Opening in the hot water heater closet ceiling

[MaMa Mount]

Should there be a opening in the ceiling of a hot water heater closet that can be seen in the picture below. Does it need to be screened as most I see? I know it is for combustion air but not sure it should be opened as such directly to the attic.

I am still in the learning curve.

Thanks Dudes and Dudette's.

Mama

[A.D. Miller]

MM: The opening is required and should not be screened. Another combustion air source must also be provided, preferably in the closet ceiling with a duct that runs to down within one foot of the closet floor.

The openings in the ceiling must terminate above the level of the insulation.

IRC 2407 contains most of what you need.

The Type B vent in the picture does not have sufficient clearance to the ceiling joist.

AND, before someone else does it, I might as well say that it is, of course, not a "hot water heater", but just a "water heater". (Everybody does it.):rolleyes:

[Ron Bibler]

No. any Big rat can get down in that area.

Needs a screen over it.

Looks like you got a roof leak:eek:

Best

Ron

[Ted Menelly]

No. any Big rat can get down in that area.

Needs a screen over it.

Looks like you got a roof leak:eek:

Best

Ron

You don't put hot water in it first???????

Secondly. I know you are not suppose to screen them but I would not have one wide open to my attic with out a screen. Even with the door sealed we are talking insects, possible rodents and such into the home. If above the insulation (not even but well enough above) I don't see the reason (other than a book) not to screen it.

[A.D. Miller]

No. any Big rat can get down in that area.

Needs a screen over it.

Looks like you got a roof leak:eek:

Best

Ron

Ron: No, no screen:


G2407.11 (304.11) Combustion air ducts. Combustion air
ducts shall comply with all of the following:
1. Ducts shall be constructed of galvanized steel complying
with Chapter 16 or of a material having equivalent corrosion
resistance, strength and rigidity.

Exception: Within dwellings units, unobstructed
stud and joist spaces shall not be prohibited from conveying
combustion air, provided that not more than
one required fireblock is removed.
2. Ducts shall terminate in an unobstructed space allowing
free movement of combustion air to the appliances.
3. Ducts shall serve a single enclosure.
4. Ducts shall not serve both upper and lower combustion
air openings where both such openings are used. The
separation between ducts serving upper and lower combustion
air openings shall be maintained to the source of
combustion air.
5. Ducts shall not be screened where terminating in an attic
space.
6. Horizontal upper combustion air ducts shall not slope
downward toward the source of combustion air.
7. The remaining space surrounding a chimney liner, gas
vent, special gas vent or plastic piping installed within a
masonry, metal or factory-built chimney shall not be
used to supply combustion air.

Exception: Direct-vent gas-fired appliances
designed for installation in a solid fuel-burning fireplace
where installed in accordance with the manufacturer’s
instructions.

:rolleyes:

[MaMa Mount]

Most of the moisture stains on the ceilings above the water heaters I think actually comes from condensation collecting on the hot flue pipe in the cold attic and then drips off the flue onto the ceiling. What do you think?

[MaMa Mount]

Aaron, is that opening in that ceiling actually considered a duct though.

[Ron Bibler]

I don't give a ^%*& what that book says. I known what you say and you are correct as to the book. but try and explain that to a mother when a big rat gets in that house and into her kids bedroom:eek:

Under a pest control program to control pest that would be the first thing to do...put a screen on it.

If it was my report I would say screen it.

Best

Ron

[Billy Stephens]

The Type B vent in the picture does not have sufficient clearance to the ceiling joist.


.
Ditto for the ( low voltage? ) wire as it is considered a combustible as well.
.

[Markus Keller]

Screening? What are you guys talking about? Seriously, I have no idea.
As far as around here, open hole like that not allowed depending on flue type and occupancy. Which generally means NO. Comes under insufficient fire separation.

[Jerry Peck]

Aaron, is that opening in that ceiling actually considered a duct though.

Yes, it 'ducts' the air through the insulation and ceiling. :)

That is an arguable (meaning debatable) call.

The code calls for "M1703.2 Two openings or ducts. Outside combustion air shall be supplied through openings or ducts", then, as Aaron posted"
From the 2006 IRC. (underlining is mine)

- G2407.11 (304.11) Combustion air ducts. Combustion air ducts shall comply with all of the following:
- - 1. Ducts shall be constructed of galvanized steel complying with Chapter 16 or of a material having equivalent corrosion resistance, strength and rigidity.

Now, wood, has (for the purposes of that duct) equivalent corrosion resistance, strength and rigidity.

