Plumbing is an essential part of sustainability building practices. According to the National Association of Home Builders, sustainable building practices seek to address “a wide range of issues affecting all consumers: rising energy costs, the need to improve air quality, ensure clean water and minimize water usage.”

That’s why it’s not surprising that more builders, engineers and plumbers are considering sustainability when selecting building materials. Here are the factors to consider when evaluating plumbing system material sustainability as well as some third-party tools you can use in your evaluations. 

FACTORS AFFECTING PLUMBING MATERIAL SUSTAINABILITY

The sustainability of a particular plumbing material, whether CPVC, copper or PEX, is influenced by its embodied energy, longevity and recyclability.

• Embodied Energy: This has become a key sustainability measure for builders and engineers seeking to select materials that minimize greenhouse gas emissions in their manufacture and transportation. Plastic plumbing materials will generally have a lower embodied energy than copper, and CPVC has a lower embodied energy than other plastic plumbing materials. According to data in the National Institute of Standards and Technology Building for Environmental and Economic Sustainability database, over the life of a plumbing system in a small house, the operation of a CPVC plumbing system emits nearly 1 ton less carbon into the atmosphere than a PEX plumbing system. That’s the equivalent of 105 gallons of gasoline.
• Longevity: The longer a product can perform in its intended environment, the less material is ultimately required to support the application. Plumbing materials that are vulnerable to degradation or corrosion from chlorine and other common water treatment chemicals can suffer leaks due to incompatibility with local water conditions that shorten their life. Choosing plumbing materials that are immune to degradation from chlorinated drinking water increases the likelihood that the system will achieve a long life and not need premature replacement. CPVC is the only plumbing material that is immune to chlorinated drinking water.
• Recyclability: Like most metals, copper piping is easily recycled. CPVC can also be recycled at proper centers. PEX is not commercially recyclable and must be landfilled.

DESIGN DECISIONS THAT IMPACT PLUMBING SYSTEM SUSTAINABILITY

Design decisions and material selection can reduce water usage, particularly in multistory buildings.

• Hot water recirculating systems: The International Energy Code requires these systems for buildings three stories or higher because they can reduce the amount of water that is flushed from pipes in hot waterlines. PEX manufacturers and some building codes limit water velocity in recirculating systems to 2 feet per second to protect the material from accelerated chlorine degradation. That can impact flow rates across the system and may require upsizing the piping to compensate for the reduced velocities, negating the water-saving benefits of the recirculating system. Using a material immune to degradation and corrosion from chlorinated drinking water allows velocities of 8-10 feet per second, eliminating the need for upsizing and allowing the full water-saving benefits of the system to be realized. 
• Manifold and mini-manifold systems: Remote or mini-manifolds can be an effective code-compliant workaround to a full hot water recirculating system and can also achieve water savings in smaller buildings not subject to the code requirement. But too often mini-manifolds get executed in a way that negates their benefits and increases project costs. This occurs when the mini manifold is located too far from the fixtures it supports, requiring long branch lines that add to material costs without reducing water waste. Design manifold systems that actively minimize the length of branch lines to help ensure the desired sustainability benefits. Home-run style systems are never environmentally friendly alternatives, as they can increase material use by a factor of 10 or more while also increasing water waste.

TOOLS FOR EVALUATING PLUMBING SYSTEM SUSTAINABILITY

There are multiple tools and resources that can be used to streamline the process of selecting the most sustainable plumbing materials:

• Life cycle assessments: LCAs can be a valuable resource in selecting the most sustainable material. The LCA provides an objective, third-party quantitative analysis of a system’s cradle-to-grave environmental impact, including raw materials, manufacturing, transportation and end-of-life. In addition, products that have an LCA contribute to LEED credits. Ask the material manufacturer if an LCA is available for their system. 
• Certifications: Programs such as the Home Innovation Labs National Green Building Standard provide certifications that can be helpful in quickly identifying products that have been independently verified to improve environmental impact measures and support project certification under the ICC-700 National Green Building Standard. Currently, FlowGuard Gold CPVC is the only NGBS-certified residential plumbing system. 
• NIST BEES: Finally, the BEES software provided by NIST puts a powerful tool for selecting cost-effective, environmentally preferable building products at your fingertips. You can use it to do a direct comparison of the sustainability attributes of different materials.  

CHOOSING SUSTAINABILITY

While sustainability is becoming more important to today’s home buyers, it must be balanced against other factors such as performance and reliability. 

Fortunately, when it comes to plumbing systems, choosing sustainability doesn’t require compromises in other areas. The most sustainable plumbing system also delivers ease of installation, proven reliability in all water conditions and excellent performance in areas like water pressure and water quality. 

Considering all that, there’s no reason not to choose sustainability for your next project.  

Jonathan Simon is the North American residential plumbing manager for Lubrizol Advanced Materials Inc., the parent company for FlowGuard Gold Pipe and Fittings.