29
8.7
Pipe heights and mutual distances on a flat roof.
Height A
This is the height of the air inlet that must have a cap to prevent
rainwater entering the system.
When in- and outlet are mounted on a flat roof, the inlet should be at
least 60 cm above the roof surface and at least 30 cm above the max-
imum snow level.
Example 1:
When the maximum snow level on the roof surface is 45 cm then height
A should be 45 + 30 = 75 cm. This is more than 60 cm so this height
should be 75 cm.
Example 2:
When the maximum snow level on the roof surface is 15 cm then
height A should be at least 15 + 30 = 45 cm. This is less than 60 cm,
so the height should be 60 cm.
Height difference B
This should be at least 70 cm: the flue gas outlet should be at least 70
cm higher than the air inlet and should be equipped with a conical out-
let.
A single flue outlet on a flat roof should stick out at least 100 cm
from the roof surface.
Distance C
– mutual horizontal distance at roof level
This should be at least 70 cm.
