—“crosses all industry groups: food, power, pharmaceuticals or any other industry running batch or continuous processes,” he asserts. And regulatory requirements for more frequent calibrations may override goals such as just-in-time (JIT) calibration.

C. Kenna Amos,, is an Automation World Contributing Editor.

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