How would the fixture units be counted in the following situation: a shower room in which there are two shower fixtures and a soaking tub (which drains to the floor), all of which are drained through a single floor drain....Would this be counted as 1 fixture (a shower albeit a big one), or would it be counted as 3 fixtures (tub and 2 showers)? Thanks....
Fixture units question...
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Plumber69
In the Trades
Your confusing fixtures with fixture units
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Ok...let me give a little more background to my question...
I have a wet room, 8' x 11' which will have two showers and a soaking tub (drain onto the floor of the wet room). All of these will drain from the room via a 3" floor drain. To vent this floor drain, I would like to wet vent it through the double vanity drain in the adjacent room. In Wisconsin, apparently I am allowed to wet vent two toilets or two bathtubs in such a manner. I want to know if my floor drain counts as one shower for wet venting or would the two shower heads in addition to the soaking tub put me over the limit....Thanks.
Cacher_Chick
Test, Don't Guess!
To meet WI code for wet venting, each shower is required to have a drain which connects individually to the common horizontal drain, downstream of the vertical lav vent.
The way I see it, it's one big shower since there is only one drain...because there are two shower heads shouldn't mean it needs two drains, should it? I see these multiple head shower and body spray showers- they only have one drain....???
Since this 3" drain is at the end of the drain piping, it seems it would be in essence a 9 foot trap arm (less than the max of 12' for a 3" pipe). Wouldn't the wet vent be located as drawn with the solid line? Doesn't seem right to have the wet vent upstream of the 3" drain connection as drawn with the dotted line as the drain behind the connection would be horizontal and a flat vent in essence.... Which is correct? Thanks for your time...
Since this 3" drain is at the end of the drain piping, it seems it would be in essence a 9 foot trap arm (less than the max of 12' for a 3" pipe). Wouldn't the wet vent be located as drawn with the solid line? Doesn't seem right to have the wet vent upstream of the 3" drain connection as drawn with the dotted line as the drain behind the connection would be horizontal and a flat vent in essence.... Which is correct? Thanks for your time...
Cacher_Chick
Test, Don't Guess!
If were built with a single drain, 3" is not appropriate because the fixture does not flow enough to scour it. It would not be permitted to call it a floor drain when it is actually a fixture drain for the shower. P
The WI code is clear about what is allowed for horizontal and vertical wet vents. If you have not downloaded it yet, it would be a good place to start.
The WI code is clear about what is allowed for horizontal and vertical wet vents. If you have not downloaded it yet, it would be a good place to start.
Maybe here is the answer:
SPS 382.30(3)
What is the dfu value of a garage catch basin?
According to SPS Table 382.30, the drainage fixture unit value of a floor drain is four. Since a garage catch basin is a modified floor drain, the dfu value of a garage catch basin is also four, regardless of the number of fixtures or trenches connected to the basin,
And here:
SPS 382.31(13)(b)
May only one water closet be included in a horizontal wet vent where there are two lavatories and two bathtubs or showers?
Yes. The only limitation of the horizontal wet vent is that more than two
water closets may not be included on the vent
SPS 382.30(3)
What is the dfu value of a garage catch basin?
According to SPS Table 382.30, the drainage fixture unit value of a floor drain is four. Since a garage catch basin is a modified floor drain, the dfu value of a garage catch basin is also four, regardless of the number of fixtures or trenches connected to the basin,
And here:
SPS 382.31(13)(b)
May only one water closet be included in a horizontal wet vent where there are two lavatories and two bathtubs or showers?
Yes. The only limitation of the horizontal wet vent is that more than two
water closets may not be included on the vent
Cacher_Chick
Test, Don't Guess!
I think you are ignoring section of the code that applies directly to your bathroom plan.
(b) Horizontal wet vents. A drain from a lavatory or lavatories which are either provided with individual vents or a common vent may serve as the wet vent for not more than 2 bathtubs or showers and not more than 2 water closets in accordance with subds. 1. to 7. No other fixtures may discharge into or be served by the wet vent.
1. All of the fixtures shall be located in nonpublic bathroom groups.
2. The lavatories and bathtubs or showers shall have a common horizontal drain with the drain for the lavatories serving as a wet vent for the bathtubs or showers.
3. Where 2 bathtubs or showers are served by the same wet vent, their fixture drains shall connect independently to the common horizontal drain downstream of the vertical drain serving the lavatory or lavatories.
4. Where 2 bathtubs or showers and 2 water closets are served by the same wet vent a relief vent shall be provided, unless the wet vented horizontal drain connects to a drain stack with no other drain connections located above the wet-vented horizontal drain. The relief vent shall connect to the horizontal drain at a point downstream of the fixture drains for the water closets and upstream of any other fixture drain connections.