Let's change this around a bit. That duct extends from the ceiling up to past the insulation, but let's just say that it was an "opening" (a hole cut through the ceiling).

Would that 'shall not be screened still apply even though it is not a 'duct'?

Yes. Because that says (much too much to post here) that there are various methods, including the "Two-permanent-openings method" and the One-permanent-opening method", note that the word "duct" is not used here, this is describing "the opening" inside "the duct". The code further complicates matters (interchanging the two words 'openings' and ducts') as in this example: "Where communicating with the outdoors through horizontal ducts, each opening ... " Huh? Yes, the code interchangeably mixes those two words.

Let's go back to "why" no screen is allowed: That is for combustion air, what happens if it becomes blocked (by or for ANY reason)? Where does the combustion air come from? From inside the house where the occupants of the house are - and that's not real good.

It is much more preferable to have *whatever* FALL THROUGH that "opening" than be allowed to stay up on any screen, blocking the opening.

[Jerry Peck]

Screening? What are you guys talking about? Seriously, I have no idea.
As far as around here, open hole like that not allowed depending on flue type and occupancy. Which generally means NO. Comes under insufficient fire separation.

Markus,

I've been on that losing side of that argument so often that I know just what you are talking about ... did I say "on that losing side of that argument"? Thought so. ;)

Show me where in the code you are talking about, referencing dwelling units which fall under the purview of the IRC.

[Jim Luttrall]

I know we have been down this road before but my memory fails me... Why is there no mention of the single opening method in M1700 but is there with required calculations and diagrams in M2400?

[Ron Bibler]

OK. so let say we install a cover that provides for all combustion air needs and in no be blocked (by or for ANY reason)? yet a Rat can not get into the room. Its not a screen and it provides for combustion air?

Best

Ron

[Jerry Peck]

OK. so let say we install a cover that provides for all combustion air needs and in no be blocked (by or for ANY reason)? yet a Rat can not get into the room. Its not a screen and it provides for combustion air?

Best

Ron

Describe one.

[Jerry Peck]

I know we have been down this road before but my memory fails me... Why is there no mention of the single opening method in M1700 but is there with required calculations and diagrams in M2400?

Because the mechanical code provides suitable methods for combustion air under the mechanical section for all fuels ... but if you really want to get into "combustion air" for fuel gas ... you can get more detail in the Fuel Gas code section.

(If I followed your question correctly.)

[A.D. Miller]

Most of the moisture stains on the ceilings above the water heaters I think actually comes from condensation collecting on the hot flue pipe in the cold attic and then drips off the flue onto the ceiling. What do you think?

MM: These stains are usually associated with a lack of proper flashing installation where the vent penetrates the roofing surface. In the "all roofs leak" category, this is at the top of the list for vulnerable areas.


Aaron, is that opening in that ceiling actually considered a duct though.

MM: As JP has said, yes it is a duct. Think of it this way: a duct (a pipe, tube or channel that conveys a substance - Webster's) is simply an medium through which you move air in this case. Like in an air conditioning system, you are moving air from one opening in the duct at the air handler to another in the supply register. For combustion air purposes you are merely allowing the air to move through the ducts by currents induced by the burning of fuels.


I don't give a ^%*& what that book says. I known what you say and you are correct as to the book. but try and explain that to a mother when a big rat gets in that house and into her kids bedroom:eek:

Under a pest control program to control pest that would be the first thing to do...put a screen on it.

If it was my report I would say screen it.

Best

Ron

Ron: Of course, you can write your reports any way that pleases you. But, for actual client education as well as for your own defense in litigation, I would try to stick with the actual facts as described in the law which the code comprises. The reason we have building codes is to prevent a "roll your own" atmosphere in the construction inspection profession.

As for your clients' rodent pets, pest exclusion begins at the outside of the structure and not in the closet ceilings. If, as a PCO, you have allowed the rats in the attic, you are simply not doing your job.

Besides, the water heater cannot legally be located in the kids' bedroom.

:D Aaron

[Jim Luttrall]

Because the mechanical code provides suitable methods for combustion air under the mechanical section for all fuels ... but if you really want to get into "combustion air" for fuel gas ... you can get more detail in the Fuel Gas code section.

(If I followed your question correctly.)

Thanks, It was late (for my brain at least) and I always forget about those northern things like fuel oil. We only use propane, natural gas, and electricity around here.

[Jerry Peck]

things like fuel oil.

And ... wood, coal, pellets, etc. :)