Fixtures on horizontal branch

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Chucky_ott

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This will work, right? My main concern is the vent for the tub and toilet. I think using the 2" wet vent for the lavatory is acceptable ? If not, I can probably put in a 3x3x2" santee anywhere on the 3" pipe and have a dedicated vent. Maximum horizontal run on those bathroom pipes would be 40".

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wwhitney

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Ontario rules may differ, but in the US, horizontal wet venting is limited to bathroom fixtures. So the order of connection on the 3" horizontal line going downstream would have to be

Cleanout
Lav/Tub/WC in any order except lav last
Kitchen Sink

where the lav and the kitchen sink need dry vents, and lav wet vents the Tub and WC.

Cheers, Wayne
 

Chucky_ott

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Moving the kitchen sink drain downstream of the bathroom group might be possible but certainly more difficult. Instead of the wet vent, would a santee and dry vent work?
 

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wwhitney

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The general rule is that each fixture needs to be vented before (dry vent) or as (wet vent) its drain joins another drain. When the kitchen sink is part of the other drain that the fixture drain joins, horizontal wet venting is not a possibility (under US rules). So then only way the kitchen sink could be the upstream most fixture would be if the tub and WC are individually dry vented before joining the 3" horizontal drain.

Cheers, Wayne
 

Jeff H Young

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farthest downstream fitting on drawing a 3x3x2 santee on back , I don't see as changing anything. many codes it wouldn't be legal to have a santee on back for any reason, in the USA. no idea on code in Canada
 

wwhitney

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However, it is possible that the Ontario Plumbing Code allows the kitchen sink to be at the upstream end and drain through the wet vent. I'm not very familiar with that plumbing code, so you may need to get a local opinion. But if this is your plumbing code:

http://www.buildingcode.online/section7.html

Then Section 7.5.2.1(f) has the requirement that "the total hydraulic load on the wet vent does not exceed the limits stated in Table 7.5.8.1. when separately vented branches or fixture drains in the same storey, having a total hydraulic load not greater than two fixture units, are connected to a wet vent or a wet vented water closet trap arm,"

So that seems to allow arbitrary separately vented fixtures to drain through the wet vented section, up to 2 fixture units. [Unlike in the US, where only bathroom fixtures can drain through a horizontal wet vent.]

http://www.buildingcode.online/1076.html

And Table 7.4.9.3 Line 23 says that a kitchen sink is 1.5 fixture units.

http://www.buildingcode.online/1063.html

Thus if I haven't missed anything, the kitchen sink is not a problem for your code. But there's a significant chance I have missed something, not being familiar with Ontario code.

Then for the US codes, having the dry vented lav as the last of 3 bathroom fixtures wouldn't be a valid wet vent, it would need to be first or second. But I will study the above a little more to see what the Ontario code has to say.

Cheers, Wayne
 

wwhitney

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Ah, that didn't take long. 7.5.2.1(d) says "the water closets are installed downstream of all other fixtures." So you need to swap the order of the lav and the WC joining the 3" horizontal drain.

Cheers, Wayne
 

Jeff H Young

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Good info Wayne, I hope OP is positive of the jurisdiction and governing codes. other than his tag saying , Ontario that's kinda like a state and could have city codes? or something like counties within provinces ? Chuckey might want to do some checking or just go for it and plumb with what he thinks is workable.
Sure a lot of work especially not knowing precisely who has jurisdiction . he should verify
 

Chucky_ott

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Thanks all for the information.

This is for a 3-season cottage in the boonies. Although I live in Ontario, the cottage is in Quebec.

When I bought the cottage in 2018, there was only the vent at the kitchen sink and everything was working fine. The 3" horizontal drain goes straight to a septic tank and i'm guessing the bathroom is "vented" that way

Two years ago, I added an AAV for the lavatory in the bathroom.

The cottage was built in the 1950's and the electrical panel is in the bathroom, just above the tub. No shower of course.

I'm moving the bathroom a few feet so that the electrical panel is in its own room (with the required clearances).

The 3" drain is in a crawl space, with barely enough room for me to crawl in. I think the only way to swap the toilet and lavatory drains would be to actually swap the toilet and lavatory.

Anyways, I'll look up the actual codes and do the best I can.
 

wwhitney

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Are the joists perpendicular to the 3" line? If so, then you could run the WC drain between the joists over the 3" line, drop it down below the joists alongside the 3" line on the side opposite the lav, and then parallel the two 3" lines until after the lav comes in.

Cheers, Wayne
 

Chucky_ott

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Yes I had thought of that but the joists are 6" deep. Not sure if the toilet flange, elbow and required slope will require more than 5-1/2" depth. Could do something similar for the lav though.
 

wwhitney

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Could do something similar for the lav though.
Yes, that would be enough and is a better idea:

Bring the WC down below joists parallel to and on the near side of the main 3" horizontal.
Let the lav pass over the WC, then connect it to the main 3" horizontal line, wet venting the tub.
Now connect the WC to the main 3" horizontal line, wet venting the WC and complying with 7.5.2.1(d).

That 7.5.2.1(d) clause is if I use a wet vent. I'll see if I can avoid using that.
To avoid a wet vent, you'd need to individually vent the tub and the WC, each before they join the common line.

Cheers, Wayne
 

Chucky_ott

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How about this? The lavatory drain would actually not need to cross over or under the toilet drain. I'll just run it behind it, under the stud wall.
 

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wwhitney

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So, every (external) trap needs to be vented before the trap arm falls more than one trap diameter (but the trap arm has to fall at least 1/4" per foot). That has several implications for your last drawing:

- You must have a dry vent (through the roof or AAV) at the kitchen sink and at the lav.
- The optional vent you show between the kitchen sink and tub is not useful
- The tub trap arm can't drop down like that to connect to the 3" horizontal line. It has to connect with a horizontal wye for the wet venting. So the 3" line can't be directly underneath the tub trap.
- The optional vent shown in pen isn't useful.

BTW, the restriction on trap arm fall doesn't apply to the WC, as it intentionally siphons its integral trap and then refills it from the tank.

Cheers, Wayne
 

Chucky_ott

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All the wye's in the drawing are horizontal so the tub trap is in the same plane as the 3" drain. I knew after I drew it that it was not clear.

The dry vents for the two sinks I have (shown as dotted lines). If I forgo the two optional vents that don't really have a purpose, I should be good to go?
 

Jeff H Young

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I think your system going to work ok .but we try to give info that is quality legal installation. I think the dry vents arent helping nor hurting dont know that 7.5.2.1 d (ontario code) matters in quebec perhaps same code perhaps not
 

Chucky_ott

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dont know that 7.5.2.1 d (ontario code) matters in quebec perhaps same code perhaps not

Both Ontario and Quebec adopt the National Building Code with some variances/amendments. Quebec appears to follow it more closely. Not sure about local variances at the municipal level.

https://nrc.canada.ca/en/certificat...odes-canada/model-code-adoption-across-canada

https://www.rbq.gouv.qc.ca/en/laws-...and-safety-code/construction-code.html#c20061

The good part is that the latest 2015 codes are available for free:
https://nrc.canada.ca/en/certificat...blications/national-plumbing-code-canada-2015

I'll double-check what the NPC says.
 
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