5. One or 2 water closets may connect to the common horiœ zontal drain with the drain from the lavatories and bathtubs or showers also serving as a wet vent for the water closets. Where 2 water closets are served by the same wet vent, their fixture drains shall connect independently to the common horizontal drain at the same point.
6. The wet vent shall be at least 2º in diameter. No more than 4 drainage fixture units may discharge into a 2º diameter wet vent.
7. A branch vent shall connect immediately above the highest fixture drain connection and shall be sized in accordance with sub. (14).
(b) Horizontal wet vents. A drain from a lavatory or lavatories which are either provided with individual vents or a common vent may serve as the wet vent for not more than 2 bathtubs or showers and not more than 2 water closets in accordance with subds. 1. to 7. No other fixtures may discharge into or be served by the wet vent.
1. All of the fixtures shall be located in nonpublic bathroom groups.
2. The lavatories and bathtubs or showers shall have a common horizontal drain with the drain for the lavatories serving as a wet vent for the bathtubs or showers.
3. Where 2 bathtubs or showers are served by the same wet vent, their fixture drains shall connect independently to the common horizontal drain downstream of the vertical drain serving the lavatory or lavatories.
4. Where 2 bathtubs or showers and 2 water closets are served by the same wet vent a relief vent shall be provided, unless the wet vented horizontal drain connects to a drain stack with no other drain connections located above the wet-vented horizontal drain. The relief vent shall connect to the horizontal drain at a point downstream of the fixture drains for the water closets and upstream of any other fixture drain connections.
5. One or 2 water closets may connect to the common horiœ zontal drain with the drain from the lavatories and bathtubs or showers also serving as a wet vent for the water closets. Where 2 water closets are served by the same wet vent, their fixture drains shall connect independently to the common horizontal drain at the same point.
6. The wet vent shall be at least 2º in diameter. No more than 4 drainage fixture units may discharge into a 2º diameter wet vent.
7. A branch vent shall connect immediately above the highest fixture drain connection and shall be sized in accordance with sub. (14).
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Cacher_Chick
Test, Don't Guess!
I can see where you might read it that way, but a plumber or inspector, or anyone that does understand, would not.
If you read the section on vertical wet venting, then it might become more clear.
In the diagram you posted, it is showing a water closet being vented by a lavatory. The water closet is the upstream fixture. You are confusing horizonal wet vent vs. vertical wet vent, and you cannot substitute how the code applies. It might help if you rationalize that the venting starts at the fixture's trap, not at the vent take-off.
If you read the section on vertical wet venting, then it might become more clear.
In the diagram you posted, it is showing a water closet being vented by a lavatory. The water closet is the upstream fixture. You are confusing horizonal wet vent vs. vertical wet vent, and you cannot substitute how the code applies. It might help if you rationalize that the venting starts at the fixture's trap, not at the vent take-off.
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Check.
So are you saying that if a shower stall has multiple shower heads it has to have multiple floor drains? The code says a garage floor drain can service multiple fixtures. I would assume wet room drain would be no different...
There is nothing in the code I can find that limits the water flow into a shower stall. As long as the drain is sized to accommodate the water flow, I see no issue.
The use of 2 lav drains to wet vent according to the code is limited to 4 fixture units. Code says a floor drain is 4 fixture units, regardless of the number of fixtures it serves.
There is nothing in the code I can find that limits the water flow into a shower stall. As long as the drain is sized to accommodate the water flow, I see no issue.
The use of 2 lav drains to wet vent according to the code is limited to 4 fixture units. Code says a floor drain is 4 fixture units, regardless of the number of fixtures it serves.
Cacher_Chick
Test, Don't Guess!
The code is written based on standard fixtures. A standard shower valve does not flow with enough volume to require a drain larger than 1-1/2". WI code is 2" drain for a shower (1-1/2" in Canada).
Where your installation raises concern is that the rules for wet wenting a bath group are very specific. Until you get an inspector to sign off on your plan, you should not expect to be able to deviate from that which is specifically written in the code for wet venting. The devil here is reading the details word for word, and the way you are interpreting the code is not the same way a plumber or inspector is likely to.
Where your installation raises concern is that the rules for wet wenting a bath group are very specific. Until you get an inspector to sign off on your plan, you should not expect to be able to deviate from that which is specifically written in the code for wet venting. The devil here is reading the details word for word, and the way you are interpreting the code is not the same way a plumber or inspector is likely to.
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