Eight Common Pyrometry Mistakes That Cost Companies Thousands — and How to Avoid Them

From aerospace to pharmaceutical, many industries rely on furnaces and ovens to dry, cure, or bake materials, parts, components and coatings. Precise measurements of furnace temperatures help to ensure safe, dependable products that meet quality standards and customer expectations.

Any measurement device, such as the sensors used to measure oven temperature, will become less accurate over time. Faulty furnace temperature readings could lead to improper or incomplete drying, curing or baking (hardening) and compromise the quality and safety of the product.

Routine calibration of industrial ovens helps to ensure that equipment operates at the required temperature for the process, heat is distributed evenly, and temperature monitoring is accurate, so manufacturers produce the product they intended.

Common (and Costly) Pyrometry Mistakes

The ability to accurately measure high temperatures — a field known as pyrometry — is critical to the reliability of heat-treating and other industrial processes. Readings that are even a few degrees off could lead to scrapped batches, unplanned downtime, or product recall, with costs ringing up to hundreds of thousands of dollars, or more.

Below are eight common pyrometry mistakes and best practices to avoid them.

1. Neglecting Care, Maintenance & Calibration
   Like any mechanical equipment, furnace temperature sensors (thermocouples) will drift from specifications and become less accurate with repeated use, especially if they are not routinely maintained and calibrated. Some companies choose to defer maintenance or calibration in an effort to avoid downtime.

• • Best Practice: Establish and follow a strict calibration and maintenance schedule to identify minor issues before they escalate into costly mistakes. If a thermocouple is designed with a limited service life, replace it according to manufacturer guidelines.

2. Using the Wrong Type of Thermocouple
   The type of thermocouple needed varies depending on the application, temperature range, and operating environment. If a manufacturer does not use the correct type, the device is likely to produce inaccurate temperature readings or fail prematurely.

• • Best Practice: Ensure that your facility only uses sensors designed for your specific application and environment. Follow manufacturer guidelines and operate the thermocouple only within its defined safe operating limits.

4. Neglecting Controller & Instrument Calibration
   Even if your thermocouple is perfectly calibrated, an inaccurate temperature controller or recorder, or damaged extension wire, can lead to incorrect readings.

• • Best Practice: Create a comprehensive and proactive pyrometry program that includes calibration of controllers, indicators, recorders, and other related instrumentation.

5. Poor Sensor Placement
   Proper placement of the thermocouple is critical because the furnace controller will only measure the temperature where the thermocouple is located. If the sensor is located too close to heating elements or too far from the critical work zone, the readings may not be representative of oven temperature across the manufacturing process.

• • Best Practice: Consider thermocouple placement when evaluating temperature readings and ensure that maintenance personnel are trained on proper thermocouple handling and installation.

6. Failure to Perform Temperature Uniformity Surveys (TUS)
   TUS testing helps to detect hot and cold spots in furnaces. Failure to perform routine TUS testing could lead to improper heat treatment, non-compliances, inconsistent hardness, and other issues.

• • Best Practice: Be sure your pyrometry program includes regularly scheduled Temperature Uniformity Surveys.

8. Noncompliance with Industry Standards & Regulations
   In many industries, such as aerospace, strict regulations are in place to verify compliance. Detailed documentation may be required, such as records of furnace maintenance and temperature, calibration certifications, and sensor replacement history. Noncompliance can lead to costly corrective actions, failed audits, and loss of customer contracts.

• • Best Practice: Strictly follow all applicable industry standards and customer requirements for each part or process. Maintain meticulous records of all oven calibration and maintenance activities.

By taking steps to avoid these common pyrometry pitfalls, manufacturers can reduce costs, avoid compliance issues, and maybe even stay one step ahead of the competition.Top of Form And Industrial Inspection & Analysis (IIA) is here to help.

Precision Pyrometry from IIA

As one of North America’s leading providers, IIA offers a wide range of precision Pyrometry Testing & Oven Calibration Services to ensure that industrial ovens operate within defined parameters. Our comprehensive pyrometry services include System Accuracy Tests (SAT) to confirm temperature control system readings and Temperature Uniformity Surveys (TUS) that assess the consistency of temperatures in qualified work zones, as well as operating temperature ranges.

Our team has a full understanding of all regulatory requirements for oven calibration and pyrometry, including standards outlined in AMS2750 and the National Aerospace and Defense Contractors Accreditation Program (NADCAP). All calibrations are traceable to the National Institute of Science and Technology (NIST) and comply with ISO/IEC 17025.

Our mobile calibration technicians are ready to serve all your plant's calibration needs — from wireless temperature probes and gauges to entire furnaces. In the field and in the lab, IIA is committed to providing a fast turnaround on calibration jobs to minimize downtime and disruptions.

A Proactive Approach to Pyrometry

Without oven calibration, there is greater risk of product defects, equipment malfunctions, customer complaints, safety hazards, and lost revenue. In light of the ripple effect a temperature measurement deviation can have, it’s important to approach pyrometry as more than simply a maintenance issue. A robust pyrometry program will reflect engineering, production, maintenance, and quality assurance perspectives.

Even seemingly small errors pyrometry errors can lead to surprisingly costly consequences, so don’t put oven care and calibration on the back burner. By taking a proactive approach to pyrometry, your company could potentially save thousands of dollars and keep customers coming back for more. 

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“IIA has been a trusted partner for over a decade. They are our go-to team for all our pyrometry needs.”

 - Major Aerospace Component Manufacturing Company