Thread: Garage ventilation system

Is there a building for self built garage ventilation?

Here is the situation. A home owner garage was very hot and also humid after a raining. He bought a bathroom ventilation fan, a fire safe aluminum duct tube (same one's you use for the dryer), and a vent hood, like the vent for the dryer.

The bathroom ventilation fan is mounted on the top end of the garage. The fan is turn on and air in the garage is taken from the garage, into the fan, pushes out to the aluminum duct tube, out to the vent hood and the hot air and humidity is outside.

Is there any code against this setup?

Thanks,

Hankd88

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Any Code against this set-up? Probably a few.
The two simplest would be electrical conditions and whether the unit is rated for exterior use.

A simple roof mounted exhauster would have been a better choice, thermostatically controled.

What is the source of the fan's make up air?

Originally Posted by Michael Thomas

What is the source of the fan's make up air?

This was my first thought as well, also, I have never seen a bath exhaust fan that would move enough air to cool a garage.

To me this sounds like something that is in the planning stage.

Originally Posted by Markus Keller

Any Code against this set-up? Probably a few.
The two simplest would be electrical conditions and whether the unit is rated for exterior use.

what electrical conditions are you referring to? the unit is still inside, it is just unconditioned space. do receptacles and light fixtures in a garage need special ratings for the conditions?

Originally Posted by Michael Thomas

What is the source of the fan's make up air?

calculate the infiltration in area around a garage door, more than adequate make up air. installation sounds acceptable to me!

My 1969 house has two foundation vents in the garage area. It also has a gas furnace in the garage area. I'm not sure if one is related to the other.

Electrical conditions - considering the rest of the install sounds like DIY nonsense, I'm GUESSING the electrical work isn't any better or safer. Did the guy run pipe, greenfield, romex, an old extension cord that was lying around, two bare wires from the hardware store? How are the feed, box and switch installed?
I wouldn't be surprised if it were non-compliant.
Based on the OP you think the install sounds acceptable? Really sorry to hear that.

No, No, AD. Look at post #6 by Brian. My post is directed at him.
Markus

Most bathroom fans only move between 50 and 100 cfm. With that in mind this set up would be the equivalent of a fart in a windstorm.

Originally Posted by Markus Keller

No, No, AD. Look at post #6 by Brian. My post is directed at him.
Markus

get over yourself! i know if it is not in conduit and installed by union members it is just so california!

Originally Posted by A.D. Miller

Agreed.

bushes and barton?

Too much effort has already been put into discussing this non-issue, but I will add my 2 cents.

The installation is fine, make-up air is not a concern due to the size of the garage door opening, and depending where you are located, romex is acceptable for wiring.

Effectiveness may be better than suggested above. It won't keep the air cool but will help in humidity control if left on constantly. Code requires 0.05 CFM/Sq. Ft. of mechanical ventilation IF there is inadequate exterior wall openings. So even though the fan is not required by code, it will move more air than if it were. Sorry that's a little run around.

Originally Posted by Rod Butler

Too much effort has already been put into discussing this non-issue, but I will add my 2 cents.

The installation is fine, make-up air is not a concern due to the size of the garage door opening, and depending where you are located, romex is acceptable for wiring.

Effectiveness may be better than suggested above. It won't keep the air cool but will help in humidity control if left on constantly. Code requires 0.05 CFM/Sq. Ft. of mechanical ventilation IF there is inadequate exterior wall openings. So even though the fan is not required by code, it will move more air than if it were. Sorry that's a little run around.

finally, someone else who knows whats right

Originally Posted by A.D. Miller

The installation is "fine", and so is the "reasoning" ability of anyone who thinks it is.

??

Originally Posted by A.D. Miller

The installation is not "fine", and neither is the "reasoning" ability of anyone who thinks it is.

Wow looks like you need to justify your position by making it personal, sorry to hear that.

From the original post I gathered that the fan exhausted out the end of the garage to the outdoors. You seem to have understood it to say that the duct penetrated the wall of the living space and added all the verb about the duct construction.

Not sure which of us understood the post the better but I still think the installation is fine.

Okay. Thanks to everyone who replied. I do agree with this being up to code. The fan may not be adequate in terms of keeping the garage cool, but it does cause a movement of air.

As for the explanation of why it's not up to code is not logical. The exhaust fan is placed on the inside of the side wall of the garage. The fan pulls the air out of the garage, not pulling air into it. The air is then pushed out to the aluminum duct to a vent hood that is on the side wall of the house.

