A manufacturer of vitamins and mineral supplements recently installed multiple Onset HOBO® temperature and humidity loggers in a climate-controlled storage facility to monitor seasonal temperature fluctuations and optimize product freshness.

To comply with strict FDA quality regulations and meet its own internal product quality standards, the company has implemented a seasonal temperature mapping program for its vitamin storage facilities throughout the country. Because many of its products are temperature and humidity sensitive, seasonal fluctuations like extreme summer heat or shifts in humidity can quickly compromise product quality. Soft gels, for example, are affected by higher temperatures, while hard tablets are greatly susceptible to humidity, absorbing moisture that makes them softer.

"We are dealing with organics here so they can go bad really fast," said an engineering project manager with the company. "When you have a storage facility with 30-foot ceilings and a warehouse racking system, heat can get trapped. You can't allow vast temperature swings, so we need to make sure our air handling units are sufficient to keep products within a temperature range of +/- 5° F, and a humidity range of +/- 3%."

A new approach to monitoring

To track warehouse environmental conditions in the past, the company had relied on a programmable sensor that was expensive and cumbersome. Looking for a more optimal solution, the engineering staff found Onset online and discovered the company's line of HOBO UX100 Series temperature and humidity loggers.

These matchbox-sized devices bridge the gap between traditional loggers, which typically don't have LCD displays and are limited in accuracy and memory, and larger, more expensive data loggers that are often difficult to use and maintain. The logger's built-in LCD screen makes it easy to check current temperature and relative humidity levels in real time, and provides indicators for logging status, battery use and memory consumption. The loggers work with Onset's HOBOware® software for graphing, analyzing and reporting of the environmental data.

Putting loggers to the test

In one warehouse temperature mapping project, engineers deployed multiple temperature and humidity data loggers in a 33,000 square-foot facility. Prior to installing the loggers, the staff tested the accuracy of the data loggers by putting them in an environmental chamber, plugging them in, setting the temperature and humidity ranges, and then monitoring to make sure the loggers stayed within those ranges.

Having passed the accuracy verification test, the loggers were configured with HOBOware software to measure and record temperature and humidity levels every 30 minutes on a 24/7 basis. Alarm notifications were set so warehouse staff could be immediately notified of problems. For example, if temperature or humidity conditions exceeded set thresholds, the event would trigger the logger to beep and display an alarm notification on the LCD.

In this particular project, the HOBO loggers were deployed in a vertical, column-like fashion at three different heights in the 30-foot high storage area. Loggers were placed at the top (25 ft.), middle (15 ft.) and bottom (1 ft.) of storage racks, and, where possible, mounted near air supply and returns. Data were logged for a period of three weeks - the manufacturer's standard duration for temperature mapping - and then offloaded to a computer for graphing and analysis.

Leveraging the data

At the conclusion of the three-week monitoring period, staff engineers were able to easily create graphs of the temperature/humidity profiles and incorporate them into slide presentations to update the company's leadership team. Detailed reports and high-quality visuals help the engineering team to make recommendations on any issues.

"If we find out the temperature or humidity has gone out of range, we will go to the HVAC folks and have the control system adjusted so there is more air supply in and less air supply out," said one of the engineers. "Or, they might change the air velocity with variable frequency drives, or install fans to circulate better and go back and measure again."

If any building system changes are made, the engineering team maps the environmental conditions for another three weeks, using qualification documents to track the process.

With the HOBO temperature and humidity loggers, the company's engineering and HVAC staff now has greater confidence in their temperature mapping capabilities. They are now able to keep closer tabs on the performance of their control systems, and have a proven method for protecting inventory and meeting federal requirements as well as their own high standards for quality assurance.