Pharmaceutical temperature mapping is vital for every pharmaceutical company that distributes medicines. When storing and distributing medicines it is vital to ensure the effectiveness of temperature controlled storage systems, such as cool rooms, fridges and warehouses.
Temperature mapping locates the points of greatest temperature fluctuation and difference then analyses the causes of these. Temperature mappers measure during the ‘worst case’ conditions (summer and winter) to verify that the system maintains the correct temperature levels in all situations. The temperature mapping must accommodate a variety of variables that can influence performance.
- seasonal fluctuations
- sun shining predominantly on one wall of a building
And internal factors such as:
- airflow restrictions and
- the operation of the Heating, Ventilation, and Air Conditioning (HVAC) systems.
- doors opening & closing
Why is Temperature Mapping Important?
The temperature of different spaces within cooling rooms, industrial fridges and other controlled temperature environments can vary by up to 10°C. Typically, the central space within a chamber will maintain the most constant temperature, while the corners and areas surrounding the fans and access points will fluctuate. There is also external seasonal weather influence to take into account, especially in warehouses.
Temperature mapping is important for businesses and organisations dealing with temperature sensitive products, like biochemical products such as medications and vaccines, and all kinds of fresh and treated foods, especially fruit and vegetables, frozen foods, dairy and meat products. Verifying that the refrigeration systems maintain an acceptable temperature level for each specific product at all times is what temperature mapping is all about, and this is supported using ongoing monitoring systems.
Once the mapping has ascertained where the points of temperature variation lie within a temperature control system, then monitoring can be installed so that owners and users can prove their adherence to the related health and safety standards. It is also important that any backup systems be rigorously checked, according to the same principle of testing in extreme cases, to be sure that the chambers will work in less than ideal circumstances.
The Temperature Mapping Processes:
When undertaking pharmaceutical temperature mapping, it is important to know that different temperature measuring equipment will have different tolerances and response times to changes in temperature. Check that the equipment being used has sufficient accuracy ratings to give reliable data. For example, better equipment will provide readings that are accurate within plus or minus 0.3°C, whereas budget equipment may only have accuracy ratings of within 1.0°C. For products that must be stored within a limited temperature range, this budget equipment cannot provide sufficiently specific temperature assurance.
For warehouses, having information about the building’s external conditions is vital to effective pharmaceutical temperature mapping and monitoring, as warehouses typically have more directly external faces and walls than cool rooms and fridges, which mostly operate within an internal environment. It is common for warehouses to be mapped over a full year to make sure that all external conditions are accounted for in the data. This will also help determine where to place the permanent monitoring systems, as some parts of the chamber may be more influenced during specific seasons.
For temperature controlled rooms such as cold rooms and fridges, it can be sufficient to map the system once, based on the fact that the external environment is a controlled one. However, it is advisable to make sure that the HVAC systems of these buildings or environments are not heavily influenced by other external forces that could change their temperatures significantly. The mapping of a cool room in a warehouse should take into account the fluctuation in the warehouse temperatures and conduct the tests during its most extreme levels.
Load testing is another important part of the temperature mapping process. Load testing investigates how expected product levels interact with individual temperature controlled chambers. Things to take into account are whether the product will arrive in the required condition or if cooling is necessary, as this can dramatically alter the temperature in the chamber. Testing should verify whether the chamber can cope with the maximum specified load arriving all at once to then be cooled. If it can operate properly in this situation, as well as operating effectively at full capacity, the chamber can be considered sufficiently load tested.
It is also advisable to test the system’s performance by simulating failures, to ascertain whether the system could be used even while experiencing some equipment failures.
Once the mapping process has been completed, sensors should be installed to allow for continued surveillance of the areas that have been identified as being most influenced by temperature change. The stable areas should also be monitored to help with trouble-shooting if any parts of the system stop operating properly. Having on-hand data about what’s really going on inside temperature controlled spaces is vital to businesses for protecting their product investments.
Monitoring systems should be planned and documented according to the scientific rationales shown by the temperature mapping procedure. This development strategy should then be reviewed and qualified (IQ, OQ and PQ) to pharmaceutical standards. Sensors should be placed around the products, around major potential temperature influences such as doors and cooling fans, and at different heights, especially in larger chambers.
Different countries have different temperature control standards, so when planning the layout of the monitoring system it is helpful to refer to the relevant guidelines. These will recommend the minimum number of sensors to install according to the volume of the chamber being measured.
Sensor equipment can be effectively split into zones according to areas in the temperature controlled space which are affected by similar influences. For example, in a square or rectangular chamber, the zones in corners away from doors will behave much the same as each other, as will the zones adjacent to doors or fans. If the monitoring devices are zoned, the operational data can be compared to provide averages and overall information on how the system typically functions.
One recommendation is to install each sensor in a thermal lag (individual containers of thermal fluid like glycol). This mimics the protection given to products by their packaging, and slows the sensor’s response to brief temperature interruptions, like personnel movement and product removal or loading. This makes the sensor more accurate in terms of how small temperature shifts actually affect the products. Again though, it is important to test to make sure that the mitigating effects of the thermal fluid match the effects of the products’ packaging materials.
Pharmaceutical temperature mapping provides information on warmer and colder areas within temperature controlled environments, and supplies details on the overall operation of the system. After temperature mapping a system, monitoring equipment can be installed to provide real-time feedback on system operations and its stability for product protection.
Want to know more? Read our article on WHO on Temperature Mapping of Storage Areas.
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