What is the stage of fire where no smoke or flame is visible but gases are produced called?

The stage of fire where no smoke or flame is visible, yet gases are being produced, is known as the incipient stage. During this phase, a fire is beginning to develop, typically resulting from a heat source igniting combustible materials. The gases that are produced during this stage are often flammable and can contribute to the spread of fire if they find a sufficient ignition source. This stage is crucial for fire detection and prevention, as recognizing it can potentially allow for timely intervention before the fire grows to a more dangerous level.

In contrast, the flaming stage refers to the phase where visible flames are present, indicating that combustion is actively occurring. The fire growth stage encompasses the period when the fire spreads, and smoke becomes more noticeable. The rollover stage refers to the phenomenon where flammable gases accumulate at the ceiling and ignite, creating a fireball. Recognizing the characteristics of these different stages helps in effective fire management and safety planning.