ECN Forum Forums Code Related Discussion Building Codes for Electricians Residential Venting

Larry, you are absolutely correct....next, you'll be telling us that these are also called "fard fans", from the French "Fard", which means 'to apply make-up."

I'm thinking the requirment for my state is the fan must be switched with the light. Something about not switched seperatly because of the noise involved, it would not get used. I have found many just vented into the attic.

I prefer separate switches so the fan can/wll be used without, or leaving on after, turning off the light.

Many bathroom fans here use a built-in timer so they turn on with the light and switch off a few minutes after the light goes off. The time delay is usually adjustable from a couple of seconds to sevreal minutes.

Personally, I prefer the fan to be on its own independent switch.

Paul, you can also buy a single switch with two load wires that does the same thing: light off immediately, fan off after 10 minutes (or adjustable, I don't remember).

If it was my house, I would never vent to the attic..........

Good Day!

Here in Maple Ridge, the bath fan must be vented to the out side, and the 14/2 must be run directly from the main bath fan directly to a relay in the furnace with a time clock on it so that when the furnace motor comes on (LOW) for the CFM required air exchanged, the bath fan must also come on with it, and is to be connected to the time clock as so that the fan is over ridden by the blower (LOW) motor on an 8 Hrs on, 8 Hrs off cycle for the fan, and wired so that it can not be over ridden any other way, so you have no choice but to install a relay before the time clock to isolate the furnace motor, (LOW) and the bath fan, so the motor can’t back feed the fan and blow the PCB in the furnace it self.
We have argued up and down that this should not be done by us, but the furnace installation company, and that by our cutting into the low speed motor circuit and adding that iso relay, that it is now considered not to be SA approved any longer and warranty issues, as the circuit board has now been altered, oras per the “ALTERATION of EQUIPMENT” rule.

The inspector here also looks for an extra wire run in the attic and left by the 1 gang box, so when the final has passed, the home owner wishes for us to remove the 1 Gang or 2001, and replace it with a 2002, 2 Gang and put the over ride switch in it like it used to be in the 90’s (WHICH I WILL NOT DO PERIOD), forif you are caught, you’re license is suspended, but I feel for the home owner as that fan will drive you crazy if it is near the master bed room(AS WHEN ALMOST IS IT NOT?) and is cycling at 2:30 in the morning even, the low sone fans, but them’s the rules here in Maple Ridge, and Coquitlam areas.
I do not know if that part of the building code is enforced anywhere else, but if anyone knows, I wish they could post it, as I would greatly appreciate it just to keep up with things!

Have a good day!

Robert Wagner!

To summarize the vent codes:

IRC 2003 R303.3 Exception requires ventilation air from bathrooms be exhausted directly to the outside.
IRC 2003 M1501 requires clothes dryers to exhaust outside the building.
IRC 2003 M1502 prohibits range hoods from terminating in the attic.
- none of these have changed from IRC 2000, though the cfm requirements section is annotated as having changed. (Intermittant 100cfm for kitchens and 50cfm for baths in 2003)

Watch the UL listing on the bathroom fan duct, too- "air connectors" (as usually used for bathroom fans) are limited to 14', while "air duct" can be unlimited length.

[This message has been edited by SteveFehr (edited 10-22-2006).]

When we bought out house, the inspector noticed mold in the attic on the underside of the roof sheathing. Luckily it wasn't one of the nastier strains, but we wound up having the roof replaced (needed new shingles anyway) as part of a non remediation "remediation".

The HI thought it was due to the soffit vents being covered by blown in insulation and the venting of the bathroom fan directly into the attic space.

In northern minnesota if you vent into the attic it will turn to frost in your attic and when it gets warm your cieling and insulation is going to get wet and could mold and just cause problems that a vent to the outside would prevent.