Many changes have been proposed to the Uniform Plumbing Code.

A proposed change to the UPC would add a new listing of 1/2 DFU for the fixture unit value for non-water supplied urinals.

The IAPMO code change cycle to develop the 2012 Uniform Plumbing Code is now in full swing. All of the code changes have been submitted and the first meeting of the Plumbing Technical Committee will occur April 26-28 in Milwaukee.

After the past few cycles that have seen an extensive number of changes, everyone expected a light cycle. That is not to be. There are more than 250 proposed changes to the Uniform Plumbing Code.

Green Theme

Going green will be a major theme during this code cycle. As all of you know, IAPMO issued its green plumbing code. Now, the committee that put the green code together is proposing to add many of the green code requirements to the Uniform Plumbing Code. This includes many water conserving requirements.

One proposal would mandate 1.28 gallons per flush or HET water closets. This is a change from the 1.6 gallon-per-flush water closet. Such a change raises all sorts of questions. Unlike the green code, the Uniform Plumbing Code is adopted by many states as the enforceable plumbing code. Water conservation for plumbing fixtures is regulated by the federal government. The federal requirements are listed as being pre-emptive, meaning no state is permitted to change those requirements (up or down).

One of the arguments regarding the water-closet flush volume will be that California has already, by state law, lowered its flush volume, while the opposing view is California’s law doesn’t make it right. Furthermore, the California legislation has yet to be tested in the courts. The discussion on this change should be interesting.

Also included in the water conservation code changes is a proposal to limit the amount of water in a shower to a single showerhead. Currently, the UPC has been interpreted as allowing multiple showerheads in a shower. The change would eliminate multiple showerheads and allow only 2.5 gallons per minute of total water for taking a shower. This change shouldn’t stir much emotion since that is plenty of water for a shower.

With the lowering in the amount of water use, there are a few changes to the sizing of the drainage piping. One change proposes to lower the shower drain size to a minimum of 1 1/2 inches. Currently, the UPC requires a 2-inch minimum shower drain.

Non-Water Supplied Urinals

Another oversight in the UPC is the sizing and fixture unit value for non-water supplied urinals. A change is proposed to add a new listing of ½ DFU for the drainage fixture unit value. While not affecting the fixture drain, this would have a significant impact on the size of the drain when a series of non-water supplied urinals are installed.

Attempts to place the fixture unit value for non-water supplied urinals failed during the last code cycle. There was testimony that if you replace the non-water supplied urinal with a water-supplied urinal, you need the piping in the wall to accommodate that water-supplied urinal. This is someone attempting to predict the future of plumbing and plan for it. Of course, it makes no sense. To try and predict what may happen with a change in fixtures is not the purpose of the code.


ASPE has submitted changes on venting requirements and siphonic roof drainage. One of the changes proposed is to move the circuit venting requirements from Appendix L to Chapter 9. It makes no sense to isolate circuit venting requirements in an engineered design appendix. These requirements belong in the venting chapter of the code.

ASPE has again proposed a change to add air admittance valves to Appendix L as an engineered design. This change is very similar to the change submitted in the last cycle by ASPE. That change was approved through the normal code change process only to be block-voted down at the annual meeting. What those attending the annual meeting failed to understand is that air admittance valves can already be used under the engineered venting design section of the code. However, without guidelines in the code, the authority having jurisdiction has no means of evaluating the proper design and installation.

It will be interesting to see where IAPMO, as an organization, positions itself regarding air admittance valves. For almost 25 years, the sky has been falling when you mention air admittance valves at an IAPMO annual conference. Yet, everyone continues to wait for the day when all air admittance valves fail and make everyone sick.

It is estimated there are more than 10 million air admittance valves installed in the United States alone. You have to wonder how much longer you can stick your head in the sand and say they don’t work.

The siphonic roof drain proposal is a repeat code change from the last cycle. This was also approved through the cycle, only to be voted down at the annual meeting. Siphonic roof drainage has been used more and more by plumbing engineers. The UPC needs to add the requirements so the authority having jurisdiction has the necessary tools for enforcing the requirements. The resulting requirements would reference ASPE 45 for the design of the system.


With the changes to the IRC mandating residential sprinklers in all one- and two-family dwellings and townhouses, there is a change to address multipurpose piping systems. This deals more with backflow protection, or lack thereof. Backflow is not required when the sprinkler pipe and the sprinklers are listed to NSF 61.

IAPMO also developed a supplement on residential sprinklers. The supplement is similar to Section P2904 in the 2009 International Residential Code. Basically, there are requirements for a plumbing-based residential sprinkler system. The concept is to use this document in place of NFPA 13D for a basic system. When there is more complexity to the system, you would have to use NFPA 13D.

If you are in the Milwaukee area at the end of April, stop by the Hilton City Center and see how the code change process works. I’ll be there. I hope to see some of you there, as well.