This article answers the most frequently asked questions surrounding Infrared Thermometers and their role within the food production industry.

The accurate measurement of product temperature is essential to food safety, product quality, and audit compliance. As one of the most popular instruments for this task, Infrared Thermometers are an important piece of equipment within the food industry.

However, as with any technical instrument, there are naturally going to be questions surrounding use, function, and best practice.

In an effort to provide clarity in these areas, we have answered the most common questions surrounding Infrared Thermometers, covering everything from emissivity settings to equipment calibration. If you have any additional queries, you are welcome to contact us on 01473 461800 or sales@klipspringer.com. 

How do Infrared Thermometers work?

Infrared Thermometers are non-contact temperature sensors that measure the heat (infrared) energy emitted from an object.

Able to detect and capture thermal radiation, they generate a temperature reading without the need for physical contact or product penetration.

Used throughout the food production industry, Infrared Thermometers are typically relied upon during goods-in / goods-out applications. They are a popular choice for the monitoring of frozen food products.

Infrared vs Probe Thermometers

As mentioned above, Infrared Thermometers are often used as the first point of temperature validation during goods in / goods out processes. However, if the results of your Infrared Thermometer suggest a product temperature sits outside the expected limits, you will need to follow-up this initial check with a Probe Thermometer – placing the probe either inside the product or between the packaging.

This additional step is necessary because Infrared Thermometers measure the temperature of an object’s surface, but cannot tell you the internal temperature.

With this in mind, sites will often opt for a Dual Thermometer such as the IRTLC 750i – featuring an infrared sensor and a folding penetration probe. This hybrid instrument simplifies the process of measuring a product, then validating the measurement, as both functions can be completed using just the one unit.

Learn more about Dual Thermometer probes

What is the min/max distance you can hold the thermometer away from a product?

Every Infrared Thermometer has something called a ‘distance-to-spot’ ratio. This tells you the diameter of the area being measured in relation to the distance of the thermometer to the target.

Say your thermometer has a distance-to-spot ratio of 12:1, it will be able to measure (approx) a 1 inch diameter spot when it’s 12 inches from the target. However, if you try to use this thermometer to measure a 2 inch area from even just a metre away, you’re not going to secure an accurate result because the instrument will also be measuring the temperature outside the intended area.

To avoid this issue and secure accurate results, you will have to pay close attention to the distance-to-spot (D:S) ratio included in your instruction manual. This ratio will also be displayed on the right hand side of the unit.

It is also worth noting that some Infrared Thermometers, such as the LAZASCAN 205, feature twin beam laser guides that allow the operator to directly control the area of the sample size.

Find out more about the LAZASCAN 205

What factors impact Infrared Thermometers and how they work?

There are six key factors with the potential to impact the results of your Infrared Thermometer.

1. Angle of measurement: Infrared Thermometers are supposed to be held at a 45° angle and aimed correctly. If this isn’t the case, the displayed value will be inaccurate. The user should also make sure the target area is clean and any potential obstacles have been removed.

2. Environmental temperature: if an Infrared Thermometer is quickly moved between two environments with very different temperatures, the accuracy of the instrument will be temporarily compromised. Ideally, the Infrared Thermometer should be introduced to a new environment at least 30 minutes before it is used to take a measurement. This will leave enough time for the temperature of the thermometer to align with the temperature of the environment.

3. Air quality: pollutants in the air such as smoke and dust will make it difficult for your thermometer to receive enough infrared energy to produce an accurate reading. This could also be an issue if the lens of your Infrared Thermometer is unclean.

4. Reflective surfaces: the accuracy of Infrared Thermometers can be impacted by reflective surfaces. You should be especially wary when measuring the temperature of shiny metal objects, but even reflective, glossy packaging can affect accuracy. One solution is to put a piece of non-reflective tape over any shiny items you wish to measure.

5. Emissivity settings: the ’emissivity settings’ of an Infrared Thermometer determine how effectively it can measure the infrared radiation emitted by different materials. Depending on the model of thermometer you select, it might be possible to adjust the emissivity settings to match the properties of the surface being measured – enhancing the accuracy of your results. One example of this is the IRTFI550 Infrared Thermometer.

6. Temperature range: along with emissivity settings and distance-to-spot ratios, Infrared Thermometers also have a temperature range within which they provide the highest level of accuracy. If the temperature of the product you are testing sits outside this range, this could impact the precision and reliability of the results you receive.

Learn more about the IRTFI550 Infrared Thermometer

How do you check the accuracy of an Infrared Thermometer?

For the sake of food safety, product quality, and audit compliance, it is essential that you verify the accuracy of your Infrared Thermometers on a regular basis. There are two popular methods:

Comparator Pot

1. Place the Comparator Pot in the room where the verification will be taking place, giving it at least one hour to stabilise to room temperature.

2. Take a Reference Thermometer with a penetration probe and insert it into the base of the pot. Leave your Reference Thermometer to stabilise.

3. Hold your Infrared Thermometer perpendicular to the Comparator Pot, pointing it directly at the black bottom inside. If your Infrared Thermometer has laser guides, you can use them to ensure you are aiming correctly.

4. We recommend taking three separate readings using your Infrared Thermometer, then compare the readings to the one generated by your reference probe.

5. Record the readings in your calibration log. Any difference between the two instruments is an indication of the accuracy drift.

Dry-block Calibrator

Alternatively, if you are looking for a quick and easy way to verify multiple Infrared Thermometers in one go and at more than one temperature point, another option to explore is a Dry-block Calibrator such as the LazaPort8.

In addition to eight ports along the front for the checking of Probe Thermometers, the LazaPort8 has two temperature blocks at the top for the checking of Infrared Thermometers.

1. One block will be at a low temperature such as 0 – -18°C and one block will be at a higher temperature such as 100°C.

2. Point your Infrared Thermometer at the top of the first block and gain a stabilised reading. We recommend taking three separate readings to ensure you get a consistent result from your Infrared Thermometer.

3. Repeat this process on the other temperature block, aiming your Infrared Thermometer at the centre of the circle.

4. Record the results in your calibration log.

Find out more about Temperature Comparator Pots
Learn more about the benefits of the LazaPort8

What is the process for calibrating an Infrared Thermometer?

Along with the regular verification of your Infrared Thermometers, you will also need to schedule in external calibrations. This is another crucial step in maintaining the accuracy of your equipment.

At Klipspringer, we are able to take care of this for you thanks to our in-house, UKAS-accredited laboratory. We are also able to manage the calibration of your LazaPort Dry-block unit. Your calibration certificates can then be stored on our Online Equipment and Certificate Portal, with reminders sent to you whenever a due date is getting close.

Learn more about Calibrations and Servicing from Klipspringer

You now have the answers to the most common questions surrounding Infrared Thermometers and the role they play within the food production industry.

Explore our wide selection of Infrared Thermometers
Discover our full range of Thermometers and Probes

If you require any further guidance, Klipspringer would be happy to help with your enquiries. Our in-house Technical Team will be available to provide support and relevant resources. You can also contact us on 01473 461800 or sales@klipspringer.com. Alternatively, you can use the form below to arrange a consultation. 

If you would like further guidance relating to Infrared Thermometers, the Klipspringer team would be happy to help. Share your details below to arrange a free consultation.