All new temperature-controlled storage areas must be temperature-mapped as part of a fully documented verification process. Until this has been done, it is not safe to store temperature labile products in such areas. The temperature mapping procedures should;
Subsequent mapping exercises must also be carried out on a periodic basis in order to demonstrate continuing compliance. It is recommended to have 2 mapping exercises done at the hottest and the coldest seasons during an 18 month period. The recommendation is to perform the mapping for the facility as below;
In addition mapping should be carried out whenever significant modifications are made to the store. Examples include changes in the pattern of use that may increase loading or affect air circulation, or changes to the refrigeration equipment, such as an alteration to the set point.
Finally a remapping exercise may be justified whenever an analysis of temperature and/or humidity monitoring records show unexplained variability outside normal operating limits. All mapping exercises should be fully documented in order to demonstrate compliance to management, clients and the regulatory authorities.
A temperature mapping exercise is required for any space allocated for the storage and handling of products with a specified labelled storage temperature. This includes freezer rooms, cold rooms, temperature-controlled storage areas, quarantine areas and receiving and loading bays. It may also include laboratories. The permitted temperature ranges in these areas will vary – for example: -25°C to -10°C, 2°C to 8°C, 15°C to 25°C, etc.
Temperature mapping may also need to be carried out in spaces without active temperature control. A mapping study establishes the temperature distribution within the zone being mapped and it locates hot and cold spots. The collected data provides an essential source of information to ensure that all temperature labile products are correctly stored within their labelled temperature range(s). Mapping may also be used to identify zones where remedial action needs to be taken; for example by altering existing air distribution to eliminate hot and cold spots, or by retro-fitting new air distribution equipment to reduce temperature stratification in high-bay warehouses.
Our temperature mapping exercise involves a four stage process, as follows;
A mapping operation requires a sufficient number of Electronic Data Logging Monitors (EDLMs) to ensure that the temperature distribution in the space to be mapped is adequately characterized. In addition, suitable computer equipment and software is needed to store and analyze the data. The selected EDLMs must;
A detailed and comprehensive protocol will be prepared, reviewed and approved before the mapping exercise begins. A well-designed protocol will help ensure that the mapping study is correctly carried out. With suitable adjustments or options to cover the full range of temperature regimes, a standard protocol can be used to map any storage area in the facility. The mapping protocol should contain the following sections;
It may be helpful to use a generic floor plan or diagram to decide where each logger should be positioned.
Figure 1 shows part of a pallet racking cold room with an adjoining temperature-controlled packing area.
Figure 2 shows a small walk-in cold room.
STEP 6 – Record EDLM and thermostat locations: Record the EDLM locations on a temperature data logger location table for ease of traceability.
STEP 7 – Label and program the EDLMs:
Label each EDLM with a unique ID, taken from the temperature data logger location table. Enter the manufacturer’s serial number on the temperature data logger location table. Recording the serial number ensures that the device can be traced to its calibration certificate. Program each device, ensuring that the recording interval is the same – typically this should be set between 5 and 15 minutes. Set the same start time for all units. This is essential; otherwise the downloaded readings from the individual devices cannot be time-correlated. Make sure that the start time setting gives you enough time to fix all the units in position before recording begins.
STEP 8 – Fix EDLMs in position:
Fix the EDLMs in position. Make sure that each one is placed exactly as shown on the temperature data logger location table and drawing. Position and fasten the devices so that they cannot be damaged or displaced during the course of routine store operations.
STEP 9 – Conduct the mapping exercise:
Typically it should be run for a minimum of seven to 14 consecutive days for warehouses and other ambient storage areas. For temperature-controlled equipment which is not critically affected by diurnal or seasonal variations in ambient temperature (e.g. freezer rooms and cold rooms), the mapping study should be run for between 24 and 72 hours, or more if justified. If the room is fitted with duplicate refrigeration units – with or without automatic changeover – it is essential to map temperatures over a period that includes the operation of both units; preferably for a similar time period. The temperature distribution in the room may vary depending upon which system is running. At the end of the study, We collect the EDLMs and double-check their serial numbers and locations against the installation notes.
STEP 10 – Download the EDLM readings and consolidate the data for the study analysis.
The protocol should contain a template for the mapping report. This should include the sections listed below;
Introduction: A description of the objectives of the mapping study.
The report annexes should contain the following;
The final outcome and purpose of a mapping exercise is the implementation of the report recommendations. A detailed discussion of implementation is outside the scope of this document, but it could include any of the following outcomes;