UPC and IRC fuel gas. Propane in small cabin

Users who are viewing this thread

viper1

New Member
Messages
23
Reaction score
2
Points
3
Location
S KS
I used to work for a plumbing company and have done plenty, but crossing a bridge here trying to get a small cabin built in a picky county. We have adopted 2018 IRC but plumbing was specifically deleted and reverts to UPC code.

My plan... Cabin will use a direct vent 11k btu wall furnace, 40gal/32k btu tank water heater, and a single burner cooktop. I am running into a very tight situation with required combustion air per code.

My volume of this small 12x15x10 vaulted space will be 1935cf. But I guess "interior" space might be 1665cf. So when we look at available max btu natural vent capacity, that is either 38.7kbtu or 33.3kbtu input. I am trying to find the lowest btu input tank i can find and so far a 30gal/29kbtu. The single burner cook top is about 6500 btu. So that is 35.5kbtu. I can get a double burner unit and possible 'blank off' the second burner but.....we are getting into dumb land here.

When I look at the real mathematical side of this, I know exactly how much combustion air is needed but this just becomes a matter of getting it signed off. I will not have electric in this space so direct vent or tankless is out of the question to get it signed off, though that is probably what will happen down the road.

Questions.
1. Want to install a single 20lb (bbq cyl) directly on side of structure. Per IFC, this is not an issue, but I am not sure about the rubber hose/regulator for code? I can see them not liking that but I could also use a stainless flex line? Thoughts on mounts for this? They will want something firmly affixed.

2. I will run steel gas pipe in structure and not sure if that is required to be grounded these days? I would sure think so! Which code governs this? NEC? Because there is no other electric, a ground rod will have to be driven.

3. The water heater discussed will have to be in the bathroom as those appliances are not accepted in 'habitable rooms'. I am curious if UPC governs any applicable vent grills in the walls to provide makeup air?

4. The cooktop will technically be in a habitable room because the bedroom and kitchen are all the same space. Remember we are talking small. Do you guys see issues? The plans review guy has zero issue but he is also not the one that inspects these and I don't want post build drama.
 

viper1

New Member
Messages
23
Reaction score
2
Points
3
Location
S KS
Just bumping to see if any plumbers can help? Gotta figure this out soon.
 

Terry

The Plumbing Wizard
Staff member
Messages
29,942
Reaction score
3,459
Points
113
Location
Bothell, Washington
Website
terrylove.com
A gas water heater can't be in a bedroom or a bathroom. And of course it will need ventilation low and high.

I did install a direct vent wall heater in the basement of a home I owned. Pretty nice when the power went out.
 

viper1

New Member
Messages
23
Reaction score
2
Points
3
Location
S KS
Thanks Terry. Not to argue but I am curious where in code it says that a WH cannot be in a bathroom? I did talk to a plumber friend that indicated it was fine, and I believe under UPC it indicates a gas appliance cannot be in a habitable room unless direct vented. However, under IRC it specifically notes that a bathroom is not considered a habitable space.?
 

wwhitney

In the Trades
Messages
6,532
Reaction score
1,822
Points
113
Location
Berkeley, CA
Have you considered putting the water heater in a lean-to or a closet that is sealed from the interior and gets combustion air from the exterior?

Cheers, Wayne
 

Tuttles Revenge

In the Trades
Messages
4,132
Reaction score
1,410
Points
113
2015 UPC: 504.1 Location. Water heater installation in bedrooms and bathrooms shall comply with one of the following: (1) Fuel-burning water heaters may be installed in a closet located in the bedroom or bathroom provided the closet is equipped with a listed, gasketed door assembly and a listed self-closing device. The self-closing door assembly shall meet the requirements of Section 505.1.1. The door assembly shall be installed with a threshold and bottom door seal and shall meet the requirements of Section 505.1.2. All combustion air for such installations shall be obtained from the outdoors in accordance with the International Mechanical Code. The closet shall be for the exclusive use of the water heater.
 
Last edited:

viper1

New Member
Messages
23
Reaction score
2
Points
3
Location
S KS
I have but those "natural direct vent" heaters are very rare, expensive, and hard to find. My intent was to use a common tank that could be easily replaced. Outdoor install is not an option due to freeze. What is odd is I have seen countless bathrooms with a tank in them. Not saying they meet code but I am sure trying to find that. An inspector's "opinion" should not override actual code so I am just trying to sort code at the moment.
 

wwhitney

In the Trades
Messages
6,532
Reaction score
1,822
Points
113
Location
Berkeley, CA
I have but those "natural direct vent" heaters are very rare, expensive, and hard to find.
But what about using a regular natural draft water heater in an exterior access-only closet? It would be sealed and (somewhat) insulated from the interior, with an an insulated ventilated door to allow combustion air to come from the outside. The closet would get some passive heat gain through the (somewhat) insulated boundaries with the rest of the cabin, and some heat loss through the air vents in the door.

If the operation of the water heater itself doesn't provide enough heating of the closet to prevent freezing of the water pipes in the closet, then the idea would be to reduce the insulation somewhat between the closet and the living space to provide additional passive heat gain.

Cheers, Wayne
 

viper1

New Member
Messages
23
Reaction score
2
Points
3
Location
S KS
Alright, well that code seems to be rather explicit and though we could maybe consider all the provisions of a sealed space, I think natural direct vent will just be required.

So....... It looks like AO smith, Bradford, and Rheem have direct vent models. Any other bargain tanks we can source here? Really prefer a 30gal here but won't fight it too much if price is near the same.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks