The above is a question very commonly asked. While it may seem like a simple question, how to define the strength of PVC pipe is far from straightforward. The term "strength" can mean a number of things, all of which cannot be covered in one blog post. The three types of strength measurements I will go into in this post are collapse pressure, burst pressure, and tensile strength. These are three of the most common ways to measure the strength of any type of pipe, so I will outline how different types and sizes of PVC compare in terms of those measurements. Included is a helpful PVC pipe strength chart for each, so you will know exactly how strong your PVC is.
Tensile Strength
Tensile strength is, to be put into simple terms, the maximum amount of weight that can be placed on something before it breaks or loses its original shape. PVC pipe tensile strength can be measured by hanging weight from the pipe until it bends or cracks.
As you can see from the chart to the right, tensile strength of PVC pipe increases as the size of the pipe increases. 8" PVC pipe of either schedule is extremely strong for how inexpensive it is. The smaller sizes are exponentially weaker, but can still hold a great deal of weight if they must.
Burst Pressure
Burst pressure is basically what it sounds like: the amount of internal pressure pipe can take before it fails. It is a measurement that should be taken into consideration anytime you are pumping any kind of fluid through a piping system. PVC pipe often gets a bad rap because it cannot handle as much pressure as various types of metal pipe. However, smaller sizes of PVC pipe, especially schedule 80, can handle plenty of pressure for most home and business uses.
Unlike tensile strength, burst pressure decreases as pipe size increases. The smaller pipes are far less likely to fail due to internal pressure problems. If you look closely you will notice that 2.5" pipe has a slightly higher burst pressure rating than 2", oddly.
Collapse Pressure
Collapse pressure (or PVC pipe crush strength) is the amount of outside pressure a pipe can take before it starts collapsing inwards. This is an important measurement when burying pipe for subterranean applications. To test this type of strength, you can place weight on a pipe until it starts buckling.
As with burst pressure, the amount of collapse pressure PVC pipe can withstand decreases as size increases. Schedule 80, as is the case in all three strength measurements, is much stronger than schedule 40 PVC. It can withstand a substantial amount of exterior pressure.
There are other ways of measuring the strength of PVC pipe strength, but those would require much longer explanations. These three types of measurements answer most questions our customers have concerning the strength and structural integrity of PVC pipe. In conclusion, PVC is not as strong as metal, but is often the perfect choice, especially when you are on a budget!
