UPC 706.0: That section is about changing the direction of drainage flow
Just in case my fan was wondering where I’ve been, I’m happy to inform you I’ve been given some additional tasks and just haven’t carved out the time required to write a column.
Now, in addition to Green Plumbers Training, I‘m working on the technical side of the Uniform Plumbing- and Uniform Mechanical Codes and getting down to the nuts and bolts of plumbing design and installation and now there is more.
In 2014 I was asked to work on the inclusion of pertinent sections of the UPC into the Indonesian National Standard of “Plumbing System for Building.” I was honored to visit the cities of Jakarta and Bandung, to work with government officials in helping them understand what was meant and required by certain sections of the UPC.
Without spending the whole column on my experiences, I’ll just say it is has always been rewarding, satisfying and educational to work with others who are truly trying to improve the health and safety of the public. I’m pleased to announce that in May IAPMO published the first ever English translation of the Indonesian Plumbing Code [http://goo.gl/lsSf6f]. We believe, when these new requirements, including the very important plumbing fixture reference standards are fully integrated into the construction process, Indonesia will be a healthier nation with a safer potable water supply.
I’ve been one of several IAPMO staff reviewing the 2015 UPC and UMC Study Guides in preparation for publication. We are doing everything we can to make sure the questions and answers are accurate and relevant. If you find a mistake please help us out by letting us know.
There are other ongoing projects, but the reason for this month’s column is I’ve been working on processing code questions for the UPC and UMC Answers and Analysis committees. I am reminded that in helping others find the correct answer or solution to a problem, all of us are better informed. With that goal in mind, I want to begin sharing nuggets of information from the UPC.
1st nugget 706.0 Changes in Direction of Drainage Flow.
706.1 Approved Fittings. Changes in direction of drainage piping shall be made by the appropriate use of approved fittings and shall be of the angles presented by a one-sixteenth bend, one-eighth bend, or one-sixth bend, or other approved fittings of equivalent sweep.
As a novice, on first reading this section, it seems pretty simple, but trust me, this one requirement and the others that follow in section 706 are multifaceted. May I suggest that you look at a DWV installation as a geometric problem waiting for an answer…understanding there may be many solutions. Some will be better than others, always with the goal of using less pipe, fewer fittings and requiring fewer cleanouts. Just remember, you are limited to “the appropriate use of approved fittings” or “equivalent sweep”.
Before we continue in section of 706, I’m going to limit my comments to changes in direction of flow. There is an additional language in 706.2 I hope to cover later but for now I’m just focusing on: H to V, H to H and V to H
706.2 Horizontal to Vertical. Horizontal drainage lines, connecting with a vertical stack, shall enter through 45 degree (0.79 rad) wye branches, 60 degree (1.05 rad) wye branches, combination wye and one-eighth bend branches, sanitary tee or sanitary tapped tee branches, or other approved fittings of equivalent sweep.
Hold your hand out from your body and move it in a horizontal direction — now stop and drop your hand straight down. That is the change in direction of flow this section is talking about, horizontal to vertical or H to V.
The most significant information from this first sentence is the minimum sweep allowed to change direction from horizontal to vertical is equivalent to a sanitary tee. The only approved fitting of equivalent sweep is a regular ¼ bend. You may be tempted to call it a 90° elbow and while that is accepted in the trade, it is not what the manufacturers call it. As such it can lead to confusion, especially since there are at least 4 materials (cast iron, plastic [PVC & ABS], copper and galvanized wrought iron or recessed drainage fitting) where sometimes the names of the fittings are the same and others they are not.
And while we are talking about sweeps, it’s easy to think 0.79 rad is the minimum radius (or sweep) of the fitting. However “rad” is the abbreviation of Radian. Radian is a standard unit of angular measure. Notice it follows the degree information in the section. Now you’re almost ready for Plumbing Jeopardy!
706.3 Horizontal to Horizontal. Horizontal drainage lines connecting with other horizontal drainage lines shall enter through 45 degree (0.79 rad) wye branches, combination wye and one-eighth bend branches, or other approved fittings of equivalent sweep.
Hold your hand out again making the same change of direction as before, except this time go from horizontal to horizontal or H to H. Note also the minimum sweep allowed to change the direction from horizontal to horizontal is a wye or combination, a more gradual sweep or than required in section 706.2. Therefore it will have a larger radius than a regular ¼ bend.
And this is where the trouble can begin……it is just not as bad if you use the name the manufacturers assigned to the fitting. The minimum fitting required to connect two horizontal sections of pipe are, depending on the material:
Cast Iron: Short Sweep, ABS, PVC or Copper DWV: Long Sweep, Recessed Drainage Type: Extra Long Turn. However, and it’s no big surprise, it appears the last fitting it is no longer available.
706.4 Vertical to Horizontal. Vertical drainage lines connecting with horizontal drainage lines shall enter through 45 degree (0.79 rad) wye branches, combination wye and one-eighth bend branches, or other approved fittings of equivalent sweep.
If that sounds familiar it’s probably because it is almost exactly the same as section 706.3 and it uses the same fitting as H to H.
- Section 706.0 addresses three 3 different changes of direction: Horizontal to Vertical, Horizontal to Horizontal and Vertical to Horizontal or H to V, H to H and V to H.
- Whatever the material, a ¼ bend is the minimum fitting required to connect 2 pipes when the change of direction is horizontal to vertical (H to V).
- The next longer radius fitting is required when connecting 2 pipes and the change of direction is Horizontal to Horizontal and Vertical to Horizontal (H to H or V to H).
- If you want to make sure you get the right fitting, call it by the name the manufacturer has assigned to it.
a. There are no DWV fittings called medium sweeps by the manufacturer.
Inspired by a 1993 article by George Kaufman in the Official Magazine I have a chart to help you keep all the above information straight. It’s elsewhere on this page.
You can download a copy here: https://goo.gl/hWKPGk
"This article was originally posted on ww.reevesjournal.com."