A Calibration Service May Be Your Solution

A wide variety of instrument technologies, standards, installation conditions, and operating needs can make it difficult for industrial facilities to keep current with calibration needs. All images courtesy Endress+Hauser

Process-plant personnel struggling to keep up with instrument calibrations might find that a third-party provider meets their needs.

By Robert Jennings, Endress+Hauser

One reality that cuts across the entire range of processing plants and industries is the need for timely and proper instrument calibration. In addition to achieving efficient and safe operations, many must abide by regulations and standards that require constant instrument management. Doing so can be a tall order.

To perform and document instrument calibration, maintenance professionals must have specific training and specialized equipment. Depending on the facility, the instruments may consist of a variety of makes, models, sizes, and technologies—leaving it difficult to address every situation. For these and other reasons, many end users are seeking calibration assistance.

Like many other technical undertakings, instrument calibration is subject to the constraint triangle of fast—good—inexpensive. Usually, the tradeoff is between speed and cost because the “good” element is heavily specified by regulations and standards.

For clarity, the term “standards” can mean two different things with regards to instrumentation. One type of standard is a document published by a recognized authority, describing in detail the practices and procedures that must be followed. A second kind of standard, particular to calibration efforts, would be any precisely measured weight, process calibrator, or other similar reference that will be used to calibrate other instruments. These physical calibration working standards, or references, must be carefully and periodically maintained with traceability back to national/international standards.

Each instrument manufacturer may call for certain minimum requirements, and end-user production plants can demand even more restrictive means and methods. It is important to use service providers that are accredited and adhere to ISO/IEC17025 standards. Associated documentation must be meticulously created and maintained, along with a quality management system.

The nature of regulations is becoming more, rather than less, stringent, so end users must keep abreast of all requirements. This includes keeping calibration technician training up to date and finding a way to train replacements as the workforce changes and expertise gaps are created due to retirements.

Fully equipped instrument labs are the ideal environment for calibrating instruments when transporting them is possible.

When and Where

Time schedules for calibrations can vary widely, based on instrument types, applications, and end-user requirements. Some pharmaceutical companies will proactively calibrate instruments before every product run because losing a batch due to improper instrument operation could be a far greater expense.

Some companies won’t calibrate instrumentation until devices appear to drift or when they fail. Others use a calendar-based schedule to determine calibration intervals.

Many modern instrumentation and automation systems can generate an alert if an instrument is drifting out of calibration. This could be an alternative to running to failure or performing frequent calibrations. However, it is a challenge to replace a calibration without confidence in the measurement as proven by statistical data.

Continuous-processing industries, such as petrochemical and food and beverage, typically have few opportunities for downtime that allows calibration functions to be performed. This may add complication in the form of multiple redundant instruments so one can be calibrated at a time, demanding extra attention since the instruments must be handled while the process remains active.

Many of these industries schedule infrequent maintenance outages or turnarounds during which calibration work can be performed while the process is stopped for other major maintenance activities. Careful coordination is necessary to ensure the right materials and personnel are available to calibrate instruments during this brief window of opportunity. Occasionally, equipment failure will open an unexpected window of time during which work can be performed on associated out-of-service systems.

The “where” component can be just as involved as the “when.” A shop or laboratory, either on- or off-site, is usually an ideal and controlled environment stocked with everything needed to calibrate instruments. However, shop or lab calibrations require instrument removal, transport, and handling that introduces time delays, increases costs, and adds the risk of inadvertent damage.

These downsides can be offset by efficiencies gained when multiple field teams remove and reinstall instruments, enabling a small calibration team in a shop or lab to perform work quickly in bulk.

Instruments may also need to be calibrated in place because removal is impractical. For very quick turnarounds, the removal, transport, and replacement cycle may be unacceptably long. In those cases, an individual or calibration team must be ready for deployment to the field.

Calibration labs and highly trained technicians can support many instrumentation makes, models, and technologies, providing end users with an efficient option for staying in calibration.

Services Secure Scalability

Because calibration needs often come in waves, with relatively long periods of inactivity between them, it is very difficult for process plants to maintain the necessary staff, knowledge bae, and standards that assure a timely response. For this reason, plant personnel often find they can supplement or completely rely on instrument calibration vendors to provide specialized services for some or all of their metrology needs. These service providers are in the best position to deliver the required flexibility and scalability.

Depending on need, calibration support can be arranged to vary from half a day of service to a more long-term solution of having an embedded, full-time calibration technician.

Some calibration-service providers are strictly local or regional, but a provider with multiple regional facilities can provide distinct advantages. End users will always appreciate the availability of metrology technicians who are within a few hours travel time of their sites. Additionally, a geographically diverse presence means there are more technicians available to travel to sites during surge times. This also creates options for shipping units to a full-fledged lab for timely calibrations of large quantities of instruments.

Due to their scale, these larger service providers are also familiar with administrating large calibration-management programs, and they can often collaborate with end users to tailor their services to exactly what is needed. Some calibration service
providers may even be able to assist with process issues such as optimization and loop tuning, which relate to instrumentation but are outside the exact domain of calibration.

Every process plant requires some level of operational time sensitivity to ensure maximum productivity. These operations need properly calibrated instruments not only for efficiency, but often to meet regulatory requirements. Instrument calibration is a specialty activity, in some cases needed intermittently and unexpectedly, and often requiring a large number of specialized staff.

These and other issues can be addressed by engaging a calibration service provider to meet all or some of a plant’s metrology needs. This can allow a plant to maintain correct staffing levels for day-to-day operations, with the ability to quickly respond to any calibration challenges. EP

Robert Jennings is the Calibration and Repair Team Manager for Endress+Hauser Inc., which is headquartered in Greenwood, IN (us.endress.com). Jennings supports the company’s Gulf Coast Calibration & Service Center. He has grown the business by developing turn-key approaches for delivering timely and high-quality calibrations on projects of all sizes, freeing end users to focus on their core businesses.