The 2015 Uniform Solar Energy and Hydronics Code

Radiant Professionals Alliance active in helping industry understand new code provisions.

The International Association of Plumbing and Mechanical Officials (IAPMO) first developed and published the Uniform Solar Energy Code (USEC) in 1976. The code was developed in response to an interest in residential and commercial solar energy systems. This year, the code became the Uniform Solar Energy and Hydronics Code (USEHC). This code was developed using IAPMO’s American National Standards Institute (ANSI)-accredited open consensus process, and is unique in that it is both a code and a standard.

The 2015 edition includes significant provisions concerning hydronic and geothermal systems. The code was developed to govern the installation and inspection of solar, hydronic, and geothermal energy systems as a means of promoting the public’s health, safety and welfare.

Colin Wunder, veteran contractor and vice president at Energy Dynamics, said that the changes to the code came right in time.

“I believe the solar code came first because of the debacles of the ‘70s when unscrupulous, would-be contractors sold flawed systems,” Wunder explained. “Getting geothermal in the 2015 code was necessary. For once, maybe we can get ahead of the curve by having an enforceable, changeable and upgradable standard. This way, mistakes of the last 40 years won’t get repeated and lessons learned from those mistakes can be propagated.”

Vaughan Woodruff, contractor and owner of Insource Renewables, agreed with Wunder on the timeliness of USEHC.

“Until recently, the solar portion of that code was the only comprehensive set of codes specific to that technology in the U.S. Solar is similar to other hydronic heating systems in some ways, but there are some major differences that can’t be accounted for in a broad code,” Woodruff said. “Having something that creates the specifics for minimum requirements really helps ensure public safety and helps create a strong foundation for a technology.”

Key provisions of the 2015 USEHC include:

  • New Hydronics Chapter.
  • New Geothermal Energy Systems Chapter.
  • New Duct Systems Chapter.
  • New condensates waste and control provisions.
  • New solar thermal provisions.
  • New alternative engineering design provisions.
  • New electrical provisions for the installation of solar photovoltaic systems based on NFPA 70-2014.
  • New provisions for accessibility, attic and underfloor installation, and roof installation of appliances and equipment used in solar energy, hydronic, and geothermal energy systems.

Wunder said that he feels the provisions accurately encapsulate the information that the industry needs, for now.

“I believe they will all be expounded on in future code cycles and there will be more appendices for better explanations. The great thing about the code process in America is if you don’t like something, you can be an instrumental part, as an individual or group, to change it. Code cycles happen on a three-year basis. Get involved,” Wunder said. “My next recommendation to this code will be an illustrated version. That would be great!”

Woodruff emphasized the point of code development involvement among industry professionals.

“As contractors, we’re all really busy. So, sometimes it’s challenging to find the opportunity to participate in the code development process,” Woodruff said. “But, I think most of the code organizations are excited to have experienced contractors take a seat at the table. Just know that you can be active.”

Leg work

The Radiant Professionals Alliance (RPA) got on board as an early supporter of the USEHC and its additions. The RPA has offered voluntary guidelines in the past, but felt there was little information available that was meaningful and useable regarding design criteria and best practices.

The RPA’s involvement in the development of the code helped ensure that state-of-the-art design and construction principles were considered.

“The RPA Codes and Standards Committee held an intense two-day working group session early on in Mokena, Ill.,” said Mark Eatherton, executive director of the RPA. “We came away with a lot of great suggestions from well-known subject matter experts for code change proposals for the 2015 USEHC. Most proposals made it through the consensus process intact, and others may be resubmitted as future proposals to the USEHC.”

Eatherton continued, “It has taken years of diligent effort by the RPA and the industry. When the decision was made to create a hydronics code, the RPA was successful in creating a committee representing all facets of the industry. The RPA Code Committee spent well over a year compiling relevant information, even from foreign countries, and molding it into a working document.”

The results

Today, the USEHC is one of the only model codes that specifically addresses the design and installation of solar, geothermal, hydronic, and radiant heating and cooling systems. The availability of this code means that in jurisdictions where it is adopted a single source for many provisions affecting the installation of these systems will be available.

The code will provide residential and commercial consumers the assurances and protections of a viable, quality installation in an understandable format. It will also serve as verification for the industry’s experienced professionals that when the code is followed their work will exceed minimum expectations.

To increase awareness of and confidence in the code among professionals and end users, ASSE International is developing a “Hydronic System Installer and Hydronic System Designer” national standard and certification program. The goal of this effort is for Authorities Having Jurisdiction (AHJs) to recognize this certification and require it as minimum criteria to allow industry professionals to perform work in their jurisdiction. The program is expected to be released in 2016.

In addition, RPA is developing “Instructive Training” and “Best Practices” manuals. The manuals will be used to ensure that industry professionals have been provided with the tools necessary to ensure proper and appropriate applications of mechanical systems. The materials will take readers through the steps necessary to ensure that the delivery method correlates with the energy source.

Moving forward

RPA has formulated a specific marketing plan for its stakeholders to explain the benefits of USEHC to each group. The stakeholders that the alliance has identified are: contractors, manufacturers, engineers, architects, enforcement, and end users.

Each stakeholder group will be reached through print media, social media, membership publications, and e-mail. RPA manufacturer members have agreed to publicize the USEHC to customers and other corporate contacts. In addition, education curricula will be developed to ensure understanding of the code provisions.

For contractors, RPA hopes to convey that the provisions of the USEHC will help eliminate confusion and controversy on the part of AHJs by establishing consensus guidelines for the application of radiant and hydronic technologies in the built environment. The alliance and IAPMO have begun teaching and working with code enforcement officials, such as AHJs, to bring their knowledge base of mechanical systems up to speed. Both groups believe that a code is only as good as the enforcement in the field.

“About six years ago we had a very high-profile series of projects in Maine that was run through a state housing agency. There was an evaluation reported in local papers highlighting how poorly the projects were implemented, including blatant code violations that weren’t caught,” Woodruff explained. “Having that blistered all over the front of newspapers reflected poorly on our entire industry. This was an extraordinary case of contractors who didn’t know how to meet minimum requirements. Additionally, we didn’t have a code enforcement structure in place to identify issues.”

Woodruff continued, “That happens in many developing industries. There are so many different ways to skin the cat. Having experts come together to create minimum requirements is supportive of installation professionals because it sets a common set of rules to follow. This is especially useful for new professionals in the industry.”

For manufacturers, engineers, and architects, RPA has found the benefits of USEHC to be the same. All of those parties now have pertinent design and installation topics, previously addressed in multiple codes or regulations, available in one standard. The code is a single-source reference for the installation, use, or maintenance of radiant, hydronic, geothermal and solar systems, which ultimately could lead to increased utilization of such high-efficiency and renewable energy systems.

“It is my hope that contractors will take the minimum code to a new level, changing it to improve it,” Wunder said. “The new code could, or should, raise their level of understanding and professionalism to a level not seen before in these trades.”

For the end users, RPA says that the key benefit is confirmation of a vetted process. The industry can confidently tell an end user that the USEHC has been developed by subject matter experts in accordance with scrutinized system design criteria and accepted construction techniques.

To read the 2105 USEHC online, visit

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