To begin calculate the portal of the firebox, that is the very furnace hole. Divide the amount of floor space to 50. Now the same amount divide by 70. Obtained two results are the maximum and minimum value of the square flue openings designed fireplace. For example, if your room is 10 square meters, the portal of the firebox shall be not less than 0.2 square meters.
Now calculate the height and width of the firebox of the fireplace. Consider these proportions: for small fireplace height relates to width as 2:3. That is, for your example, the portal of the firebox, with an area of 0.2 square meters, must have a 36 cm high and 45 cm wide.
Navigate to the calculate the depth of the fireplace. Keep in mind that this parameter is the most important because a large depth reduces heat loss in the room, and the small size of the depth causes the smoke.
Calculate the depth relative to the height of the portal. They should relate in proportion of 1:2-2:3. For your room 10 sq. m. the optimal depth of the firebox the fireplace will be in the range 18-24 cm
Count on the smoke hole of your fireplace based on the square flue openings. The smoke hole is recommended to be reduced to 8-15 times, starting from square portal. So in a room with an area of 0.02 square meters, flue brick chimney of the fireplace are built in sizes from 14x14 to 14х27 see If you plan to use the fireplace the chimney with round chimney, you must ensure that its diameter is from 8 to 14 cm.
Proceed to calculating the size of the fireplace. At the same time calculate how much this project you will need bricks. Keep in mind that brick has a standard height - 6.5 cm, width - 12cm, length - 25 cm Width of the seam masonry brick is about 0.5 cm Parameters of the future fireplace for your room area of 10 square metres would be: - combustion chamber of a width of 53 cm, because 2 bricks will include;
- height 38.5 cm, because it will be 5 rows of bricks;
the depth of 1 brick;
- chimney - 14x14 cm