PVC (polyvinyl chloride) is a durable, inexpensive material that can be used for several different types of projects, but it isn’t necessarily the “be all end all” when it comes to HVAC applications. It will work great in some instances, while it won’t be appropriate in others. Here are some commonly asked questions regarding PVC and how it can best be utilized for HVAC-related work.
What are some of the best uses for PVC?
PVC can be used for some heating and cooling projects but not for others. It is a sturdy material relatively easy to install, and can be used in walls, floors, ceilings and several other indoor environments. It should work well, for example, if a builder wants to install heating and cooling grills in the floor of a home, or if a house doesn’t have enough space to install metal ductwork.
How efficient is PVC at transporting hot and cold air?
PVC is far superior than metal when it comes to insulation. Metal tends to disperse air, making a heating and cooling system have to work much harder in order to make an indoor environment comfortable. PVC is very good for larger buildings where conditioned air has to travel longer distances through ductwork.
How long does PVC typically last?
There are areas in Europe where PVC has been in continuous use since the 1930s. Most studies indicate that PVC is durable enough to last 100 years or even longer. In many instances, PVC will last longer than the buildings in which they are installed.
Is PVC recyclable?
Yes, but since it lasts so long there is rarely a need to dig up PVC and replace it. Scraps of PVC left over after cutting to size, however, are often recycled to make new pipes.
What is one of PVC’s chief limitations when it comes to HVAC applications?
It does not handle substantial heat very well. The maximum temperature at which PVC can function properly is 140 degrees Fahrenheit. As a result, if you are planning certain types of heating-related projects you will probably need to consider an alternative material.
Is PVC expensive?
While PVC is typically more expensive to manufactures than other commonly used materials, the difference in cost is relatively small. While it could be somewhat costly to install PVC in large-scale projects, the higher price should not be much of a concern for smaller projects. However, PVC could provide substantial long-term savings for even larger installations because it helps increase heating and cooling equipment efficiency.
Can PVC be mixed with other materials when installing ductwork?
No. When you use PVC in ductwork, you need to keep in mind that you will not be able to mix it with any metal parts. PVC and metal come in different sizes and shapes, so they are not easily interchangeable. This could become a major issue that makes any future upgrades or maintenance extremely complex.
How will PVC behave should a fire occur?
PVC is combustible, but once the source of the flame is removed it will not continue to burn. However, like many other materials, PVC can emit potentially fatal carbon monoxide if exposed to flame. The risk is low, however, because PVC is typically installed behind materials that are noncombustible.
I see a line in some of the PVC that I’m preparing to install. Does that mean it’s defective?
Probably not. While PVC is brittle and can crack easily if mishandled, the lines you see are very likely due to part of the manufacturing process. These lines form when melted plastic flows through one side of the pipe-mold cavity and then fills into the opposite side. As long as you cannot open the pipe by pulling on it, there is no crack.
How is PVC affected by continued exposure to the sun?
There are stabilizers built into PVC pipes that help them withstand ultraviolet light. If used in an outdoor HVAC installation, it may become discolored but it will still be able to perform at optimum level. Use a water-based paint (not oil based) that is compatible with PVC in order to protect PVC from prolonged UV exposure and keep discoloration from occurring.
How would I fix a PVC pipe leak at a weld joint?
If possible, you’ll need to remove the leaking joint and start over, because that likely means the joint was not properly welded. This could have happened for one of several reasons, such as a foreign material being trapped in the joint, a damaged component or the joint may not have been bottomed completely. You may be able to use a plastic fillet hot-air weld on the exterior of the pipe, but that will only be a temporary fix. In addition, it will only be appropriate for an extremely minor leak.
Amanda Hill is the Content and Creative Manager for PVC Fittings Online, based out of Rock Hill, South Carolina. PVC Fittings Online is a supplier of PVC pipe, Schedule 80 PVC Fittings and accessories for commercial contractors all across the United States