Which option is NOT a warning sign of a potential backdraft or smoke explosion?

• A. Smoke under pressure
• B. Excessive flames
• C. Muffled sounds
• D. Smoke stained or bulging windows

Answer: (B)

Excessive flames is not considered a warning sign of a potential backdraft or smoke explosion. Instead, it often indicates an open flame situation where combustion is actively happening. In contrast, warning signs of a backdraft or smoke explosion usually involve indicators of built-up gases and pressure.

Smoke under pressure signifies that gases are accumulating, creating a potential for an explosive situation if ignited. Muffled sounds or a lack of normal sounds in the environment can indicate that there is a lack of oxygen due to fires consuming available oxygen, which may lead to a backdraft. Smoke-stained or bulging windows suggest that the heat and pressure might be building up inside, manifesting in visual changes in the structure's windows. These are critical indicators that can help first responders identify a dangerous situation before it escalates.