UNITED STATES—Environmental monitoring is only as successful as the checklist being followed for data sampling. But before we take a closer look at what a good checklist should have on it, let’s explore environmental monitoring a little deeper.
In many different applications, the conditions within a selected zone may require monitoring. This environment may be an enclosed area such as an industrial factory, a food processing plant or a medical storage facility. The environmental conditions within these spaces would need to remain constant to prevent spoilage and to ensure compliance for various regulatory bodies. The most cost-effective, reliable, and accurate way to accomplish this is with a data logger.
A data logger is an electronic device that monitors and records specific environmental conditions. For the examples listed above (industrial factory, food processing plant, or medical storage facility) the conditions that would be monitored would most likely be temperature and humidity. Other data loggers can monitor various additional conditions depending on the specific application. Essentially, data loggers “watch” conditions on an ongoing basis.
The following items listed below are the basic points that should be included on any environmental monitoring checklist. Specific applications may warrant the need for additional items to be included. The list below is intended to provide you with a general template.
This is where you will outline how often the data logger should record a sample of the temperature and/or humidity. This is the definition of your “sampling rate” and it can be as often as you see fit for the conditions you are monitoring and the site location being monitored. On average, a data logger can be set to record temperatures every six, fifteen, or thirty minutes. Again, depending on the specific site and purpose of the monitoring, that interval can be increased. Once the interval is set with the data logger, it will continue to sample at that rate until you change it.
According to Dickson, before setting the data logger for a sampling session, you should ensure that it is fully powered. This means loading new, fresh batteries or completing a full charge for units that use rechargeable batteries. Failure to do this may result in faulty readings.
The settings you program into the data logger should be the high and low range permitted to maintain compliance. Should a temperature or humidity level fall outside of either end of the settings range, an alarm alert should be armed. Ideally, the alarm should be programmed to go off at temperatures that are at the high and low limits to provide a warning system.
Example Temperature Settings:
Refrigerators – High Temperature 46F, Low Temperature 36F
Freezers – High Temperature 5F, Low Temperature -58F
The alarms should be set to go off if the refrigerator and/or freezer reaches the high/low temperature or has been out of range for at least 30-minutes.
- Data Recording Limit
The interesting thing about data loggers is that they will continue to record information long after they have run out of memory. Using a loop memory system, once a data logger memory is full it will begin to record information by overwriting the oldest data files in the memory. You can prevent this from happening by setting the data logger to stop recording once the memory is full.
- Temperature Monitoring
As an added backup, it is not uncommon to include manual temperature monitoring in addition to a data logger. This can be done by having someone assigned to check the storage unit and confirm a manual temperature reading in a logbook kept on site.
- Data Collection Details
When it comes to what to do with all that data, here are a couple of simple guidelines to help you stay on top of it.
You should download the information collected on your data logger no less than twice a month.
Best practices point to reviewing the data that has been downloaded to a computer at least once a week.
The data logger memory should be deleted/cleared completely once it has been downloaded and saved to a computer.
The temperature measurements recorded should be consistent and match (within a fraction of a degree) between the data logger and the manual temperature log.
- Reporting Guidelines
Here are a few suggestions to add to your environmental monitoring template regarding the reporting of the data collected.
Depending on the purpose of your temperature monitoring, you may be required to retain all data logger information (which should be stored safely on a computer) and the paper temperature logs for a period of up to one year or more. This means you will have to develop a storage system for both the electronic and paper data.
Again, depending on the specifics related to your environmental monitoring requirements, all data (electronic and paper) must be accessible should it be required to be submitted to health authorities or any other regulatory body for examination.
If at any time there appears to be an issue with the data logger that requires the unit to be packaged and shipped to the manufacturer for repair or replacement, you will need copies of the temperature readings (digital and manual). The readings that were recorded before any issue developed should be accessible and available to provide to the manufacturer so that it can assist with troubleshooting the problem.
As stated above, a data logger will only do the job that the checklist outlines. Once you reach the end of the checklist, your job is done and the work of the data logger will stand. Keep in mind the purpose of the environmental monitoring equipment and do not try to push it past its limits. The average data logger should provide you with years of dedicated service, provided you operate it within the parameters it was designed to monitor and track. By following the guidelines noted above, your data sampling will be solid and accurate when needed.