So here is the logics of the air flow:

Remember the air is taking out outdoor and not into any living space - The logic is below and the arrows shows how the air will go ---

Inside garage ---> Exhaust fan ---> aluminum duct hose ---> vent hood ---> Outdoor

Garage Fan. Tamarack Dragon Air Exhaust Garage Fans.
Quiet Cool Garage Fans - Ventilation and Exhaust Fan
Garage Ventilation - Garage Improvement

All these products are exactly what the homeowner setup, but the usage of a bathroom exhaust fan is weak, but there is no code violation since the system that he built is not connected to any internal ducts nor does the system push the garage air into any living space that can cause carbon monoxide into living space. Instead the system is a separate system that is placed on the side of the garage pulling the hot air from the garage and then pushing it outside to the great outdoors. The question about where is new air coming from? That is a good question, if you notice the garage when all the lights are off, you will notice that the garage is not fully sealed. Sealing the garage completely is a no no due to yes you guess it, carbon monoxide. The CO2 has to have some place to escape. The system will help with that by pulling the CO2 from the garage venting it outside. Some new air are pulled from the cracks from the garage doors.

As for the electrical, why can't you hang an extension cord to power the exhaust fan? No code against that. The system can be connected to the house electrical system thus not needing a AC cord, and a train/certify electrician tech is needed for that. If the wiring with an extension cord or wired into the house electrical is against code, then the outdoor electrical outlets are not up to code. The outside housing lights are not up to code then.

I didn't want to cause any animosity as this was just to ask a simple question amongst my peers. I apologize if I did. But it does make me wonder and brings up some questions about when homeowners get an inspections, are they getting a qualify inspector that knows what they are inspecting, know up to date codes, and what they are talking about?

Wow, you are either completely full of it or the actual homeowner, not an HI. Since only municipal inspectors can legitimately make a final determination on Code compliance, Are you a municipal Code inspector?
You make so many assumptions in your post it is amazing. Since you seem to have 'determined' everything is just dandy, why bother.
- How long is that extension cord? Did 'they' cut the end off of the extension cord to tie it to the fan? Yes, now the cord is no longer being used under its' rated/approved purpose. How is that cord connected to the fan housing. Properly or just shoved through the hole?
- Is that fan rated for exterior use?
You seem rather testy about the answers you received. Is that because they aren't the co-signing BS you were hoping for?

Originally Posted by Markus Keller

You make so many assumptions in your post it is amazing. . . . .
- How long is that extension cord? Did 'they' cut the end off of the extension cord to tie it to the fan?
- Is that fan rated for exterior use?

Markus, I missed where he said that the extension cord end was cut off. I also missed where he said the fan was installed outdoors.

He didn't I am ASSUMING.
- A garage, at least around here, is typically considered an exterior type space since many do not have full or sufficient enclosure. Granted if it is a new garage it is probably very watertight but not necessarily weather tight. If it is an older garage ... well I think we know what those are like. I guess we could debate interior/exterior since it should keep the car relatively dry but I don't know anyone who considers a garage 'interior' space.
- I don't generally see bathroom X fans with plug-ins for extension cords. Interior bathroom fans typically have a 1/2 knockout for pipe or greenfield connectors. So it would seem logical to me (which you and I both know can easily be illogical) that he/they may have cut the end off the cord to attach it. Unless maybe they ran two wires to a receptacle through the knockout. I guess the possibilities are endless.

Everyone assumes so much, If properly wired and ducted the exhaust fan is fine ,tho it won't do much to change the environment it serves. If not we have covered all the reasons it is wrong,,New thread time.

That's where the problem lies. Assuming things. I clearly laid out everything, but you are too hard headed to understand. I only take your posting Markus in offense because you assuming too much without logically thinking about what is explain to you and you attack others with no remorse. I am not the home owner and I know a couple of city housing inspectors, and they said the setup was fine. If you check some of the bathroom vents, the fan/unit has a two prong AC end. No wire splicing is needed.

I think I'm done with this posting/thread and this site. It's disheartening to see some members here that think the world revolves around them. They don't look deeper into the installation and setup and assume everything and then say there's a code violation. If the world thinks and acts like this, we are in trouble.

Post what you may after this post. I will not be reading or coming back to this site. Sad, because there are really good people on this site.

