# Bath fan vent termination



## Inspector 102

Is there a required distance that a bath fan vent needs to be from an openable window. Under 2003 IRC, Section M1506 I am not finding anything to address it. Other than poor design, is there any code addressing this?


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## globe trekker

Inspector 102,

Not sure about the reference, but please refer to Section G2427.8, #3.

From the 2006 IRC:

*G2427.8 (503.8) Venting system termination location.*

The location of venting system terminations shall comply with the following

(see Appendix C):1. A mechanical draft venting system shall terminate at least 3 feet

(914 mm) above any forced-air inlet located within 10 feet (3048 mm).

*Exceptions:*

1. This provision shall not apply to the combustion air intake of a

direct-vent appliance.

2. This provision shall not apply to the separation of the integral outdoor

air inlet and flue gas discharge of listed outdoor appliances.

3. 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. The bottom of the vent terminal shall be located at least 12

inches (305 mm) above grade.

4. 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-inch (230 mm) vent termination clearance, and an appliance

with an input over 50,000 Btu/h (14.7 kW) shall have at least a 12-inch

(305 mm) vent termination clearance. The bottom of the vent terminal

and the air intake shall be located at least 12 inches (305 mm) above grade.

5. Through-the-wall vents for Category II and IV appliances and

noncategorized condensing appliances shall not terminate over public

walkways or over an area where condensate or vapor could create a

nuisance or hazard or could be detrimental to the operation of regulators,

relief valves, or other equipment. Where local experience indicates that

condensate is a problem with Category I and III appliances, this

provision shall also apply.

.


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## Papio Bldg Dept

Try 303.4 & 303.5 in the 2003 IRC.  You might be thinking of Appendix C, which is for IFGS exit terminals for mechanical draft and direct-vent systems.


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## Pcinspector1

That's were the vent should dicharge, one foot above the front entry door! Does'nt that pass the smell test?  

pu1


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## Inspector 102

Since this vent is not connected to a fuel burning appliance, I did not think that Section 24 would be applicable and the Section 1506 would apply. Again no reference to clearances since there is no hazardous exhaust (depending on appetite) being discharged.


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## Inspector 102

Section 303.4 does state not directed into walkways, but this is the back of the house, directly above an openable window. No does not pass the "smell test" but does not appear to be a violation.


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## Gregg Harris

Inspector 102 said:
			
		

> Is there a required distance that a bath fan vent needs to be from an openable window. Under 2003 IRC, Section M1506 I am not finding anything to address it. Other than poor design, is there any code addressing this?


There is no requirement for termination.


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## Papio Bldg Dept

Inspector 102 said:
			
		

> Section 303.4 does state not directed into walkways, but this is the back of the house, directly above an openable window. No does not pass the "smell test" but does not appear to be a violation.


As you noted, it stinks, but we can't regulate stupidity.  In our AHJ, we allow termination at the soffit vent, which pretty much guarantees being directly above an openable window.  For what it is worth, not many people open their windows anymore.


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## Pcinspector1

IRC2006 Sec

M1501.1 Air shall not be exhausted into an attic, SOFFIT, ridge vent or crawl space.

M1507.2 Exhaust air from bathrooms and toilet rooms shall not discharge into an attic, crawl space or other areas inside the building.

I'm with you Papio, let them discharge to the house soffit as long as they have soffit vents. Some builders in this area don't like the looks of soffit vents on the front of a house.

pc1 or pu1


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## Pcinspector1

Papio, were legal, see IRC2006, M1507.1 General


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## Francis Vineyard

Bath exhaust can terminate in the same locations as an operable window.

Francis


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## Papio Bldg Dept

Our AHJ 2006 IRC amendment:

*M1501.1*, Outdoor discharge. Change to read as follows: The air removed by every mechanical exhaust system shall be discharged to the outdoors. Air shall not be exhausted into an attic, soffit, ridge vent or crawl space.

Exceptions:

1. Whole-house ventilation-type attic fans that discharge into the attic space of dwelling units having private attics shall be permitted.

_2. Bathroom exhaust fans may be ducted through an exterior soffit, provided that the exhaust duct discharges through a soffit vent to the exterior._


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## Papio Bldg Dept

Pcinspector1 said:
			
		

> Papio, were legal, see IRC2006, M1507.1 General


interesting PC1.  That seems like a grey area when it comes to bathroom windows though...almost makes me want to use appendix C as standard to prevent recirculation?


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## Papio Bldg Dept

For those without the slightly above average book (italics are areas with black revision bar adjacent to):

M1507.2 Recirculation of Air.  Exhaust air from bathrooms and toilet rooms shall not be recirculated within a residence or _to another dwelling unit and shall be exhausted directly to the outdoors.  Exhaust air from bathrooms and toilet rooms shall not discharge into an attic, crawl space or other areas inside the building._


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## Moscow

When it comes to bath fans IRC took out the termination for them, however IMC 2009 section 501.2.1 note 3 it still has the 3 foot rule so here that is what we used for bath fans for all buildings.

Good Luck

Justin


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## Inspector Gift

Inspector 102,

Look at 2003 IRC, Sections R303.4 & 304.1 for the distance of openings from any "hazardous or noxious contaminant".  And then notice the paragraph that states toilet rooms and bathrooms and kitchens are not considered "hazardous or noxious".

2003 IRC

R303.4.1 Intake openings.

"Mechanical and gravity outdoorair intake openings shall be located aminimum of 10 feet (3048mm) from any hazardous or noxious contaminant, such as vents, chimneys, plumbing vents, streets, alleys, parking lots and loading docks, except as otherwise specified in this code.  Where a source of contaminant is located within 10 feet (3048mm) of an intake opening, such opening shall be located a minimum of 2 feet (610 mm) below the contaminant source."

"For the purpose of this section, the exhaust from dwelling unit toilet rooms, bathrooms and kitchens shall not be considered as hazardous or noxious."


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## Inspector 102

Moscow - unfortunately this state has amended that section out of the code and inserted (refer to 401.4.1) which again gives no distance. With this being a residential application, I could not apply that section anyway. Thanks for the input though.


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## klarenbeek

2012 IRC finally addresses this in section M1506.2. Bath fans will be 3 feet from property lines and  operable or nonoperable openings or 10' frommechanical air intakes


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