When it comes to plumbing systems, proper support for pipes is essential to ensure their longevity and prevent potential failures. Plumbing pipe supports not only keep the pipes in place but also prevent them from sagging, bowing, or breaking due to excessive weight or pressure.
In this article, we cover everything you need to know about plumbing pipe supports, including the reasons why they are necessary, the requirements to prevent potential failures, and intervals of support.
Understanding the importance of proper pipe support can help you avoid costly repairs and ensure the safety and efficiency of your plumbing system.
Two Reasons Why Proper Plumbing Pipe Supports Are Necessary
It Keeps Piping Systems Secure
While it’s easy to believe that DWV (drain, waste and vent) pipe doesn’t weigh much, think again. In particular, cast iron pipe tends to be heavier, especially if a single section of the line is several feet long. Furthermore, drain pipes also carry a great deal of wastewater weight.
Like DWV systems, don’t underestimate the weight of supply-pipe lines filled with water. Also, remember that supply pipes are constantly under pressure to help ensure water flows from our faucets. Force or strength is used to push water through pipes or other pathways and is created by altitude or height.
The bottom line: An improperly supported system could result in pipes crashing through a wall or down from a ceiling – hurting someone or causing damage to the building, or both.
Additionally, if there is a backup in a drainpipe, you may have a three or four-inch diameter line, depending on which part is backed up. Pair that with, say, 20 feet of pipe filled with wastewater, and you’re looking at a lot of weight.
If your piping system wasn’t properly secured or hung, especially in a multi-level building, the backup will have to go somewhere at some point, so the pipe may come apart. That could result in drywall damage or – even more serious – water damage.
Another major consideration is the danger associated with improperly supported gas lines. The last thing you want are sagging gas lines generating extra stress on a connection. If that joint breaks and fails, you will have a natural gas leak that could result in life-threatening explosions.
It Reduces Movement
Using pipe supports effectively will also help reduce noise in DWV systems or “water hammer” in water supply systems. A water hammer is a hydraulic shock in a piping system when water flow stops suddenly. When a valve or faucet is closed, the sudden change in the velocity (speed) of the water flow creates kinetic energy that raises pressure within the pipe. That pressure gain resonates and creates waves inside the piping, resulting in a shuddering sound.
While water hammer is audible, the sound may be deceiving. It’s not easy to pinpoint the exact location of the issue, e.g., the location of, say, a washing machine. The sound may appear to be coming from the valve area, but it could be the result of an unsecured pipe within the wall cavity.
Water hammer can be absorbed by any unsecured lines, resulting in partial-to-extreme movement – creating contact with adjacent surfaces. Pipes should be adequately supported and/or insulated to prevent touching any of the surrounding building materials. Pipe insufficiently secured will move and cause a knocking or vibrating sound when coupled with even the slightest amount of water hammer.
Requirements To Prevent Potential Failures
To ensure the satisfactory operation of a piping system, carefully consider support location and type. Plumbing codes require that all piping and the contents inside be supported in such a way that the pipe maintains alignment and doesn’t sag.
Plumbing codes typically require hangers and strapping materials to be made of an approved material that will not promote galvanic action. Of course, they must also be of sufficient strength to support the weight of the pipes and their contents.
Always attach hangers and anchors to walls in accordance with local plumbing codes. In addition, provide sway bracing at directional changes more than 45 degrees for pipe sizes four inches and larger.
A sway brace is recommended for controlling vibration, absorbing shock loadings, guiding or restraining the movement of pipe resulting from thermal expansion, and – as the name indicates – bracing a pipe line against sway. Use anchors to restrain drainage pipes from axial movement.
Intervals of Support
Support spacing should follow applicable plumbing and building codes. Below, we share the maximum horizontal and vertical spacing for Schedule 40 PVC and ABS, CPVC, copper and PEX, based on the IAPMO Uniform Plumbing Code and the International Plumbing Code.
However, the information below provides general guidelines and serves only as a reference. Engineering specifications for a particular project may require specific installation instructions.
Schedule 40 PVC and ABS: Most plumbing and building codes require support for horizontal Schedule 40 PVC and ABS pipelines every four feet for any pipe diameter, allowing for expansion every 30 feet.
The IAPMO Uniform Plumbing Code (UPC) states that vertical spacing for ABS piping should provide a mid-story guide as well as for expansion every 30 feet. See: Section 313.0 Hangers & Supports, Table 313.3.
