When I am conducting training, I always ask if the firefighters use their thermal imagers (TIs) on every call that they go on, and I am amazed at the responses I receive.
Some will right off the bat say YES, they take the TI on every call with them; some respond to “only if it is required”; and the others have NO response, which tells me the TI sits in their apparatus and does not get used.
- Thermal Imaging Limitations
- Benefits of Using a Thermal Imager
- Fire Behavior and Thermal Imaging
- New Changes to NFPA Thermal Imaging Technology
- Thermal Imaging Archive
What does it take to get the message out there that a TI is an extremely valuable tool? Is it your lack of training and knowledge of how the TI works, understanding what image interpretation is, understanding on-screen symbology, or what emissivity is? Perhaps not knowing all the different applications a TI can be used for? How about thinking “outside of the box”? I always say that when you are called to something that requires you to get out of your apparatus with your full personal protective equipment (PPE) donned, your TI should be attached to you.
FACTORS AFFECTING TEMPERATURE MEASUREMENT
Do you rely on the spot temperature measurement (digital number) during your firefighting operations? National Fire Protection Association (NFPA) 1801, Standard on Thermal Imagers for the Fire Service (2021 ed.), removed this feature from Basic Mode operation in compliant TIs because of too many firefighters using the TI as a thermometer, which it is not designed to be. Temperatures can vary from ±5° to ±41° based on manufacturers’ specifications, but those temperatures could be plus or minus several hundred degrees in actuality. The spot temperature number is available for operation in Basic Plus Mode, but do not rely on it for 100% accuracy as it should be for a temperature range only. Factors impacting temperature measurement include the following:
Emissivity: Affected and changed by temperature of emitter, surface geometry, wavelength being measured, and surface roughness.
Angle of View: Affected by front, back, top, bottom, and both sides.
Atmospheric Attenuation: Affected and changed by particulate, gases, humidity/water particulate.
Focal Point/Area of Measurement: Affected by size of the area being examined or detected.
Optical Transmission: Affected by distance-to-spot ratio, or how far the TI can see.
Background/Reflected Energy: Affected by shiny or glossy surfaces—i.e., windows, shiny metals, etc.
LIMITATIONS
Infrared radiation has limitations, as it cannot pass through any type of material such as walls, industrial warehouse poly, or shower curtains, just to name a few. It also cannot pass through glass, which causes reflections as do other shiny/glossy surfaces—i.e., stainless steel appliances, gloss paints, wallpaper, ceramic tile, glossy hardwood, concrete, and linoleum flooring.
These reflective surfaces can cause multiple images such as false doors and windows and more firefighters than accounted for, so being aware of your surroundings is key for safety and accountability.
1 A reflective surface showing a second (false) door on the left side. (Photos courtesy of Bullard.)
2 A TI screen showing NFPA symbology icons.
HOW FAR CAN I SEE?
Every TI can see distances; how far those distances go depends on the type of TI you are using. TIs have a fixed focus with a focal range of 3 feet to infinity. This means any object located in that range will be in focus to a certain degree.
How far an object can be seen from a TI depends on the object being viewed and the surrounding background. Objects that have an elevated temperature variation, in relation to the surrounding background, can be seen at greater distances. A person would be visible from a greater distance at nighttime than during daytime. At nighttime, their heat/IR signature would be greater than the cool background. In daytime, the heated background would have a greater chance of masking or overriding their signature.
IN-HOUSE TI PRACTICAL TRAINING SCENARIOS
Here are some training scenarios to help with in-house training at the fire station using a TI.
Conduct interior observations inside the fire station using a TI.
- Electric panel (smells and bells): breakers (warm, warmer, warmest), fluorescent lights, ballasts, etc.
- All electric appliances: refrigerator, stove, microwave, computer equipment, printers, etc.
- Furniture: seat prints, heat signatures—how long will they last?
- Room layout: doors windows—means of egress.
- Washrooms: shower curtains, ceramic tile, mirrors—reflectivity.
- Stairs: judge distance (depth perception) using fundamental techniques to navigate up and down a flight of stairs.
- Wall prop: 2 × 4 studs with drywall and a heater mounted behind to simulate fire extension.
Conduct exterior size-up observations using the fire station and accessory buildings using a TI.
- Look at the building construction materials for different emissivity values—roof, walls, doors, windows. Conduct a complete 360.
- Morning before the sun comes up.
- Afternoon midday sun.
- Evening as the sun goes down.
- Check for other potential obstacles like power lines and fences.
Conduct observations for hazardous materials using a TI.
- Fuel containers, propane tanks—liquid levels, etc.
- Hot/cold liquids.
Two minutes to conduct a room search with a partner using a TI.
- Floor: black/white hole scenario. Require a metal sign or 2- × 2-foot × ¼-inch plywood that is a different temperature than the search room.
- Victim: hose dummy, rescue manikin heated up or use hot packs.
- Hot/cold: two 5-gallon pails of hot/cold water.
- Reflections: mirror or glass or white board.
- Smoke machine with cold smoke.
- Darkened room.
How much training do you need or should you have to be comfortable using a TI? These training scenarios are not going to make you 100% proficient using a TI, but they will help give you lens time, which is important as an end user to understand image interpretation.
MANFRED KIHN is a 19-year veteran of the fire service, having served as an ambulance officer, emergency services specialist, firefighter, captain, and fire chief. He has been a member of Bullard’s Emergency Responder team since 2005 and is the company’s fire training specialist for thermal imaging technology. He is certified through the Law Enforcement Thermographers’ Association (LETA) as a thermal imaging instructor and is a recipient of the Ontario Medal for Firefighters Bravery. If you have questions about thermal imaging, e-mail him at Manfred_kihn@bullard.com.
