Distinct PVC Pipe Types Clarified
Polyvinyl chloride, commonly known as PVC, is one of the most versatile and widely used thermoplastic materials for piping systems. With a variety of types and sizes, PVC offers an economical and durable solution for many residential, commercial, industrial and municipal applications.
We will also compare PVC to other popular piping materials to help you determine when PVC is the right choice for your project.
Types of PVC Pipe
There are several different classifications of PVC pipe, each with their own unique properties and applications. The main types include:
PVC Schedule 40
PVC Schedule 40 is the most common type of PVC pipe used in building construction. It offers a good balance of strength, chemical resistance, and affordability. Schedule 40 is suitable for use in plumbing, drainage, irrigation, electrical conduit and process piping applications.
PVC Schedule 80
As the name implies, PVC Schedule 80 has a thicker wall than Schedule 40, making it stronger and more rigid. It is primarily used for plumbing high-pressure water lines and industrial process lines that require additional strength and durability.
CPVC Pipe
Chlorinated polyvinyl chloride (CPVC) has similar properties to PVC, but can withstand higher temperatures. CPVC is typically used for hot water plumbing lines up to 200degF. It offers better heat resistance than standard PVC.
PVC Drain Waste & Vent Pipe
DWV pipe is a heavier grade PVC designed specifically for underground drain, waste and vent lines. It is thicker than Schedule 40 and can withstand the constant pressure changes associated with drain systems.
Cellular Core PVC Pipe
Cellular core PVC uses a honeycomb design in the middle to provide exceptional rigidity and strength. The cellular core makes the pipe extremely lightweight while maintaining durability. It is commonly used for sewer systems and sewer pump mains.
Ribbed PVC Pipe
Ribbed PVC pipe has ribs protruding along the length of the pipe. The ribs add strength and prevent sagging, making this type well-suited for underground trench applications and low-pressure irrigation systems.
PVC Well Casing
PVC well casing is engineered to withstand the forces found in water well systems. The pipe is thicker and stronger than standard PVC to handle the friction of driving it into the earth and pumping water through it from an aquifer or water table.
PVC Pipe Sizes
PVC pipe is manufactured in both iron pipe size (IPS) and metric diameters. Common sizes include:
Nominal Pipe Size
The nominal pipe size (NPS) is an approximate inside diameter based on older iron pipe designations. For instance, 2" NPS indicates a 2-inch nominal size, even though the actual outside diameter is around 2.375".
Actual Outside Diameter
Since PVC pipe walls are thinner, the actual outside diameter will always be larger than the nominal size. A 2" pipe has an OD of around 2.375 inches.
Inside Diameter
The inside diameter (ID) indicates the size of the opening of the pipe's bore. A 2" Sch 40 PVC pipe has an ID of around 2.067 inches, allowing good flow rates.
Pressure Ratings
PVC pipe pressure ratings indicate the maximum internal pressure it can handle. Sch 40 has higher pressure ratings than Sch 80. Pressure ratings also go up as the pipe size decreases.
PVC Pipe Applications
Thanks to its versatile properties, PVC has a wide range of applications across residential, commercial, industrial and municipal settings.
Plumbing Systems
PVC is approved for DWV systems, water supply lines, and vent stacks in plumbing applications. Sch 40 and Sch 80 are common for supply lines. CPVC can be used for hot water.
Irrigation Systems
PVC piping is ideal for above ground irrigation systems in yards, gardens and agricultural applications due to its durability and low cost.
Electrical Conduit
The non-conductive properties of PVC make it useful as an electrical conduit for protecting and routing electrical wiring. PVC conduit handles moisture well.
Process Piping
PVC is suitable for transporting chemicals, acids, and corrosive fluids in chemical plants, industrial facilities and purification systems.
Drainage Systems
PVC is common for underground drainage pipes and French drains. It is affordable and its chemical resistance prevents corrosion and rust.
PVC Pipe Benefits
There are many benefits that make PVC a top choice for piping applications:
Durability
PVC pipes are highly durable and have a long service life. Properly installed systems can last 50 years or more.
Chemical Resistance
PVC has good chemical resistance and will not corrode when exposed to acids, alkalis and salts. It is suitable for many chemicals.
Cost Effectiveness
PVC is one of the most affordable piping materials. It offers a cost-effective solution for many applications.
Ease of Installation
PVC pipes are lightweight, easy to cut, join together with solvent cement and require no special tools.
Variety of Sizes and Schedules
With options like Sch 40, Sch 80, and cellular core, PVC is available in a range of wall thicknesses for different pressure requirements.
PVC Pipe Limitations
Despite its many benefits, PVC does have some limitations to be aware of:
Not Heat Resistant
PVC pipe can become brittle and fail when exposed to temperatures over 140degF, making it unsuitable for steam or hot water applications.
Not Meant for High Pressure
PVC is only rated for low to moderate pressures. It cannot handle very high-pressure applications over a few hundred PSI.
Requires Glue for Fittings
PVC pipes must be bonded together using solvent cement glue. The joints are permanent and cannot be easily disassembled.
UV Degradation Concerns
When exposed to UV light, PVC can become brittle and crack over time. Painting or shielding is required for outdoor installations.
Cannot Be Used with Some Solvents
PVC piping cannot handle exposure to solvents like acetone. Caution is required when piping industrial chemicals.
PVC vs Other Pipe Materials
How does PVC compare to other popular piping choices like copper, PEX and cast iron?
PVC vs CPVC
CPVC can handle higher temperatures over 200degF but is more expensive. PVC works for many cold and hot water applications.
PVC vs PEX
PEX is flexible but not as rigid and strong as PVC. PEX also has more limited chemical resistance.
PVC vs Copper
Copper has better pressure ratings but is much more expensive and prone to corrosion and freeze damage.
Cast iron is stronger but extremely heavy, difficult to work with, and prone to rust. PVC is lighter, easier to install and maintain.