The process of temperature calibration is a relatively detailed and technical scientific process. Although calibration work can be done outside of the laboratory environment, we don’t generally recommend it. We have attempted to explain some of the science involved in the calibration process below.

What really is the true temperature?

One of the key components in running a calibration is to provide an accurate reference temperature to test against. Typically this is achieved with a liquid bath such as these found here:

These baths are very expensive, but they provide a steady temperature usually within 0.1°C and also provide the ability to adjust the temperature so a multi-point calibration can be performed.

“True” temperature is generally defined by traceability to a NIST standard. Read more about traceability here. In other words, if an expensive, high grade temperature bath reads a temperature of 100°C, how do we know it is really 100°C? Perhaps we have a thermometer which was tested against another thermometer, which was tested using a high precision thermometer which was calibrated at NIST’s testing laboratory directly. In this case, we would have a “chain of traceability” back to the NIST standard and thus we would have a true reference temperature standard. Testing at NIST directly is feasible for anyone however the calibration fees run approximately $3,000 to $18,000. See page 33 here.

What is a practical way to run a calibration without expensive equipment?

In lieu of an expensive temperature controlled liquid bath, an ice water bath can be used to provide a zero point (0°C) temperature reference. Although this is generally inexpensive, it is still potentially difficult to establish a true zero point reference. Difficulties include:

Follow these steps to perform an ice bath calibration on the FireBoard here.

Is the FireBoard already calibrated?

Each FireBoard is calibrated at our lab before it ships. We use high precision resistors which simulate temperature which results in a precise temperature curve for each thermometer. This calibration is not NIST traceable, but we do have the ability to send the FireBoard to a separate testing facility for an extra charge. This additional calibration would include a NIST traceable certificate.

How can the FireBoard be adjusted if an error is found?

A user can input a temperature offset per channel if necessary, but we urge caution in making these adjustments since each FireBoard is already calibrated. We encourage customers with any concerns about temperature discrepancies to perform a check using an ice bath using the above instructions. To input offsets in the FireBoard follow these steps below:

When the FireBoard is powered on and connected to the mobile app via Bluetooth, navigate to Devices > Advanced Settings > Probe Configuration. Each channel can be configured for an offset, which is with respect to the degree type currently selected (Celsius or Fahrenheit). For example, if a channel is found to be 0.3°C too high, a -0.3°C should be entered to offset this error.