Number 3 is a vent for an attic space called a roof vent or turtle vent.
Minimum clearance on roof vent.
To a height of only 2 in.
1 5 feet above the roof surface.
Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space.
Vegetation must not be allowed to grow within 3 feet of an exhaust vent.
The minimum clearance from combustible materials is generally 3 inches.
It may be difficult to tell the difference between type l and type b vents because they are made from similar components but the vent type should be clearly printed on the vent.
Cliff help me out if i ve misunderstood but it seems to me that b vent clearance requirements or gas heater vent clearance requirements that specify distance to nearest combustible are based on possible temperatures involved and thus on the input btuh of the equipment.
Does type b gas vent have a fire rating.
Number 2 is a vent for an exhaust fan like those found in bathrooms and laundry rooms.
These minimum clearances apply to unlisted single wall chimney and vent connectors.
The vent opening must communicate with outside air over an area no less than the area of the vent pipe measured on the inside.
Exhaust vents must be protected against rain and equipped with back flow prevention features e g flap dampers.
2 0 feet above the roof surface.
Stack vents may give off sewer gas so they should not be located within 3 feet of an operable window.
1 0 foot above the roof surface 1 7 12 to 8 12.
Roof pitch rise run in inches.
Purlins may not be necessary if the roof slope is 1 6 or more provided that the roof framing members run in the same direction as the roof slope each joist space is separately vented and that a minimum clearance of 63 mm is maintained between the roof sheathing and the top of the insulation.
Type b gas vent requires a minimum of one inch clearance to combustibles.
Type l vents should not be used to vent coal or wood fired appliances.
Exhaust vents must not be allowed to be obscured or hidden by vegetation.
2 5 feet above the roof surface.
On 2020 01 04 by mod b vent clearance to combustibles.
This one inch is a typical clearance for all brands of type b vent but each section of vent pipe is marked with the clearance required by underwriter laboratories so it should be checked.
They exhaust moist air to the outside.
Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge.
Reduction of required clearances is permitted as in table m1306 2.
When listed type l vent piping is used the clearance shall be in accordance with the vent listing.
But then i already knew that.
The vent when protected from snow closure by the panel design can be cut down from the minimum height of 6 in.
