Most people imagine flames. In reality, smoke kills far more people than burns do — the majority of fire deaths are caused by inhaling toxic smoke and gases, often before the victim is aware of the fire.
| HAZARD | EFFECT |
|---|---|
| Carbon monoxide | Odourless; causes confusion then unconsciousness |
| Hydrogen cyanide | Released by burning foam and plastics; rapidly toxic |
| Hot smoke | Damages the airway; blinds and disorientates |
| Oxygen depletion | Impairs judgement long before it causes collapse |
A room can go from a small flame to full involvement in under three minutes. This is why the emphasis is on early detection and immediate evacuation rather than on firefighting.
| METHOD | HOW |
|---|---|
| Conduction | Heat travels through materials — metal beams, pipes |
| Convection | Hot gases rise, spreading fire upward and along ceilings |
| Radiation | Heat crosses a gap and ignites materials without contact |
| Direct burning | Flame passes along combustible material |
Convection is the main route in buildings — which is why stairwells and ceiling voids must be protected, and why fire doors matter so much.
A closed fire door holds back fire and smoke for a rated period, typically 30 or 60 minutes, creating a protected escape route.
A wedged-open fire door defeats the entire system. It is one of the most common and most serious findings in fire inspections, and it is the single easiest thing for any employee to put right.
Prevent — do not create hazards, and report those you see.
Warn — raise the alarm immediately on discovering a fire.
Evacuate — leave promptly by the nearest safe route and go to the assembly point.
Everything else in this course elaborates on those three.