Plumbing

[craignlisa]

Morning All,

My customer purchased a shower head (12" diameter) and I want to know if we can mount this to the ceiling. I am renovating the bathroom and the ceiling and walls are open, so access to route new plumbing isn't a problem. It doesn't make sense to install a rain-maker head like this one on the wall, having it on the ceiling would be more efficient and give more of a shower effect, but is it to code?

I would like to install the vent for my newly re-located sink in the joists. I have re-located the bathroom sink on the other side of the 9' room. Passing the drain pipe isn't a problem, but the vent is. I would like to go up at the sink location and pass through the ceiling joists to meet up with the old vent location. The problem is that the joists, being spaced 12", are going to make it impossible to pass 9' of rigid abs 1-1/2" dia. tubing thru them. I can see 2 ways of doing this. 1 is to cut 12" long sections of abs, inserting them thru the joists, then re-joining them with glued unions. Is this to code? Keep in mind this is only a vent. The other idea is: Does flexible tuping exist for venting purposes? If it does, is it to code? Flexible tubing would make my life easier but I don't want to do anything that makes this an unprofessional job. By the way, moving the vent stack on the roof is out of the question since this is a quadraplex and that would entail removing walls, etc... in the apartment upstairs.

Thanks,

Craig

[LazyPup]

There are no specific code regulations concerning the height or location of the shower head except a shower head may not be positioned in such a manner as to spray directly towards the shower door.

In order to install the shower head on the ceiling in the manner you describe would only require extending the shower riser tube up to the ceiling, then across to the final location.

At the point of termination you are required to support the shower riser pipe by securing it to the framing. For copper piping this is most easily done by installing a "Drop Ear" elbow on the end of the shower riser. The drop ear elbow is a 90 deg. Elbow that has a solder sweat fitting on the input end, and 1/2"NPT threads on the output end to permit screwing the shower arm directly in. The elbow also has to ear like projections on either side that have a hole through them to permit securing the elbow to the wood framing with a couple screws.

The method of establishing your vent would be determined by what code is in effect in your jurisdiction.

The Uniform Plumbing Code does not permit any horizontal vents. Any transistion from vertical must be a minimum of 45deg and ALL VENTS must terminate through the roof.

The International Residential code is a bit more liberal when it comes to venting. The IRC will permit flat horizontal vents (must be pitched 1/4"/ft upward toward the point of termination.)

Although I personally highly discourage the practice, the IRC will also permit terminating a vent in the attic space, but keep in mind that sewer gasses are heavier than air gasses therefore if you terminate in the attic space it is highly probable that the sewer gasses would then find their way back down into the living space causing severe odor and potential health problems. Terminating a vent in the attic space also results in an excessive amount of moisture buildup in the attic space which could ultimately damage insulation or cause a mold problem.

If you are under the IRC there is another alternative, although I hate to use them. The IRC permits an unlimited use of "air inlet valves" (studor vents) providing the structure has a minimum of one main vent that runs from the house drain through the roof undiminished in size.

Air inlet valves must be located in an accessible position and must be installed a minimum of 4" above the pipe they serve. They are often installed in the lavatory enclosure.

The UPC only allows a maximum of one air inlet valve per structure, and then only with the written approval of the local code inspection authority. (In most instances they will only permit them to create a drain for a kitchen island sink)

Although it would not afford much of a gain in this instance, once an auxillary vent is 6" above the highest flood level rim of the fixtures it serves it may be reduced to 1/2 the diameter of the line it serves, but in no case may it be less than 1 1/4". Reducing your line from 1-1/2 to 1-1/4" would not be much of an advantage.

There are no minimum restrictions on the number of joints you may have, so your idea to drop the 1 ft. section through the header would be fine.

Keep in mind that the code prohibits directly gluing disimilar plastics together so if you have ABS piping now, you will be required to use ABS pipe and fittings to make your vent.

When purchasing the glue and primer make sure they are labelled as approved for ABS.

[craignlisa]

Thanks Lpup!

Nice'n'quick.

Ok for the shower head.

I'll have to run my "vent-joining" pipe horizontally (I'll use the 1/4" per foot)and I've converted all the galvanised steel piping to abs, so I'll be fine when it comes to gluing.

At our home centre I purchased an automatic vent. Is this the studor vent you are writing about? I did speak to a plumber on the application and he said we are allowed by code to install these in the home.

Why do you not like the prospect of installing such a valve?

Anything I should be wary of?

Craig

[LazyPup]

In the jurisdiction where I originally took my training we were under the Uniform Plumbing Code. The Uniform Plumbing code only allows a maximum of one air inlet valve per structure, and then only with the expressed written approval of the code enforcement authority. In most cases the code enforcement officials will only allow air inlet valves for venting a kitchen island sink where it is impossible to run a vertical vent, and you might know that in the jurisdiction where I worked the code enforcement official simply did not authorize them. Consequently we had to learn to install island vents or create other forms of real vents rather than air inlet valves.

