It is easily deducible that the effects of a fire are catastrophic on people, animals and things. Besides the harmful, sometimes lethal, consequences of the byproducts of combustion, consequences that we showed in other pages, there is the progressive decrease of oxygen in the air, leading to a further decrease of the ability to breathe for who is in the area where the fire takes place, combined with other side effects, like the restriction of muscle movement, headache, vertigo, weakness, nausea, vomiting and paralysis. Moreover, smoke limits visibility: combined with the eventual structural failure of the building where the fire has developed, it can be the cause of bone fractures and more or less serious wounds.
FIRE RESISTANCE OF DIFFERENT MATERIALS
Toxic gases, excessive heat and smoke damage not only living beings, but also goods and buildings. Knowing how different building materials react against fire is very important in order to be able to evaluate the risk of collapsing of a building when extinguishing a fire.
Solid bricks resist very well to fire, and they run the risk to vitrify and melt only if they have been exposed to high temperatures for a long time, but this is very unlikely.
On the other hand, hollow bricks crack after a short-time exposure to fire.
Concrete has a low thermal conductivity and it generally resists well to fire, but their surface flakes off so that the reinforcing bars are directly exposed to the fire.
The steel bars inside reinforced concrete crack when the temperature reaches 800°C.
When building steel is not protected, its fire resistance is divided by half, and it will crack at a temperature that is much lower than the one reached during a fire. Steel buildings tend to suddenly collapse in case of extreme temperatures.
Wood, against all odds, has a good fire resistance. The frames of buildings that are completely made of wood show a higher resistance, due to the creation of a charred exterior layer that protects the wood inside.