List three common signs of hidden fire that overhaul crews monitor.

• A. Warms/heat in walls or ceilings, smoke emitting from cracks or voids, and a strong odor of smoke near concealed spaces.
• B. Visible flames in attic, cracking glass, sudden cool spots.
• C. Water pooling, rustling sounds, loud pops.
• D. No heat, no smoke, no smell.

Answer: (A)

Hidden fire in overhaul situations often hides behind the building’s structure, so crews focus on signs that indicate smoldering embers inside walls or ceilings. The three common indicators are warmth or heat building up in walls or ceilings, smoke seeping from cracks or voids, and a strong odor of smoke near concealed spaces. Heat shows that there are still energized materials storing energy, and smoke and its smell are products of combustion traveling through hidden cavities, signaling active or recently active smoldering fires that could reignite if not found and cooled.

Active flames in an attic would be an obvious, visible fire, not a hidden one. Sudden cool spots, water pooling, or other sensations don’t reliably pinpoint hidden fire activity in concealed spaces, and a lack of heat, smoke, or odor would suggest no fire is present, which isn’t the scenario overhaul crews are preparing for when searching for hidden embers.