While air inlet valves are a lot simpler to install and often can save considerable time, they do require periodic inspection to insure they are working correctly. That may prove to be okay in an apartment structure or commercial building where they have a trained maintenace force in atendance, but when installing the plumbing systems in a residential structure we must always keep in mind that most homeowners have little to no knowledge of technical plumbing, therefore we should strive to make the system as foolproof as possible. Often in new construction, especially when working for a general contractor building turn key homes the plumber never has an opportunity to discuss the system with the prospective home owner so there is no way we can insure air inlet valves would receive the required attention, therefore I personally refrain from using them as much as possible.

Given that you are contemplating installing this device in your own home, we can then assume that you will be aware of its location and the necessity to periodically check it, so you should not have a problem.

There are a couple code requirements you should be aware of. I have prepared the following illustration to show proper layout of an air admitance valve.

[craignlisa]

Judging from your sketch, There is no vent pipe at all.

I am going to install the vent pipe as mentioned. Is the use of an air inlet valve redundant in my case?

And what's the point of sloping a vent (in my case the horizontal vent)?
The original vanity sink configuration had the vent horizontal for 3' then tee'd off to go up to vent thru the roof and go down to meet the bath water drain and vent that too. If a vent is to allow air to compensate for the water draining so that no vacuum builds up, then horizontal or vertical wouldn't make a diff, right?

Craig

[LazyPup]

The illustration shows the method of using an air inlet valve when the length of the waste arm exceeds the maximum limits, which would then require an auxillary vent and no vent presently exists.

In your case you are planning to run a vertical vent, which definitely would be the preferred method. I only offered the information on the Air Inlet valve to show an option if you did not want to run the vent as you describe.


Under the International Residential Code whenever it is necessary to create a horizontal vent it is vital to properly pitch the vent 1/4" per Ft. downward toward the drain. If the vent line was not pitched there is the risk that condensate moisture would form in the vent line and lay at a low point that could obstruct the vent. (The Uniform Plumbing Code prohibits flat horizontal venting, under the UPC the minimum angle for an offset is 45 deg.)

Providing the lenght of the waste arm does not exceed the specified legths it may serve as a combined waste and vent.

The attached illustration shows the method of computing the maximum length of the waste arm under the International Residential Code. The Uniform Plumbing Code derates the lenghts about 40%.

International Residential Code waste arm lenghts:
1 1/4" 5'
1 1/2" 6'
2" 8'
3" 12'
4" or larger 16'

Uniform Plumbing Code:
1 1/4" 2' 6"
1 1/2" 3' 6"
2" 5'
3" 6'
4" or larger 10'

[craignlisa]

Hey LP

I can't believe that I'm gonna need a 3" dia. pipe to drain a sink only because we moved it across the bathroom 8 feet!!

Because I don't want to go thru the bathroom floor then connect with the main drain/waste pipes (3"), I'd have to build a soffit to conceal all this downstairs and lose precious ceiling height. I was going to pass the drain within the wall the sink is standing against horizontally 5'(1/4"/ft pitch included), then pass thru my bath deck turning left 90 deg (it's oversized) then pass down thru the floor there (it's next to the wall structure) and then reconnect to where it originally passed downstairs along the wall. This adds up to 12' total of pipe. So according to your diagram, I have to increase the drain to 3", right?
Does the vent starting at my sink need to increase in dia. too?

If I went to 2" diameter for the drain on this sink, given the above mentioned lengths, would it really be a problem or can I get away with it?

Craig (desperate)

[craignlisa]

Lazy Pup!

Before you comment on my question, look at the diagram I made.

It illustrates the path I need to take before I pass thru the floor. The drain on the sink is made for a 1-1/2" drain tube. If I increase the tube including the "P" trap to 2", pass thru my 2 x 4 wall studs as the 2", then when I enter the bath deck I increase to 3" and pass thru the floor along the back wall and reconnect to the original 1-1/2" branch on the main waste downstairs- will this work?

Craig

[LazyPup]

When sizing pipe we begin by listing the fixtures and their required trap size and Drainage Fixture Units (DFU)

Lavatory 1 1/4 trap 1 DFU
Tub 1 1/2 trap 2DFU
Total load 3 DFU's

The trap may be one nominal trade size larger than the tailpiece, therefore you may use an 1 1/2 trap with a 1 1/4 x 1 1/2 bushing to connect the tailpiece to the trap.

1 1/2 pipe is rated to carry a maximum of 3 DFU's therefore you can run it all with 1 1/2 pipe.

The maximum distance an 1 1/2 pipe may run from the vent is 6'.

The overall run from the vertical waste stack where your are going through the floor to the lavitory measured along the top of the pipe exceeds the 6' limit, therefore this line will require an auxillary vent.

The auxillary vent may be located at any point from directly behind the lavatory at the end of the run to 6' downstream from the lavatory trap.

To create the auxillary vent you may run a vertical vent up through the ceiling into the attic space or you may install an air inlet valve within the 6' limitation.

[craignlisa]

A picture is worth...

Thanks sooooooooo much Lazy Pup. I think I'm gonna sleep better now.

Keep in mind that in their original configuration the tub drained into its own branch on the main stack. It vents thru the same vertical pipe thru the ceiling as the sink but does not share the same 1-1/2 drain pipe with the sink. So I guess I'm doubly ok (is that a sentence?) to run the pipe the way I plannned!

It'll be a pedestal sink, so I'll just "hide" the auto vent behind it-no big deal.

Thanks again for all your help,

Sincerely,

Craig