Ducting, Air Circulation and Ventilation Systems - Not Approved By Code

Hello,
I just learned that my vent duct hookup for my basement bathroom and gas dryer are not code approved and that both should have their own vents. The ducts from both lead to a wye fitting before exiting the dwelling. First, I would like to know why this is not approved. Second, I like to know if its ok to vent the bathroom by going through a partition wall into a garage which is used for tool storage and workshop. Then the moisture and stale odors would leak out through small openings around the garage door. The garage demensions are 9 foot wide by 11 foot by 7 foot high and is just below the kitchen area. I looked at my options and this seems the easiest way to go. I also can run duct to the outside (with a bit more work) but I need to break into part of a block wall which already has a hollow space in it and use it as a duct to the outside. My house is a row dwelling so my choices are limited.
To make it a bit clearer, I would need to run duct against the block wall until I get to the last cement block and then make a hole. Then from outside, I would chisel out some of the block to reach the hollow space in the block. The airflow would run the length of the block.Then I can attach the duct to the hole and place a vent cover on the outside wall.

The "why" is easy, it is because a gas dryer produces carbon monoxide and with the combined system it is possible for that carbon monoxide to enter the living quarters. It also will restrict either or both exhausts if both are operated at the same time and that is a reason that it is also not acceptable with an electric clothes dryer.

Venting into the garage is also a poor idea as the high moisture level will promote rusting of your tools and will set up a dandy environment for all kinds of pests including wood destroying bugs and rodents.

Neither can you use a hollow block passage as part of a duct. You will need to run duct through that hollow space. Furthermore, clothes dryers have a maximum developed length of duct that they will be able to vent into without the use of a booster fan. Longer (or too small a diameter) ducts on bathroom exhausts will lessen the airflow from the exhaust fan.

Furd,
Are you tradesman in the ventilating field because I want to question your responce. The home centers sell those diverter valves to send heat from the gas dryer back into the room. So how do you reconcile your statement about carbon monoxide and the use of diverter valves? To my knowledge, I don't believe they have been banned.

I can use the existing vent for the dryer. So thats not a problem. But working out a solution to vent my basement bathroom will be a challange. I have two choices:
I can take out the block and place a short length of 4 inch duct in its place. The block is not a whole block. Its about halfsize. Probally not more then 4 inches in depth. The cement block wall separates my garage from the utility room where both ducts are presently located. So I would need to find something to dress up the space around the 4 inch duct. I could probally put some panning material on both sides of the wall.
Or go back into the joist area where the original vent for the dryer is and use that for the bathroom vent, But the catch is:
This area has been panned over to use as a return heat and air cond. duct and making a hole in it to install an elbow and short length of duct in the joist area will cut down on the return air flow some. I think I am stuck between a rock and a hard place.

The original vent is no longer used and is block off with insulation. The hole for this vent is just above the joist area.

I also want to add that this panned area for the heating and air cond. return is the smaller of two returns. So it maybe it will work if I install an elbow and short length of 4 inch duct in that area. What do you and others think about this so far?

Are you tradesman in the ventilating field because I want to question your responce. The home centers sell those diverter valves to send heat from the gas dryer back into the room. So how do you reconcile your statement about carbon monoxide and the use of diverter valves? To my knowledge, I don't believe they have been banned.

Nope, I'm a retired engineer that worked with commercial and industrial sized HVAC among other things.

Just because the home centers sell something does not mean it is approved for use in all areas and under all conditions. The employees at those same home centers give out an awful amount of advice that is just plain wrong. Furthermore, I think if you were to carefully read the instructions for those "diverter valves" you would find that they are not for use on gas-fired dryers but only for electric dryers.


I'm having trouble visualizing what you are trying to describe. Is it possible for you to post a few pictures? Pictures need to be uploaded to a photo hosting site and the URLs posted here.

I took another look at my present setup and realized that I could also hire someone to drill out another hole either above or below the the one that is presently being used. That appears to be the easiest solution. For the life of me, I don't know why I did not think of it sooner.

I'll check the web for a photo posting site. If I have difficulty, I can always post some pictures on my web site.

Furd,
I had to post pictures on my website.
http://mysite.verizon.net/vzeqx2eq/mysite/

I believe you will agree that the best solution would be to drill another hole through the wall near the one shown. When I was looking for other ways to run the bathroom duct, I was looking for a way to shorten the run plus eliminate an elbow or two. It appears that Idea will not work out. If you look at the ceiling area, (its not too clear) you will see that it is panned off and above the panning is the original vent which is no longer used.