User blog:Holroy/Fire spreading


 * In this blog I'll cover the area of how far fire will spread over air, stone and into wood. 

I created a lot of dangerous situations in creative world, and set stuff on fire. The general setup was to use Netherrack as the fire, cobblestone as the fire preventer, and the wood block to be set on fire. In the image, all wood blocks which has burnt up has been replaced with redstone blocks, and some blocks of air has been replaced with glass blocks.

The short answer to the distance where blocks will catch fire is all blocks surrounding the block on fire, and if next to a wall a up to four blocks in the wall.

Distance 1 block horizontally
In the left of the image, you'll see various test configurations with blocks in the square around the block on fire, and blocks one above the fire, and one diagonally above the fire, and on top of non-flammable blocks. All wood blocks caught fire with this distances.

Distance 2 or more Blocks horizontally
In general this seems safer, as shown in the middle three columns in the lower part of the image, as none of these wood blocks caught fire.

However, there is one vital exception shown above the line of fire to the right. If the wood block was a level above the block on fire, wood blocks 2 blocks away (that is with one block of air between the fire and the wood) would catch fire.

Going vertical
As it caught fire a block above with one block of air, I devised more tests going mainly vertical. These are shown in the top part of the image, on the left with the wood block directly above, and on the right with a simulated wall behind.

The result are that with a wall behind, you'll have to have at least 4 non-flammable blocks before something flammable. Directly above the fire, you'll need at least 5 blocks (to be on the safe side) including the block of air where the flames are dancing.

This distance can of course be limited by placing a roof over your fireplace.

Intensity of multiple blocks on fire
Whether blocks catch fire or not around a block on fire, does depend a little on probability, so if multiple blocks are set on fire, and there are other flammable blocks the fire will spread faster. But it doesn't seem like it will spread any further. This is shown in the line of fire to the right. The fire never jumps across the one (or two) block gap.

Similar in the upper left, there are some test configurations with originally multiple wood blocks, and when these caught fire some of the surrounding blocks also caught fire for a while. But none of the nearby Netherrack caught fire and remained on fire.

The safe fireplace
The safe fireplace, as shown in the top and middle of the image, has a surrounding border of non-flammable blocks with a wall of non-flammable blocks for at least 4 high behind the fire. The roof should be, if made in flammable blocks, at least at the 6th block above the floor. If you want the roof lower, you'll need to make it similar to the border around the fire in non-flammable blocks.