Installing PEX Piping in Hospitality and Multifamily Projects

Due to its durability and labor savings, PEX pipe is gaining popularity for plumbing and mechanical-piping applications in hotels and high rises

A PEX installation at the Radisson Blu Hotel – Mall of America in Bloomington, Minnesota.

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As some of the most profitable types of commercial real estate for investors, construction is booming in the hospitality and multifamily markets. And with tighter budgets, constrained construction schedules and a shrinking skilled-labor pool, the commercial building industry is seeing the need for innovative, reliable products that meet these demanding needs now, while also offering strong performance decades into the future.

This is exactly why the industry is seeing a shift from metals to PEX for plumbing and mechanical applications — especially in hospitality and multifamily projects. These types of structures are ideal for PEX, a flexible, durable polymer piping product that has been used since the 1970s in radiant heating applications and since the mid-1990s in plumbing applications.

Hospitality and multifamily applications

PEX has become a game-changer because of its versatility in various applications in the hospitality and multifamily arena. Here are the key areas where PEX can be ideal.


PEX is available in sizes up to 3 inches for domestic water risers as well as mechanical piping risers. It is important to have the PEX manufacturer’s design team perform a proper design to ensure the pipe will meet the necessary requirements of the system and also provide long-term performance.

In addition, be sure to support the pipe in accordance with local code and manufacturer’s recommendations. Like metallic piping systems, PEX also requires fire-penetration sealants. There are various products approved for use with PEX, including intumescent caulks, wrap strips, pass-through devices, collars and cast-in-place sleeves. First check with the manufacturer to confirm compatibility with PEX before installing.

Main piping

PEX piping up to 3 inches is a great alternative to traditional metallic systems for horizontal main piping in low-rise to high-rise commercial structures. Along with its ability to resist pitting, scaling and corrosion, the ASTM F1960 expansion fitting system can provide labor savings compared with copper sweat, steel groove or welding.

To simplify support of the PEX piping system, some manufacturers offer a steel support channel that allows for extended support spacing. Some PEX manufacturers also may have specific requirements for clamps and fixed points to help reduce linear expansion and contraction of the pipe. In addition, note that the fire-penetration information above also applies to PEX in main piping.

In-suite piping

Due to its flexibility, PEX is superior for in-suite applications where smaller-diameter pipe can easily bend with each change in piping direction. In fact, PEX-a pipe (the type with the most crosslinking, making it more flexible and durable) offers such a tight bend radius (6x the pipe outside diameter), it practically eliminates the need for elbows in most in-suite applications. There are also PEX bend supports available to help keep the pipe in place when making a tight bend.

For design options, designers can incorporate PEX into trunk and branch, home-run and structured layouts (also referred to as Logic). Logic is a design layout that maximizes the flexibility of PEX along with multiport tees (essentially a long tee with multiple ports) to minimize connections behind the wall. The Logic design features a main line going to a multiport tee with distribution lines going out from the tee. These individual lines extending from the single multiport tee provide water to all fixtures in a single or adjacent grouping.

This style of design and installation vastly reduces the necessary piping, as compared with a home-run system; and it significantly decreases the number of fittings, as compared with a trunk-and-branch system. For example, in a typical multifamily structure, using a Logic design reduces the number of fittings by up to 70% when compared with trunk and branch; it reduces piping footage by 40%, compared with a home-run system.

Below grade or in the slab

Because PEX piping is available in long, continuous lengths, it is ideal for running below grade or in a slab without fittings. (Always follow local codes, as some jurisdictions require additional sleeving and protection.) Some manufacturers offer a presleeved PEX option with red and blue color-coded HDPE sleeving to distinguish between hot and cold domestic waterlines.

Regarding fittings in the slab, the ASTM F1960 fitting connection system is approved for direct burial. Note that brass fittings must be wrapped with an approved material before burial; however, engineered polymer (EP) fittings are approved for direct burial without an overwrap. Be sure to check with local codes and manufacturer requirements before installation.


To really save install time and money, some PEX manufacturers offer a preinsulated piping option with insulation thicknesses up to 2 inches to comply with local and national energy codes, including ASHRAE 90.1. This solution eliminates the two-step process of insulation after pipe installation. Manufacturers offer piping in sizes from 1/2-inch to 2 inches for both domestic water and mechanical piping applications.

To learn more about PEX piping systems or to find a PEX manufacturer in your area, visit or

About the Author

Kim Bliss is the content development manager at Uponor. She can be reached at


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