I always have to love it when a guy spouts nonsense in order not to answer the questions that could provide actual information.
I must give hank credit though. Many of the bath X fans do have a two prong receptacle factory installed. However what he seems to either not understand or be more than happy not to point out is that those two prong receptacles are NOT for line voltage hook-up. The two prong outlets are factory installed for the short cord from the fan itself to plug-in. Power to the housing still comes through the 1/2" knockout.
I would be more than happy to apologize for my error if you would post a picture of a unit that has a plug-in for the feed.
Oh, wait that's right you aren't reading this.

Ha! Turned out to be a timely thread, just ran across one of these:

Garage Through The Wall Ventilation Kit - Garage Ventilation

I'd be interested in the UL listing and testing of the "fire doors" on this unit and peoples take on this from the link MT provided.

GF-14 Garage Cooling & Ventilation System - Free Shipping - Garage Ventilation

Thanks for the link AD, their FAQ section yeilds:

14. Garages are fire rated. Does the GF-14 keep this fire integrity intact?
A. The GF-14 Garage Fan is equipped with a fire damper that is held open with a 212 degree fusible link to allow the air through the fan. In case of a garage fire this link melts and closes the damper keeping the flames out of the attic for up to 3 hours. Also the GF-14 Fan motor shuts off at 185 degrees.

I'm not seeing an exception in the IRC to allow the penetration of the separation at the garage ceiling even though they claim "UL listed components" and "fire damper"
Seems counter intuitive to pump garage fumes into the attic under pressure and hope it does not enter the house through combustion air vents or other openings as well as hoping the fusible link will close even while being cooled by exhausting air... Seems there would have to be UL listing of the entire device and a specific allowance of such devices in the IRC.
Am I wrong? What say the AHJ inspectors here?

A fire damper would only be required where ever the garage attic shares space or venting with the main house. By design the garage is a seperate entity. Fire dampers are only required in a 2 hour wall.

Originally Posted by David Bell

A fire damper would only be required where ever the garage attic shares space or venting with the main house.

Almost all, probably 'virtually all' ('virtually all' allows for the rare exception to this), attached garages share the same attic space and venting with the main house, otherwise one one need to continue the garage/house wall all the way to the roof sheathing.

Aaron is correct in that exhausting into the garage attic will pressurize "the attic" and force some of that air into the living space, which is something one would not want to do for many reasons, just like one would not want to even have an exhaust fan pressurize the attic and force outdoor air into the house from the attic. Doing so using garage air just makes the problem potentially worse.

By design the garage is a seperate entity.

Detached garages are a separate entity, attached garages are not, all they have is a "separation wall" (which is NOT a "fire wall") between the garage and the living space, and the attic over the garage is the same as the attic over the living space.

Fire dampers are only required in a 2 hour wall.

Incorrect. ANY fire-resistance rated wall would require a fire damper for a duct connecting one side of the fire-resistance rated wall with the other side of the fire-resistance rated wall, whether that duct was through the wall or around the wall (the duct would allow breaching the walls fire-resistance rating through the opening in the duct). The exceptions would be when the duct is within its own fire-resistance rated chase.

This applies whether the wall is a 2 hour wall, a 1 hour wall, or a 30 minute rated wall (which is constructed just like a 1 hour rated wall, this just allows for a lesser rated door in it that in a 1 hour rated wall).

A 1 hour wall requires fire stopping around a minimum 26 gage duct penetration.

Originally Posted by James Risley

Yes Dave, but if you were in the garage when it was on it would be the equivilent of being upwind of the fart.

Actually a 100 CFM running continuously in a two car garage can earn you 1 LEED point. In this case its more to prevent fumes from the garage entering the house than it is to cool. Though I think a 100-150 CFM running continuously would make the garage significantly cooler. In fact I don't think I'd want a several hundred (or a thousand) CFM fan in my garage unless it had a speed control. While my garage isn't heated, it is a few degrees warmer than the outside, during a Wisconsin winter.

If you do the math an average 3 car garage is 24X36X12 or roughly 11,000 cubic feet. with a 150 CFM fan (highest standard bathroom fan you can get) you are looking at about 1 hour and 15 minutes to do a complete air exchange. Again, this is on par from what you would want out of a hole house HRV/ERV.

You need more than fire rated ductwork. Several posters have stated that as long as you use the proper gauge ductwork. However, those codes are for only ductwork going through a firewall on there way somewhere else (ie not terminating). If you are going to install a bathroom (or any other) ceiling exhaust fan you either need a fire-rated model or need to purchase a "radiation damper" with a 3 hour rating. A radiation damper will set you back around 60 bucks. You should also have one on any makeup air ducts you install (which I'd recommend, you don't want backdrafting) these can be anywhere form 40-60 bucks as well.