A category i vent system works by allowing heated flue products to rise vertically so the vent pipe must rise vertically from the boiler vent connection as soon as possible.
Boiler vent heighy over roof.
1 0 foot above the roof surface 1 7 12 to 8 12.
Vertical flues the majority of boiler flues exit out of a wall horizontally but if the flue from your boiler comes out at roof level then there are also some regulations that.
This is because the waste generated by combustion can include dangerous gasses like carbon monoxide so you don t want that waste gas too close to an opening.
Depending on the size of the boiler the flue must be positioned a certain distance from the nearest window door or air brick typically this is around 30 60cm if it s to the side or above the opening and a bit more if it s below.
Table of rooftop chimney clearances for metal b vent chimneys flues.
Chimney height may need to be increased by 2 3 per 1000 feet of elevation although added height generally equates to stronger draft there is a point where the system can become too long and over drafting might occur causing increased fuel consumption hotter burn temperatures and damage to your appliance.
Minimum height above the roof surface 1 flat to 7 12.
Gas vents 12 inches 305 mm in size or smaller with listed caps shall be permitted to be terminated in accordance with figure g2427 6 5 provided that such vents are at least 8 feet 2438 mm from a vertical wall or similar obstruction.
You should also limit the length of the horizontal flue pipe.
Roof pitch rise run in inches.
1 5 feet above the roof surface.
Securing any joints with brackets will help to ensure your flue can withstand people banging a suitcase or accidentally knocking it without wobbling or coming loose.
In all areas exhaust vents should be at least 1 foot above roof surface.
You see if you ve got a boiler in your attic and the flue goes through the roof there s a chance it could get bashed or pulled on accidentally when you re up there.
300 mm below above or alongside an opening window air vent or other ventilation opening 75 mm below guttering drain pipes or soil pipes 200 mm below eaves roof overhang 300 mm above ground roof or balcony level 2000 mm below a velux window for a vertical flue 300 mm above roof pitch or flat roof for a vertical flue.
Exhaust vents must not be located where they might be obstructed by drifting snow consult local experience as to the height of snow drifts against buildings.
2 5 feet above the roof surface.
If your boiler flue has to face out onto a public space the installer will have to ensure that it s fitted at least 2 1 metres above ground level over head height.
2 0 feet above the roof surface.
All horizontal runs of vent pipe must rise 1 4 inch per foot of run to maintain proper draft in the vent.
