This will prevent the 'chimney effect', and thus safer in case of a fire.

Shane lectured them: "One problem is the chimney effect.

The edifice, furthermore, different from the traditional skyscrapers, produces a chimney effect, un-polluting the air at ground level.

Air travels through the holes to all the briquettes, creating a "chimney" effect.

The resulting convection causes air to rise up the tower by the chimney effect.

The entrances and tunnels were dug at the same level of the natural opening, which prevents air from leaving the cave in a chimney effect.

Also, he said, some sidings create a "chimney" effect if there is a fire, causing the fire to spread quickly up through the building.

The smell is carried upwards by the chimney effect and flies are prevented from leaving the pit and spreading disease.

A draft rising between the cover and the lining adds to the chimney effect and helps carry the smoke up and out.

"This creates a chimney effect, by drawing warm air from the inside of the building," Mr. Anderson said.