Distance from windows and doors The exact distance will depend on the size of your home but, generally, the regulations prevent a boiler flue from being situated within 30-60cm of a window or door. This is to prevent harmful gases from exiting the flue and then re-entering the property through an open door or window.
The exhaust terminations that penetrate through the exterior walls or roof will need to be located 3 feet (914 mm) from windows that are providing the natural ventilation to the dwelling unit.
Typically, the distance is 12" minimum from a window for a direct vent unit and more for mechanical draft systems. Check the manufacturer's installation instructions.
If you have an openable window in your roof and the flue will be within 2300mm either side of it or anywhere below it, then your flue system must rise above the window by 1000mm.
The boiler flue terminal should be positioned away from doors, windows or other openings. There should be a space of at least 300mm above, below or to the side of any opening.
The positioning of the flue needs to be (a minimum of): 300 mm away from an opening window or air vent. 25 mm below guttering, drain pipes or soil pipes.
Double wall flue pipes have to be installed in accordance with the manufactures installation instructions. ( generally clearance to combustibles is 6 inches. ) Single wall flue pipes have to comply to CSA B365 requirements. ( generally clearance to combustibles is 18 inches. )
This rule means that your chimney's shortest side needs to be at least 3 feet above the roof penetration, and its top has to be 2 feet higher than any part of the building that's within 10 feet.
Regulations for the Chimney
The flue must be at least 4.6 meters in height from floor level and must be kept away from any windows or doors.
Taller Chimneys Produce Stronger Draft
A rule of thumb for minimum height states that the total system height (from the floor the appliance is mounted on to the top of the chimney) should never be less than 4.6 m (15 ft.).
Each vent shall terminate not less than 10 feet (3048 mm) from, or not less than 3 feet (914 mm) above, an openable window, door, opening, air intake, or vent shaft, or not less than 3 feet (914 mm) in every direction from a lot line, alley and street excepted.
Regulations require the flue to be: 300mm away from any openable window or vent. 300mm away from any door.
The vent terminal of a direct-vent appliance with an input of 10,000 Btu per hour (3 kW) or less shall be located at least 6 inches (152 mm) from any air opening into a building, and such an appliance with an input over 10,000 Btu per hour (3 kW) but not over 50,000 Btu per hour (14.7 kW) shall be installed with a 9- ...
Vent Terminal Clearances
The vent must terminate at least: One foot from windows and doors. Three feet from inside wall corners.
A fan should always be sited in the furthest window or wall from the main source of air replacement to avoid short-circuiting the airflow. It should be located as high as possible in the window or wall nearest to smells or steam, but not directly above eye-level grills or cooker hoods.
VENTING REQUIREMENTS
Single wall metal venting must have 6” clearance to combustible materials. Double wall B-vent material must have 1” clearance to combustible materials.
TYPICAL INSTALLATION OF FIRE PLACE FLUE INSERTS
There must be a clearance of 50 mm between the outer flue and adjacent materials.
The specific minimum distance required can vary depending on the heat emission of the fireplace, as well as the type of materials used in the construction of the furniture and the surrounding area. Generally, a clearance of at least 36 inches is advised to allow for proper airflow and reduce the risk of overheating.
The primary goal is to help you avoid creating unsafe situations that can result in a fire burning your home and possibly causing the loss of life. The National Fire Code dictates that any combustible material (e.g., wood mantel or similar trim) must be at least six inches from the firebox opening.
The flow area of the largest common vent or chimney shall not exceed seven times the area of the smallest draft hood outlet. Typically: many water heaters use a 3" flue, the largest area to connect the water heater should be 49" in area or an 8" x 8" chimney tile or 7" round chimney.
Headers, beams, joists, and studs shall be at least two inches from the outside face of a chimney or from masonry enclosing a flue. Trimmers shall be not less than five inches from the inside face of the concrete or masonry chimney wall. Finished flooring shall have at least one-half inch clearance from chimney walls.
Explained, the chimney pipe must be a minimum of three feet above the roof but also two feet taller than anything within ten feet. The portion of the rule stating the pipe needs to be 2 feet above anything within 10 feet is where most people get confused.
Flue Pipe Clearance Requirements
Your flue pipe needs proper clearance from combustible and non-combustible materials for safety. You'll need at least three times the pipe's diameter for clearance from combustibles.
No vent terminal shall be located directly beneath any door, window, or other ventilating opening of a building or of another building, nor shall any such vent terminal be within 10 feet horizontally of such opening unless it is at least 2 feet above the top of such opening.
Single skin flue pipe - distance to combustibles
For example a 125 mm single skin flue pipe must be at least 3 x 125 mm = 375 mm from combustible materials (being pedantic the actual figure is a little higher as 125 mm refers to the internal diameter not outside diameter).