Which of the following is a method of extension detection during overhaul?

• A. Electronic Sensors
• B. Sight
• C. Sound
• D. Touch

Answer: (A)

During overhaul, finding hidden extension is essential to prevent rekindle, and relying on what you can see, hear, or feel behind surfaces can miss hidden hotspots. Electronic sensors provide an objective, non-contact way to detect heat signatures and embers behind walls, ceilings, and in voids. Tools like thermal imaging cameras identify elevated temperatures that aren’t visible to the eye, guiding you to where you need to probe and extinguish, even when the fire isn’t openly burning.

Sight, sound, and touch can still help, but they’re limited by visibility, muffled cues, and access, making them less reliable for uncovering concealed extension. Electronic sensors give a broader, safer, and quicker assessment to ensure all hotspots are found and fully extinguished.