Thread: IRC M1801.11

IRC
"M1801.11 Multiple-appliance venting systems. Two or more listed and labeled appliances connected to a common natural draft venting system shall comply with the following requirements:

1. Appliances that are connected to common venting system shall be located on the same floor of the dwelling."

From that information, if I come across a remodeled three story house that has a water heater and a standard furnace on ever floor going to the same B-vent (that was just installed), this code is saying that it should not be done.

There is an exception that goes with this code but I don't see that relating to my question.

Am I reading this correctly?

Originally Posted by Kevin Luce

IRC
"M1801.11 Multiple-appliance venting systems. Two or more listed and labeled appliances connected to a common natural draft venting system shall comply with the following requirements:

1. Appliances that are connected to common venting system shall be located on the same floor of the dwelling."

From that information, if I come across a remodeled three story house that has a water heater and a standard furnace on ever floor going to the same B-vent (that was just installed), this code is saying that it should not be done.

There is an exception that goes with this code but I don't see that relating to my question.

Am I reading this correctly?

Kevin,

I can read [ a little ]

Plain language , I'm getting 6 appliances on 3 floors.

Above states appliances connected to common vent shall be on the same floor.

6 appliances 3 floors, So not on the same floor, not allowed on the same venting .

The buyers agent (honest guy) had two heating companies check out this installation and both are saying it's fine. This by itself doesn't bother me since anyone (including my wife) can become a heating technician today. Most of the heating guys around here only go to classes that are offered by the furnace manufacturer. But still, I remember having to call this out when I worked in a heating & cooling company doing work for low income properties for the city of Gary.

The buyers agent is just having a hard time with this since the seller says it's fine, two heating guys say it's fine, but I reported it's not. In most cases, I wouldn't care as long as the heating companies would put it in writing/takes the liability, but this one bothers me for some reason.

Call your local gas company and see what they say. They pretty much control stuff like that around here, when they want to, by red tagging anything they don't like.

Just remember, it's not necessarily OK just because it's there. Some city or gas company person may have just not noticed.

Bring it to their attention and see if they approve it.

In the form of:

IRC says this.
I found this.
What do you say?

Let's think about it logically and what the code it trying to prevent.

If you have multiple appliances venting into the same vent and they are on the same level, then logically the vent/flue should draft properly if they are all attached properly to the flue.

If we add some appliances below or above and connect them to the same flue then we have added additional draft or pressure to the flue. This could keep other appliances that might be above from venting properly.

This might not be the proper technical analogy but it is logical!!

I have to agree with Scott's point on this.
Also, exactly how big is this flue? With 6 appliances it better be pretty damn big. 300-400,000 BTU total input for the units. You might be able to also write it up on that basis.
A question to bring up to your client might also be,' what is he/she planning on doing with those standard furnaces'. With the price of gas leaving some old 60-70% AFUE furnace in place doesn't usually make tenants want to stay more than one winter.

I brought up the code as a secondary comment. I focused on the drafting concerns.

When I have the time, I'm also going to see if I can find something about the locations of the vents. I know that the small vent pipe (normally a water heater) needs to be installed higher than the larger vent pipe (normally the furnace). In this situation, from basement to second floor, they have furnace then water heater connecting into the B-vent. So technically, the two out of the three water heaters are installed below the larger vent pipes.

All it comes down to is draft.

Call your local gas company and see what they say.

Impossible to talk to anymore. Even the city inspectors have given up on them.

I believe you problem is spelled out in the 2006 Uniform Mechanical Code 802..6.4 Vents serving equipment on more than one floor. I think multiple vents is addressed in the 2006 IRC under 2428? (I'm away from my office currently)

Originally Posted by Kevin Luce

The buyers agent (honest guy)

??? Don't think I've seen those words together in a long time.

Originally Posted by K Robertson

??? Don't think I've seen those words together in a long time.

There are six Realtors I know that I truly feel they are there for their client and not the check and actually know what they are doing. Out of 5,000 Realors in the State of Indiana, that's not bad.

Appendix B of the IRC addresses multi-floor venting (which refers back to the Fuel Gas section).

Scratch the question. This is a three family dwelling unit which the IRC does not apply. Don't know why, but it is not allowed for a two family unit dwelling but it is allowed for a three family unit dwelling.

Originally Posted by Kevin Luce

Scratch the question. This is a three family dwelling unit which the IRC does not apply.

Kevin,

Define "three family dwelling unit".

Is it like a duplex but only three units wide instead of two?

If so, then it is a Townhouse, and Townhouses are under the IRC.

This gets back to that "condo" thread where I tried to explain and clarify what type of building was what and which code they were under, no one wanted to complete that thread and arrive at the answer.

As you can see, the answer matters - a lot.

Define "three family dwelling unit".

Three story house on which each floor was converted into apartments. What would you call this?

This gets back to that "condo" thread where I tried to explain and clarify what type of building was what and which code they were under, no one wanted to complete that thread and arrive at the answer.

Never seen that thread.

So are you saying that the cover needs to be changed which currently reads "INTERNATIONAL RESIDENTIAL CODE FOR ONE-AND TWO-FAMILY DWELLINGS"?

Originally Posted by Kevin Luce

Three story house on which each floor was converted into apartments. What would you call this?

That would be under the IBC, IPC, IMC, IFGC, NEC, etc., as that is no longer a single dwelling unit nor is it separate dwelling units from the ground up.

"Condos" and "apartments" are treated the same in the building code.

So are you saying that the cover needs to be changed which currently reads "INTERNATIONAL RESIDENTIAL CODE FOR ONE-AND TWO-FAMILY DWELLINGS"?

The *cover* may say that, but Section 101, Title, Scope and Purpose, say different.

(underlining is mine)

R101.2 Scope.

The provisions of the International Residential Code for One- and Two-family Dwellings shall apply to the construction, alteration, movement, enlargement, replacement, repair, equipment, use and occupancy, location, removal and demolition of detached one- and two-family dwellings and townhouses not more than three stories above-grade in height with a separate means of egress and their accessory structures.

Not that it matters for you looked at.