gas water heater in shop

[adambaum]

We're contemplating moving and for some reason all the houses we are looking at have gas water heaters.  Since the garage = my shop, should I be worried about wood dust starting a fire within the water heater?  What about standard finishing fumes?  I try to do most of my finishing with the garage door open, but if it is later at night or windy, the door remains closed.

Adam

[Ronn W]

For solvent base finishing - Definitely an explosion hazard.  It is hard to say how dense the fumes have to be, depends on the solvent.  Gasoline fumes stay low near the floor - not sure about other solvents.  I would not risk it.  That said, I don't think there is a problem with water based finishes. As for dust... The air has to be pretty thick with dust before it can ignite.  The finer the dust the easier to ignite it.  You also have the concern of dust buildup on surfaces near the flame (just like every other surface in the shop.  I know that I would not be diligent enough to clean those surfaces often enough. 

[wdwerker]

My new gas water heater has a sealed combustion chamber with one of those push button spark igniters . I think it draws air from the double wall flue. It is also 16" off the floor with a drain pan.

[Beechwood Chip]

I think before the fumes get thick enough to explode, they are going to be doing bad things to you.  You need ventilation if you are working with non-water based finishes.  If you have adequate ventilation, then the hot water heater won't be a problem.

I wouldn't worry about sawdust at all, unless it was piled up around the hot water heater.

If you set up an exhaust fan for finishing, or if you vent your dust collector outside, then you need to provide some way for replacement air to get into your shop.  Otherwise, the replacement air will come down the flue, and will bring the combustion gases from the heater with it.

 

[Chestnut]

You guys need water heaters in AZ? I thought your water heater was just a garden hose on the roof of the house.

I have a water heater near my shop and i commonly worry about the saw dust. Before i started working i  used 8 mil plastic to separate the utility room off from the shop, and have had no issues.

[conundrum]

We do have them in AZ but they are usually used to cool the water so it's not scalding hot (grin). We also have remote start on our cars but it's used to crank up the A/C for a few minutes so you don't burn yourself getting in the car.

I don't think OSHA would approve of a gas flame in the shop but I've never heard of any issues with it.

[Autorotate]

I have a hot water heater in my shop that's used to heat it using in floor heating. I built a closet around it that also houses  my air

compressor. also it sits on a stand that raises it off the ground about 18 in. so the flame is not so close to the floor where the heavy fumes hang out at. I think according to code any hot water heater in a garage has to be above a certain height for this reason.

[ChrisG-Canada]

If you upgrade the water heater to either a high efficiency tank model or to a tankless version I think it SHOULD draw it's combustion air from outdoor.  For these types of units, the combustion should be totally sealed and won't interact with the shop air at all.  

The only concern at that point might be any heat radiated off the unit - not sure if that could get hot enough to affect any dust and/or fumes.

You could also relocate the heater (may be easier with a tankless model because they take up a LOT less space) to some location inside the house - would free up extra space in the shop!

[collinp2]

I have a gas water heater in the garage and do my finishing in there.  The gas company did an inspection on our fireplace because we smelled strong fumes last winter.  He said the smell was some of the solvent fumes from the garage burning in the air.  He went in the garage and checked furnace and water heater.  He observed the drying finishes and specifically said I am not in danger of blowing up my house.  I was using arm-r-seal that day.  He said the concentration would have to be extremely potent for it to combust in the air like that, and that I had nothing to worry about.  It gave him no pause and he wasn't the least bit concerned about the finishes.