Overcoming Barriers to Innovation: PPI, PPFA, Home Innovation Labs Release New PEX Design Guide

If you’re looking for a water supply piping system that doesn’t corrode or develop pinhole leaks, is chlorine-resistant, scale-resistant, and has fewer fittings, connections, and elbows than rigid plastic and metallic pipe, then you might want to explore the use of cross-linked polyethylene (PEX) for your next water supply piping installation.

PEX is a high-temperature, flexible plastic (polymer) pipe. The cross-linking raises the thermal stability of the material under load, therefore, the resistance to environmental stress cracking, creep, and slow crack growth are greatly improved over polyethylene. PEX pipe is approved for potable hot- and cold-water plumbing systems and hot-water (hydronic) heating systems in all model plumbing and mechanical codes across the United States and Canada. PEX piping systems are durable, provide security for safe drinking water, and use reliable connections and fittings. In addition to domestic water supply systems, PEX tubing can be used for floor or wall radiant heating, and snow and ice melting systems in sidewalks and driveways. PEX tubing is lightweight and flexible and can easily be bent around corners and obstacles, and through floor systems. It can also withstand operating temperatures of up to 200° F (93° C). Sizes of PEX tubing range from 3/8-inch to over 2 inches.

While PEX has been available in for use in residential construction in this country since 1984, and had a history of 30+ years of successful use in Europe prior to that, it is only recently beginning to make significant market penetration and still faces a variety of barriers to more widespread use. As part of ongoing efforts to overcome barriers to innovation like this in residential construction, the Plastics Pipe Institute (PPI), Plastic Pipe and Fittings Association (PPFA), and Home Innovation Research Labs released a comprehensive PEX Design Guide in 2008 – having step-by-step guidance on how to use a new technology is often one of the biggest challenges to overcome.

In light of changes in building codes and standards in the five years since the original document was released, as well as technology developments in the fittings used with PEX systems and new design considerations for these systems, PPI, PPFA, and Home Innovation have just released the second edition of the Guide. This latest edition includes many updates to reflect the increased usage of PEX systems in a variety of residential applications like water reuse and retrofit applications. New information has been added to almost every chapter including:

• Standards updates (Chapter 3)
• Updates to all applicable national plumbing, mechanical, and building codes including new green construction codes  (Chapter 4)
• Updates to fitting systems (Chapter 5)
• New design information on fixture flow rates and water hammer (Chapter 8)

In addition to the many updates and continued participation by industry associations and PEX product manufacturers, additional third-party certification bodies, such as the ICC Evaluation Service (ICC-ES), also participated in the creation of this edition. This new level of cooperation makes the Guide more comprehensive, easier to use, and provides more value to installers and inspectors alike.

This Design Guide provides the information and resources necessary to design and install PEX water supply systems in residential buildings, introduces new/prospective users to the technology, and enables current users to optimize their PEX plumbing and fire sprinkler systems and minimize system costs. It includes comprehensive design concepts and installation guidelines to increase the acceptance and proper usage by home builders, designers, and trade contractors. In addition, it will allow code inspectors and homeowners to become familiar with the applications, performance characteristics, and benefits of PEX water supply systems.

If you’re new to PEX and want to find out more, or have been using it for some time and are interested in ways to optimize your designs, download the 2013 edition from the Home Innovation Research Labs website.

ABOUT: Home Innovation Research Labs, located in Upper Marlboro, Md., is a full-service research, testing, and consulting firm determined to improve the quality, durability, affordability, and environmental performance of single- and multifamily homes and home building products – in short, we aim to perfect the home. Founded in 1964 as a subsidiary of the National Association of Home Builders (NAHB), our team has been integral in solving many of our client’s most difficult product and technology issues, and helping to introduce some of the most groundbreaking innovations in construction. Through an interdisciplinary research approach – including market research, building science analysis, laboratory testing, and standards development – we help to find a home for innovation in the construction industry.

NOTE TO EDITORS ON STYLE USAGE: To identify this company and its work correctly, first reference should be "Home Innovation Research Labs." In subsequent mentions, “Home Innovation” should be used; we are not identified by an acronym. Prior to February 12, 2013, the company was known as the NAHB Research Center.