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Monitoring Revisited

While most pharmaceutical quality managers realize the importance of temperature and humidity tracking to guarantee both quality and compliance, the way in which many go about it is adding hidden costs. Technology for temperature/humidity tracking continues to evolve, and there are numerous time-saving features in recent temperature/humidity data loggers that can make a difference. On one hand, some quality managers are doing too much to track temperature /humidity data, while on the other hand some are doing too little. For many, it’s timely to revisit temperature and humidity monitoring. Here are some key points to consider.

Keep Calibrations Current
Temperature and humidity data loggers and chart recorders need to be recalibrated periodically to ensure the accuracy mandated by FDA 21 CFR Part 11 and GMP guidelines. If there is a problem in this regard, it generally stems from quality managers doing too little. One problem is letting the instruments go without recalibration beyond the period recommended by the manufacturer and/or the tolerances of applications. Another problem is that some do not understand the various options associated with different types of re-calibrations, and opt for the least expensive ones that are usually inadequate for 21 CFR Part 11 compliance. At issue is the inclusion or exclusion of determining what is called “before” data. Before data is comprised of readings documenting a logger or recorder’s readings before it is recalibrated. If one skips this step, then there is no way of documenting how close/far off the instrument was to acceptable ranges before it was recalibrated. This lack of data compromises decisions on product quality and will leave you vulnerable to charges of negligence in a court of law, if product quality issues do arise.

No matter how hectic production schedules may be, there is now little reason to lose track of calibration schedules because of the existence of free services that send notifications on scheduled calibrations for all instruments. Click herefor more information on Dickson's Calibration Club.

Keep Mapping Current
Most quality managers in pharmaceutical plants know very well that temperature and humidity conditions in production facilities and warehouses need to be systematically mapped. Such mapping exercises enable the remediation of trouble spots that are creating uneven conditions such as drafts or blocked air flow. Systematic mapping needs to be done in several stages in order to determine if remediation steps taken, such as adding fans or plastic curtains, have been effective.

However, that initial warehouse mapping exercise is typically not the last, nor should it be. For starts, different seasonal conditions necessitate repeats of warehouse mapping exercises because the challenges to uniform conditions will predictably vary from one season to the next. What is more commonly overlooked is that ongoing changes to facilities require mapping anew as well. For example, shelves that were previously lightly packed that evolve into tightly packed inventory in ceiling-high packaging might in itself change the airflow from the initial conditions. Or, a new production process that requires more or less heat may be affecting conditions in the facility. Plant expansion is obviously a time to revisit the facility mapping, but is also sometimes overlooked.

On the other hand, taking humidity/temperature readings too often can also create significant burdens by adding data processing time. Typically, 15-minute intervals provide enough data to evaluate humidity/temperature trends because it takes a relatively long time for conditions to change in a room, and certainly in a large open production facility or warehouse. If one samples in one-minute intervals, one is generating 15 times the data to process; if one samples in 2.5-minute intervals, one is generating 6 times the data to process, if one is sampling every 10 minutes there is 1.5 times the data to process, and so forth. More frequent sampling is not making any meaningful contribution to data analysis but rather IS adding time to data processing. This is turn ties up computer resources and uses up staff time unnecessarily. For a more detailed discussion on how to appropriately scale data collection for temperature/humidity mapping, click here.Perhaps one reason why some quality managers try to take short cuts with temperature/humidity mapping is that their approach to this task makes it needlessly onerous. One mistaken approach is the attempt to cut corners by buying fewer data loggers than are actually needed. Studies have shown that spacing temperature/humidity loggers every 3,000 – 5,000 feet in an open warehouse lacking walls to block airflow is adequate to create meaningful data. When there are predictable trouble spots such as doors or air conditioning vents more may be needed. Mapping can take on the appearance and efficiency of the Keystone Cops if one is wasting time moving loggers from spot to spot. Mapping points are the same no matter how many loggers you use; the difference is in the labor costs in doing the mapping. Since recorders and data loggers used for temperature/humidity mapping typically have continued economic life as ongoing quality control tools, and since on the scale of things these are not very expensive instruments, keeping labor costs in check by ensuring an adequate supply of loggers for time-efficient mapping is advisable.

Streamlining Data Downloads
Those who are using earlier models of humidity/temperature data loggers are restricting themselves to instruments that involve more labor time than needed. The earliest data loggers were more or less of one type, essentially a computer without a monitor. These data loggers then required you to download data to a PC.

There is now a wide range of displays in different types of humidity/temperature data loggers. Some allow one to see what the current conditions are without going through the bother of downloading data. Others will add to that a display of the minimum and maximum temperatures and/or humidity in pre-defined timeframe's that allow determination of out-of-range conditions at a glance. The premier type displays are somewhat larger, typically 4 – 5 inches wide, and are capable of providing graphical displays comparable to those formerly created on PCs after download and processing. The graph-at-a-glance type humidity/temperature data loggers obviously have potential to save an enormous amount of time and have the added advantage of making ample data available to a wide range of personnel.This information is critical for process and quality control purposes and needs to be accessible to personnel as they walk around the plant.

If one prefers the downloading data route there are innovations here as well that can significantly impact the time required for temperature/humidity


Too often, readings can also create significant burdens by adding data processing time. Typically, 15-minute intervals provide enough data to evaluate trends because it can take time for conditions to change in an environment

monitoring. Thank the proliferation of digital cameras for spawning affordable flash memory cards that are now used in data loggers. These allow one to leave the logger in place and instead take the flash memory card to the PC for processing, just as one takes a flash card from a digital camera to process at a PC. These not only save the bother of moving loggers around but also enable an immediate reloading of a replacement flash card when one is removed, such that there is a negligible gap in data collection. These flash cards are very inexpensive, easy-to-obtain, commodity type items that are available in varying capacities. Flash card selection should be based on how often the downloading of data is desired or required by an application.

Recent models of humidity/temperature data loggers allow for Ethernet connectivity. That means that one user can plug the logger into their Ethernet connection for data downloading and workers in a more remote areas can see the data as well.

Better Options for Varied Applications
Beyond saving time, the recent trends in humidity/temperature loggers are to build in features that boost performance in varied conditions. For example, many temperature data loggers come in stainless steel enclosures now. For some, this is simply an aesthetic improvement, but for others it enables use in harsher conditions and also under water because stainless steel won’t corrode or deteriorate.

The same trend we see of greater processing power in smaller sizes in all portable electronic equipment is true of humidity/temperature data loggers as well. There are now very compact loggers the size of a quarter that are relatively inexpensive and ideal for tracking container conditions during shipping. 
Simple as it may sound, push-to-start buttons are a feature added to data loggers that simplify pharmaceutical shelf life tests, tracking shipping conditions, and the like.

Reputable manufacturers of 21 CFR Part 11 compliant temperature/humidity data loggers and chart recorders now offerpharmaceutical firms a wider array of options on how to approach monitoring environmental conditions that affect product quality. Finding sources that have many different models of loggers and chart recorders will help ensure that the ones most suitable to specific applications are selected. Time savings and better performance in various production and shipping scenarios are key benefits of trading up to newer temperature/humidity data logger and chart recorder models. Taking the time to revisit the range of humidity/temperature data loggers and chart recorders is advisable.


About the Author: Chris Sorensen is VP of Dickson Company (, which offers the widest range of data loggers and chart recorders available in the world for pharmaceutical and other applications. Inquiries can be directed to
FAX 630.543.0498
930 S Westwood, Addison IL, 60101

Copyright Carpe Diem Communications, Inc. Reprinted with permission from PFQ magazine.