Out of Tolerance Temperatures: How long before you Decommission a Storage Area?
We recently mapped a warehouse expecting it to be between 20˚C - 25 ˚C. Instead we found a number of temperature probes out of range. Is there an industry standard for the amount of time a probe can be out of specification before it is considered not able to store product or materials?
We have some probes that were out for up to five data readings (15-minute readings). We had a few that are out of range for hours. I know the areas that are hours out of range cannot store products that require 20˚C - 25 ˚C conditions. But what of the probes that are out of range for 30 – 45 minutes?
This study was during winter and we plan on performing summer studies as well. Any assistance you could give us is much appreciated as we want to close out the study for the winter season.
Thanks for reaching out!
In your mapping validation protocol, you should have specified exactly what data would meet your acceptance criteria. Something like: “Excursions under 60 minutes will be considered acceptable.” With acceptance criteria specified in your protocol, and with the protocol approved by your QA department, you are prepared for the scenario you describe.
Another approach is to have a generic mapping SOP that states acceptance levels, then reference the SOP in your protocol. Without these decision rules included in your study protocol, the proper approach is to document a deviation for all areas that showed temperature excursions during the mapping.
Let’s assume you have already done this and you and your QA department are now trying to determine what to do. From the perspectives of risk management and audit
preparation, the safest course of action is to change the control parameters for the warehouse (lower the set-point) and repeat the mapping. However, this is also a business decision, because operating the warehouse at a cooler temperature requires more energy and higher costs. Who wants to pay thousands of dollars in unnecessary cooling costs?
If you want to accept the mapping as it is, with known deviating areas, you need either an existing SOP that says this is acceptable or reference your product stability data that explicitly states that such periodic temperature excursions will have no negative impact on product quality.
However, this is risky and likely to draw questions from auditors. Questions increase your risk exposure, which in turn increases the likelihood that auditors will find another issue or problem. It is much safer to either repeat the study at a lower set-point to obtain data that matches the storage requirements or segregate those areas with periodic deviations.
One alternative possibility is to monitor the product temperature (inside the packaging) rather than the air temperature. This could cause your troublesome deviations to disappear. However, monitoring product temperatures will necessitate a procedural control for your warehouse to make sure that product has a minimum amount of packaging (not less than the packaging you used in your mapping) to be stored in the warehouse area (or, at least in the areas with deviations).
I hope this helps with your questions and please feel free to ask any further questions of myself, or my colleague Piritta Maunu as needed.