A temperature logger is composed of a temperatura sensor, an electronical memory, a micro controler and a battery.
It can have an external temperature sensor or an internal temperature sensor. It is the case for the Thermo Button, the temperature logger that includes all these elements in its stainless steal can.
A temperature logger enables to mesure temperature with a regular sample rate and to save the temperature data in its memory. It gives you a complete log that enables the control of temperatures for a specific period of time.
A temperature logger is usually used for cold chain control in the pharmaceutical or in the food industries. Indeed, cold chain regulations require these sectors to track temperature during the transport and the storage of the products.
Cold chain includes all the operations for products preserving (most of the time food or pharmaceutical products) with a low temperature in order to protect their qualities. The standards will be different according to the product (+2 to +8°C for vaccines or many pharmaceutical and food products, and even lower temperatures for products like fish).
The word "chain" put into relief the importance of continuity. All the members of the chain have to control temperature.
Cold chain respect requires the use of control devices like temperature loggers.
HACCP (Hazard Analysis Critical Control Point)
According to the definition of the standard NF V 01-002, the HACCP is a system that "identifies, assesses and controls the critical hazards for food security"
The HACCP is not a standard, but a tool that identifies, assesses and controls the critical hazards for food security. The HACCP is composed of 12 steps, like hazards analysis and the identiication of critical points, in order to control them.
The 3 categories of critical points are the following:
In most of the cases, temperature tracking is one of the most important critical points and the quality manager will have to control the cold chain. They use thermometers or temperature loggers like the Thermo Buttons for cold chain control.
The standard EN 12830 describes the metrological, electrical and mechanical qualities that a temperatura logger must have for the «transport, storage and the distribution of frozen or deep frozen food products and ice-creams"
The standard EN 12830 indicates that the loggers must have an accuracy of ±1°C between -30°C and +30°C and a response time of 5 minutes.
The standard was originally written for the food industry, but it has been applied then in all sectors and also for the pharmaceutical sector.
The temperature loggers Thermo Buttons have been tested and are EN 12830 compliants. The corresponding certificates are available here (Fr) or here (En)
Standard NF X 15-140
The standard NF X-15-140 concerns the characterization and qualification of climate and thermostatic chambers, called "chamber mapping" as well.
This standard enables to check if a chamber (refrigerator, steam cabinet, warehouse...) has a stable and homogeneous temperature. The general goal is to check that the setting value is respected and does not exceed the maximun and minimum limits. For example, a bactoriological steam cabinet has to have a temperature of 37°C (Setting value) and remain between +36°C and +38°C (max. variation 1°C).
The mapping of a chamber of less than 2 M3 has to be made with a minimum fo 9 temperature loggers scattered in the corners and in the center. For the chambers from 2 to 15m3, the characterization must be made with 15 temperature loggers. For chambers bigger than 15m3, the standard does not require a specific number of temperature loggers.
Futura Science describes calibration as the "Action of setting a device comparing to standard data in order to get the most relevant log". It can be applied to devices in relation with sound(amplifier...) or image (monitor, video projector, television)"
In the case of a temperature logger, the calibration enables to correct the desviation comparing to a standard.
Calibration (comparison with standard)
Calibration means all operations that enable to compare a temperature instrument with a standard, in order to check the accuracy of the instrument.
The calibration of a temperature logger is made by comparing it with an accurate thermometer or another logger. Of course, the standard must be more accurate than the instrument to calibrate.
In a metrology lab, the calibration is made in a bath that guarantees a homogeneous and stable temperature. If you don't have any bath, you can place the temperature logger in a bowl with sand or with crushed ice. The use of crushed ice for the calibration of a thermometer or a temperature datalogger is a solution to have a temperature of 0°C if you don't have any bath.
A calibration must be made with the calculation of the uncertainty that validates the method and the result.