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International Plumbing Code as alternative code in Washington

By Chris van Daalen and IPC WA Website
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International Plumbing Code as alternative code in Washington
Image by International Codes Council
Plumbing Systems
Alternative Standards
Proposed legislation
Washington State
Washington State
WA Representative Vincent Buys
State Building Codes Council
Northwest EcoBuilding Guild
Jan 19, 2017
Hearing in WA Leg. Cmte on Local Government, 8:00 am 1/25/17


In January 2017, Representative Vincent Buys (R-Lynden-LD42) introduced H.B. 1435, an act which would recognize the International Plumbing Code as an alternative building code to the Uniform Plumbing Code which comprises Washington State Plumbing Code. This Bill is endorsed by the Northwest EcoBuilding Guild as part of their 2017-2018 "Make it Easier to Build Green" Advocacy campaign.

Origin and purpose

This proposal arose from the frustration of builders and building code officials at being constrained to the traditional design, technology and materials prescribed by the Uniform Plumbing Code (UPC), as amended by Washington State.  The International Plumbing Code (IPC) they argue, is based on modern science and technology rather than "centuries old" plumbing methods, it provides both a prescriptive path and performance path, and explicit recognition for innovative designs and technology not allowed under the UPC.  The Bill would recognized the IPC as an alternative code, not in addition to the UPC, meaning it would not create new mandatory requirements, but only provide a transition path and an optional compliance path for projects wanting to use modern or innovative methods.

Advocacy Initiative Title Goal or Purpose of Advocacy
House Bill 1435: Adoption of International Plumbing Code as a Recognized Alternate "AN ACT Relating to adoption of the International Plumbing Code as an alternative recognized building code; amending RCW 19.27.031 and 19.27.170; and creating a new section."

Activity and Impact

From the IPC-WA Website:

"The International Plumbing Code was developed to ensure a cost effective, safe and fully functional installation based on scientific principles.

"Because it is based upon scientific principles rather than century old methodologies, the IPC provides for a more cost effective plumbing installation. It eliminates the need for most venting systems thereby reducing labor and material costs and as an added bonus actually saves energy through the elimination of most roof vent penetrations."

Scope and Application

The IPC is a member of and fully integrated with the International Codes family.  The majority of the country uses the IPC. The federal government uses the IPC.  The City of Bellingham, WA has adopted the IPC as an alternative code for its own application, which is overseen by Jim Tinner, City of Bellingham Building Official.

Additional Resources

IPC for Washington Website "The Truth about Competing Plumbing Codes" Building Operators and Managers (BOMA) Statement of Support for International Plumbing Code

Technical Details

From the IPC-WA Website:

"The IPC recognizes that modern water closets use no more than 1.6 gallons per flush and are incapable of filling a 3″ horizontal drain pipe. Accordingly, the UPC 6′ limitation before the trap arm meets it’s vent is eliminated. Under the IPC there is no limitation. That make plumbing a bathroom on a second floor far easier in most cases.

"The IPC recognizes that air admittance valves (AAV) really work. The UPC does not. In fact you’ll hear all sorts of horror stories about AAV failures but in reality with tens of millions of them installed I’ve never been able to find a single documented case of AAV failure. Even if there were failures, AAV’s are inexpensive and can be replaced in a few minutes.

"Use of AAV’s greatly decreases the cost of drainage systems. Imagine installing a new bathroom in your basement under the UPC. You would have to tear open walls all the way through your attic and then drill a new hole in your roof to get a vent out.

"Under the IPC, you simply put a tee under your sink, with an AAV on top the tee. For water closets or bathtubs you simply run the drain to a wall, install a tee as you would for a conventional vent, install vent pipe at least 4″ above the drain, screw on an AAV and you’re done.

"There is no logical reason not to allow use of the IPC in Washington State.

Economic Impact

Continuing to constrain buildings and code officials to using the UPC, means plumbing a building is more expensive, requires more materials, and prohibits the use of technology and solutions that are less water- and energy-efficient.  It means that high-performance buildings cannot incorporate many optimal plumbing innovations without going through a costly and time-consuming "alternative materials and methods" permitting process outside the normal prescriptive path.  The IPC on the other hand provides specific prescriptive paths for many of the most advanced innovations that can reduce labor and material costs and save energy.

The UPC is written by IAPMO made up of 1/3 plumbers and 1/3 plumbing manufacturers, which gives them a financial interest in maintaining a code that requires more labor and materials.

Future Outlook and Replicability

There will be a Hearing in the House Local Government Committee on later in January.  This will be an opportunity to testify in support of the Bill, so check back for updates.

Project Contacts
Advocate: Chris van Daalen, Principal Investigator Northwest EcoBuilding Guild Code Innovations Database (360) 789-9669 Advocate: Kraig Stevenson, Western Region Government Affairs Manager International Codes Council Approving Official: Jim Tinner, Building Official City of Bellingham
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