Pre-sleeved PEX Maximizes Plumbing System Hygiene and Installation Efficiencies

Shorter pipe runs means water spends less time in the optimal temperature range for bacterial growth

Pre-sleeved PEX Maximizes Plumbing System Hygiene and Installation Efficiencies

Interested in Fixtures/Materials?

Get Fixtures/Materials articles, news and videos right in your inbox! Sign up now.

Fixtures/Materials + Get Alerts

Bacteria in domestic water systems has been around since the beginning of plumbing. However, with the COVID-19 pandemic and surge in deaths linked to Legionnaires’ disease, the public health community is bringing plumbing hygiene into even sharper focus.

In fact, cases of Legionella in plumbing systems have skyrocketed in the past decade. Why? Outdated plumbing codes call for pipes that are much larger than they need to be to supply modern, low-flow fixtures. This results in lower water velocity, which makes it easier for bacteria to attach to the inside of pipe walls and begin to grow.

Also, energy codes that require insulation on hot-water lines (which is important for combatting energy loss) help keep domestic water systems in the prime growth temperature range for Legionella bacteria. Temperatures of 120 degrees F and above will kill off the bacteria, while temperatures below the prime growth range (cold-water temperatures) hinder the bacteria from multiplying. 

In short, code requirements keeping our hot-water temperatures at 120 degrees F and below for safety, and then insulating these pipes, are keeping the bacteria in its prime growth temperature range for as long as possible. Of course, water treatment programs incorporate disinfectant strategies to kill the bacteria. However, after the bacteria is killed and the system returns to its normal operating state, the dead bacteria simply become food for the new bacteria colonies that thrive in the normal operating temperatures for hot water.

It is easy to see how all the elements of this perfect storm have come together. As a consequence, public health and hygiene in domestic water systems have become a focus for building owners and professionals in the plumbing and construction industry. There needs to be a solution that not only meets the demanding requirements for commercial domestic water, but that also is cost-effective to meet tight project budgets and efficient to install to meet tight project schedules.

Pre-sleeved solution

For these commercial plumbing applications, professionals are starting to turn to pre-sleeved PEX in the slab. It’s an innovative solution that offers several benefits for the installing contractor, including:

  • Shorter pipe runs, resulting in far less material usage and better pressure to the fixtures.
  • No hangers, resulting in less ladder time, faster installs, and lower materials costs.
  • No insulation required, resulting in easier, more efficient, more cost-effective installs.
  • Long, flexible coils of pipe, resulting in the elimination of pipe fittings in the slab.

Meanwhile, here is where the safety factor comes into play. Because in-slab pre-sleeved PEX systems use shorter runs of pipe embedded in concrete, the water in that pipe spends less time in the optimal bacterial growth zone. Plus, these shorter pipe runs provide better pressure to the fixtures for higher velocity to minimize biofilm attachment and growth, especially compared with metallic piping systems.

PEX vs. metallic pipe

In general, PEX is a superior product compared with metallic piping due to its corrosion- and freeze-resistance, superior sound insulation qualities, smoother surface for reduced pressure loss, and lighter weight for easy maneuverability and greater safety on the job site.

Also, PEX pricing is more stable pricing than copper’s, so it’s easier to bid a job confidently without having to worry about price increases. And because PEX connections do not require any flame, there’s no need for fire-watch requirements on a job site, adding to the cost-effective benefits of the system.

While there’s a perfect storm in domestic water systems for bacterial growth, there’s also a perfect solution. Many pre-sleeved PEX offerings feature color-coded red and blue HDPE corrugated sleeving to easily identify hot and cold water lines. The HDPE sleeve not only protects the pipe in the slab, but also makes it easier to remove, if necessary, without having to break up the slab. Pipe sizes are typically available from 1/2-inch to 1-inch, but can vary by manufacturer.

To learn more about the pre-sleeved PEX offerings in your market, check out your favorite PEX manufacturer’s website. To learn more about PEX in general, visit one of the plastic piping association websites at or

About the Author

Kim Bliss is the technical and marketing content manager at Uponor. She can be reached at


Comments on this site are submitted by users and are not endorsed by nor do they reflect the views or opinions of COLE Publishing, Inc. Comments are moderated before being posted.