The International Plumbing Code (IPC) states maximum vertical spacing of ABS is 10 feet. For sizes two inches and smaller, a guide should be installed midway between the required vertical supports. Such guides will prevent pipe movement in a direction perpendicular to the axis of the pipe. See: Section 308 Piping Support, Table 308.5.
CPVC: Most plumbing and building codes require support for horizontal CPVC pipelines one inch and smaller every 3 feet; for diameters 1-¼ inch and greater every four feet.
The UPC states that vertical spacing for CPVC piping should provide a mid-story guide and for expansion every 30 feet. See: Section 313.0 Hangers & Supports, Table 313.3.
The IPC designates maximum vertical spacing of CPVC is 10 feet. For sizes two inches and smaller, a guide should be installed midway between required vertical supports. Such guides will prevent pipe movement in a direction perpendicular to the axis of the pipe. See: Section 308 Piping Support, Table 308.5.
Copper: Most plumbing and building codes require support for horizontal copper pipelines 1-¼ inch and smaller every 6 feet. The IPC indicates supports every 10 feet for diameters 1-½ inches and greater; the UPC, every 10 feet for diameters 2 inches and greater.
The UPC and IPC both call for vertical spacing not to exceed 10 feet. See: Section 313.0 Hangers & Supports, Table 313.3 (UPC); and Section 308 Piping Support, Table 308.5 (IPC).
PEX: The IPC requires support for horizontal PEX pipelines 1-¼ inch and smaller every 2.67 feet, or 32 inches. The UPC requires the same spacing support for pipelines 1 inch and smaller; and every four feet for 1-1/4 inch and larger diameters.
The IPC states maximum vertical spacing for PEX is 10 feet. For sizes two inches and smaller, a guide should be installed midway between the required vertical supports. Once again, such guides will prevent pipe movement in a direction perpendicular to the axis of the pipe. See: Section 308 Piping Support, Table 308.5.
The UPC states that vertical spacing for PEX piping should provide a mid-story guide and provide for expansion every 30 feet. See: Section 313.0 Hangers & Supports, Table 313.3.
Different Types of Pipe Support Hangers
The appropriate pipe support for a given piping system depends on the pipe material itself.
Water supply pipe is Copper Tube Size, commonly referred to as CTS.
Gas and drain pipes are considered Iron Pipe Size, or IPS.
To break it down, a one-inch piece of copper or CPVC pipe is going to require a different hanger type and size than a comparable piece of gas pipe because of factors like wall thickness, diameter, and load (weight of the piping).
Below, we share some of the many plumbing pipe support hanger options for DWV and Supply line hangers, and how they are best utilized.
Used to secure to or support pipes below the wall, ceiling or floor, DWV hangers include J-Hooks, Hanger Straps, Cable Conduit, Duct Ties, etc.
DWV J-Hooks are used to secure drain piping, allowing for expansion and contraction. They can be used to support DWV piping from joists and rafters. With multiple nail holes for attachment to pipe runs at various angles, its unique diagonal nail holes allow for easy attachment in tight areas.
Metal Hanger Straps are a quick and inexpensive way to hang pipe from joists or rafters.
Interlocking Metal Hanger Straps support copper, CPVC and PEX water supply lines from joists and rafters.
Universal Pipe Hangers are used to suspend pipe from framing. The strap adjusts to accommodate one to six-inch diameter pipe, and the orientation of the strap can be reversed based on installation needs. Straight and angled nail hole patterns accommodate tough installation angles. They meet ASTM requirements and are APMO approved.
Supply Hangers (CTS)
Full Clamps with Nails, designed with a preloaded nail, allow for fast and easy push-on installation for all types of CTS piping.
Insulating Pipe Clamps, for use on plumbing and hydronic systems, are designed to eliminate pipe notching and wrapping when running water lines through framing.
CTS Bell Hangers offer light-duty support standoff of pipe or copper tubing from a wall or object.
CTS J-Hooks, provide a fast, easy and economical way to secure supply-line piping from joists and rafters.
Whether it be securing plumbing or hydronic supply lines or DWV drainage, or supporting your work with brackets and bars, choosing quality pipe supports provides the necessary protection and support against potential failures related to water hammer, weight load, floor and ceiling penetrations, and more.
Sean Comerford is a Technical Applications Manager at Oatey Co. He is a third-generation tradesman with nearly 20 years of plumbing experience, including serving as the lead plumber for commercial/residential new construction, service and fire protection jobs. He holds a State of Ohio Fire Protection License for Sprinkler and Standpipe. He can be reached at firstname.lastname@example.org.