New Changes to NFPA Thermal Imaging Technology

Over the years, there have been many improvements in thermal imaging technology. From reduction in size, enhancement of imagery, down to the pricing, all these changes and improvements affect the fire service, both big and small.

But what happens when changes are made beyond the thermal imaging manufacturer? How do standard changes impact the fire service?

Aside from manufacturers changing their technology over the years, the National Fire Protection Association (NFPA) also plays a significant role in the driving force for many changes in safety improvement. The new NFPA 1801, Standard on Thermal Imagers for the Fire Service—2021, has revealed new editorial changes from the previous (2018) standard. These changes may be confusing and leave some wondering how this will affect thermal imaging use for the future. I would like to break down these new changes, focusing on the chapters that pertain directly to the fire service, to help others understand what they mean and how this will affect them.

The new standard changes are organized by chapter, making it easier to dissect. Chapters 3 and 6 pertain directly to the fire service, while chapters 4 and 8 primarily affect the thermal imaging manufacturers. It is important to note that these changes just came into effect on June 4 and only apply to NFPA 1801-certified thermal imagers (TIs).

Digital temperature measurement

Chapter 3 Overview

3.3.29 Thermal Imager (TI). Special electronic equipment that creates a picture based on the heat produced by a person or object. Integrated TI. A removable or nonremovable TI that is an integrated part of another item or items of protective clothing, protective equipment, or both. Nonremovable. An integrated TI that is not removable and cannot be used independently of the item or items with which it is integrated. Removable. An integrated TI that is removable so that it can be used independently of the item or items with which it is integrated. Stand-Alone TI. A TI that is not an integral part of any other item of protective clothing or protective equipment.

Chapter 3 Breakdown: Ever since TIs entered the fire service, the acronym for thermal imaging cameras—TIC—was most commonly used. Many devices looked and operated like cameras; however, some did not and were still referred to as a TIC. Because of this, NFPA 1801 has standardized their terminology as thermal imager (TI).

Chapter 6 Overview

6.4 TI Basic Operational Format.

6.4.3 TI BASIC operational format functions shall include the following:

(1) Grayscale imagery with white-hot polarity.

(2) Power source status indicator.

(3) Internal electronics overheat indicator.

(4) Thermal Imager “on” indicator.

6.4.4 In addition to the requirements specified in 6.4.3, the TI BASIC operational format shall be permitted to also include only the following:

(1) Heat indicating color and, if so equipped with heat indicating color, a heat color reference bar.

(2) Audio, video, and data recording.

(3) Audio, video, and data transmission.

6.5 TI BASIC PLUS Operational Format.

6.5.2 TI BASIC PLUS operational format shall be permitted to have additional functions, enhancements, and innovations beyond TI BASIC, provided by the manufacturer, that require additional or specialized instruction or training in addition to the TI BASIC operational format training.

Chapter 6 Breakdown: The digital temperature measurement—not to be confused with the sliding bar scale temperature measurement feature—has been removed from the TI BASIC operational format to the TI BASIC PLUS operational format.

Despite TI manufacturer user manual warnings advising not to use temperature measurement to make tactical decisions, it became apparent in three recent NIOSH Firefighter Fatality Investigation Reports that there is a lack of understanding, on behalf of the fire service, of the feature’s capabilities. Although the use of the temperature measurement feature was not considered the sole factor in the fatality investigations, its use (and potential misuse) certainly could be a factor in a series of events that attributed to these firefighter injuries and fatalities.

The move from the TI BASIC to TI BASIC PLUS operational format is further substantiated in all previous editions of NFPA 1801 in Subsection 6.5.2, which requires additional training for TI BASIC PLUS operational format functions, enhancements, and innovations beyond TI BASIC.

As someone who uses thermal imaging on a regular basis, I can certainly understand why the NFPA removed the digital temperature measurement from the TI Basic mode. It can surely be a distraction, as you should be focusing on the images being displayed and understanding their interpretations, not on what the temperature is telling you, which could be inaccurate.

Remember that TIs use what is called a Relative Heat Indicator (RHI), which measures a relative temperature of a solid surface or liquid—not gases, flames, or a room’s temperature. There are too many factors that can affect this temperature measurement, including the following:

Emissivity—which can be affected and changed by the temperature of the emitter, surface geometry, wavelength being measured, surface roughness, and angle of view.

Atmospheric Attenuation—dust particulate, gases, humidity, water particulate.

Focal Point/Area of Measurement—distance to spot ratio.

Background/Reflected Energy—shiny glossy surfaces.

This numeric temperature indicator was previously located in the lower right corner of the TI’s display screen, under the Sliding Bar Scale Heat Indicator and Heat Color Reference Bar. This was found to be very distracting, as it was constantly moving up and down.

Since thermal imaging technology continues to improve and the NFPA standards reflect these changes, we must continue to be diligent in our training to understand these innovations and to stay safe in doing our job as firefighters. The more you understand your equipment, the better you can use it on scene.


This article by Manfred Kihn was published in Fire Apparatus Magazine in August issue 2021.