make-up air and propane hoses

carolinainmymind · #1 2011-01-28, 11:38am

I'm starting to plan/ build a new workspace in the end of an outbuilding. I'm planning for ventilation up and out through the roof or gable end. For make-up air, there is an existing (dryer vent) hole at ground level. They will be almost in line with other, but about 12' apart, vertically. Is this OK?

And can I run my propane hose in through the same hole as my (ducted) make-up air? It's a brick building, so the fewer holes I have to make, the better. Thanks for the advice!

laserglass · #2 2011-01-28, 1:33pm

your make up air duct MUST be larger than you vent duct diameter. for example, if you have a 6 inch ventilation duct going out, then you should have and 8 inch duct for make up air. other things in your home may require make up air like furnaces, water heaters, cloths dryers... having a larger make up air duct eliminates any possible back flow under normal conditions. your propane tanks CANNOT be located near your inlet for your make up air duct. it is possible that leaked propane could get sucked into your make up air duct and bring it inside.

carolinainmymind · #3 2011-01-29, 6:46am

Nothing else in the shed, just l'il ole me and my cricket. An electric heater in the winter. I'll have to measure the hole, I think it may need to be enlarged. I had not thought about leaked propane (duh!), I was more concerned about flashback in the hoses. Thanks!

cheng076 · #4 2011-01-30, 10:13am

If the building is brick and the gable ends have brick extending to the peak of the gable might I suggest that you use one or two of the rafter spaces between the top of the brick wall and the actual roof to run your exhaust ducting. Unless, of course, you have no qualms about cutting into/thru the walls of the out building. It should also be possible to put a louvered opening in the entry door or in a window for makeup air. Post some pics and keep us posted on the project.