Vent Termination must be at least 9" from windows, doors, or any other opening through which flue gases could enter the building. 12" for more than 50k btu.
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.
A mechanical draft venting system, excluding direct-vent appliances, shall terminate at least 4 feet (1219 mm) below, 4 feet (1219 mm) horizontally from, or 1 foot (305 mm) above any door, operable window or gravity air inlet into any building.
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.
Vent Termination must be at least 9" from windows, doors, or any other opening through which flue gases could enter the building. 12" for more than 50k btu.
The exhaust pipes of soil suction systems must vent above the surface of the roof and 10 feet or more above the ground, and must be at least 10 feet away from windows, doors or other openings that could allow radon to reenter the home, if the exhaust pipes do not vent at least 2 feet above these openings.
The vent terminal shall be at least 4 feet (1219.2 mm) below, 4 feet (1219.2 mm) horizontally from or 1 foot (304.8 mm) above any door, window or gravity air inlet into the building.
Liquid fuel normal vent pipes shall terminate outside of buildings in a nonhazardous location at a point not less than 2 feet (609.6 mm) measured vertically or horizontally from any building opening and not less than 2 feet (609.6 mm) nor more than 12 feet (3657.6 mm) above the fill pipe terminal.
An open vent terminal from a drainage system shall not be located directly beneath any door, openable window, or other air intake opening of the building or of an adjacent building, and any such vent terminal shall not be within 10 feet (3048 mm) horizontally of such an opening unless it is 3 feet (914 mm) or more ...
According to Home Inspection Insider, floor vents need anywhere from six to 12 inches of space in all directions to ensure airflow. Your floor vent needs space on each side and overhead. Allow a minimum of six inches on top, and consider the direction of slats or louvers on your vent as well.
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.
Section R303.
When a community adopts this section, it essentially says that bathrooms must have open windows for venting purposes. The code reads that the window must have an "aggregate glazing area...of not less than 3 square feet (0.3 m2), one-half of which must be openable."
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.
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.
Regulations require the flue to be: 300mm away from any openable window or vent. 300mm away from any door.
Vent Terminal Clearances
The vent must terminate at least: One foot from windows and doors. Three feet from inside wall corners.
Air admittance valves can be installed externally, but this is not very common and is usually only done if the soil pipe is too close to an opening window. Open pipe outlets must be installed more than 3 metres away from a window that opens, but air admittance valves can be closer than this.
For a 1 ½-inc pipe the vent should be 42 inches away at the most while a 2-inch pipe must have a maximum distance of 5 feet. For pipes that have a diameter of 3 inches the distance is 6 feet and for a 4-inch pipe the most it should be away from the vent is 10 feet.
For all environmental air exhaust: 3 feet (914 mm) from property lines; 3 feet (914 mm) from operable openings into buildings for all occupancies other than Group U, and 10 feet (3048 mm) from mechanical air intakes.
Exhaust ducts should always terminate outdoors (refer to applicable codes for vent termination clearance requirements). Running exhaust ductwork up to a vented attic or just in front of an attic vent (gable, ridge, or soffit) is not sufficient. The exhaust should be fully ducted to a point exterior to the home.
If the manufacturer's instructions do not specify a termination location, the exhaust duct shall terminate not less than 3 feet (914 mm) in any direction from openings into buildings.
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.
906.2 Clearance. 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 direc- tion from a lot line, alley and street excepted.
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.