UPC 1002.3 Change of Direction in a Trap Arm

[wwhitney]

Hello,

What's the reason for this limitation of 90 degrees of change of direction without a cleanout? Why the stricter standard than the 135 degree requirement of 707.4?

Thanks,
Wayne

 

[James Henry]

If you read further it states that for 3" and larger the max is 135 degrees which implies that the smaller the trap arm the hard it is for the snake to run through it.

 

[Sponsor]

 

[Reach4]

If you put a trap adapter at the wall, you can remove the slip drain stuff and clean through there.

 

[hj]

If the plumber knows what he is doing, there is no need for more than a 90 degree turn for a small trap size.

 

[wwhitney]

I agree with all the responses so far, but none of them really explain the 1002.3 requirement compared to 707.4

Per 707.4 exception (4), I could have a 1-1/2" horizontal vanity drain line, and after the vent is taken off with an upright wye, I could have as many bends as I like above the floor level without any clean out. Yet before that vent takeoff, 1002.3 limits me to a single 90 degree bend unless I want to add a clean out.

Why? Is a clog before the vent take-off somehow much worse than a clog after the vent take-off?

Thanks,
Wayne

 

[James Henry]

I think the confusion is stemming from the terminology. A " trap arm " is technically the arm that extends from the fixture trap to the drain outlet coming out of the wall. When I did plumbing in Phoenix, AZ. 15 years ago the drain outlet between the trap arm connection to the nearest vent was called the "Dirty arm ", That was where you have the limitations on length, after the dirty arm it was called the " drain", think of the many pictures of plumbing under peoples sinks that go around in circles then maybe it makes sense to have a clean out. Look up the definition of a " trap arm" in the plumbing code definition section. That's why they have a "definitions" section so the rules are clear. I could be wrong it won't be the first time and it won't be the last.

 

[wwhitney]

From Chapter 2:

Trap Arm. That portion of a fixture drain between a trap and the vent.

Wayne

 

[James Henry]

I agree with all the responses so far, but none of them really explain the 1002.3 requirement compared to 707.4

Per 707.4 exception (4), I could have a 1-1/2" horizontal vanity drain line, and after the vent is taken off with an upright wye, I could have as many bends as I like above the floor level without any clean out. Yet before that vent takeoff, 1002.3 limits me to a single 90 degree bend unless I want to add a clean out.

Why? Is a clog before the vent take-off somehow much worse than a clog after the vent take-off?

Thanks,
Wayne

Looks like you answered your own question.

 

[wwhitney]

If so, then how is a clog before the vent take-off worse than a clog after the vent take-off?

Thanks,
Wayne

 

[James Henry]

If so, then how is a clog before the vent take-off worse than a clog after the vent take-off?

Thanks,
Wayne[/QUOT

At this point I am just guessing. perhaps a clog develops easier if their is no vent behind the flow and the added bends in the drain also contribute to easier clogging. I can tell you one thing for sure, plumbing engineers aren't the only ones that write the plumbing code, contractors and product distributors lobby the code authority to add their pet projects in the code, perhaps some contractors lobbied them for that code rule to make it easier for them to snake the drains. the fact that 3" and larger is not restricted to 90 degrees makes sense on both fronts, easier snaking and plenty of air flow for drainage, so what's the answer.