Whether you’re a DIY enthusiast or want to be more informed about your home’s plumbing system, knowing how to identify different PVC pipes and fittings can save you time and prevent costly mistakes. In this guide, we’ll explore various types of PVC pipes and fittings commonly used in residential plumbing. This Old House plumbing and heating expert Richard Trethewey provides a comprehensive overview of PVC pipes and fittings in the video above.
Types of PVC Pipes
PVC pipes are a popular choice for residential plumbing due to their durability, affordability, and ease of installation. Here are the main types of PVC pipes you’ll encounter:
White PVC Pipes
White PVC pipes are the most common type used for drainage systems in the United States. They come in various sizes, ranging from half an inch to 5 inches in diameter for residential applications. These pipes are lightweight, corrosion-resistant, and easy to cut and install.
Black ABS Pipes
Although less common, black acrylonitrile butadiene styrene (ABS) pipes are occasionally used for drainage systems. They share many properties with white PVC pipes but are more resistant to impact and cold temperatures.
Schedule 40 vs. Schedule 80
PVC pipes are classified by their wall thickness, with Schedule 40 and Schedule 80 being the most common:
- Schedule 40: Standard thickness for most residential applications
- Schedule 80: Thicker walls for increased pressure resistance, often used in industrial settings
CPVC Pipes
Chlorinated polyvinyl chloride (CPVC) pipes are different from standard PVC pipes. CPVC is designed to endure higher temperatures, making it ideal for hot water lines. It’s also safe for potable water distribution because of its enhanced durability and resistance to scaling and corrosion.
Foam Core PVC Pipes
Foam core PVC pipes integrate a foam layer between their inner and outer solid plastic layers. These pipes are particularly advantageous for non-pressurized systems, such as drainage, sewage, and venting applications. They are lighter and more efficient to install than traditional solid-wall PVC pipes.
Common PVC Fittings
PVC fittings help connect pipes and create a functional plumbing system. Here are some of the most common fittings you’ll encounter:
Couplings
Couplings are straight fittings you can use to join two pipes of the same diameter. They have shoulders on both sides to ensure proper pipe alignment.
Elbows
You can use elbows to change the direction of pipe runs. They come in various angles, including the following:
- 22.5-degree elbow
- 45-degree elbow
- 60-degree elbow
- 90-degree elbow (also known as a “quarter bend”)
Tees
Tees are T-shaped fittings you can use to connect three pipes. The most common type is the sanitary tee, which has a straight-through section and a branch at a 90-degree angle. This fitting is ideal for connecting sink drains to the main drain line.
Wyes
Wye fittings, shaped like the letter Y, are designed to connect three pipes at an angle. They provide a smoother transition for water flow than tees, making them less likely to clog. Wye fittings are particularly useful when you need to run a snake through your pipes to clear blockages.
Double Tees and Double Wyes
You can use double tee and double wye fittings to connect four pipes as follows:
- Double tees: Useful for connecting multiple sinks to the same drain line
- Double wyes: Provide better flow characteristics and are less likely to clog than double tees
Unions
Unions are versatile fittings you can remove and reattach without cutting the pipe. They are perfect for applications where you anticipate future disassembly or component replacements. Maintenance and repair are often simpler and less intrusive when using unions.
How To Measure PVC Pipe Size
When selecting PVC pipes, make sure to measure them correctly. Trethewey emphasizes in the video that PVC pipe sizes refer to their inside diameter, not the outside diameter. For example, a 1.5-inch pipe will have a one-and-a-half-inch inside diameter, while its outside diameter will be closer to 2 inches.
Follow these steps to measure PVC pipe size:
- Use a tape measure or caliper.
- Measure across the opening of the pipe.
- Round to the nearest standard size (1/2 inch, 3/4 inch, 1 inch, 1 1/2 inches, 2 inches, 3 inches, 4 inches).
Specialized PVC Fittings
In addition to standard fittings, there are specialized PVC fittings designed for specific applications. Here are some specialized fittings you might find:
Street Fittings
Street fittings, also known as spigot fittings, have one end that’s the same size as the pipe’s outside diameter. This allows for a direct connection to another fitting without needing a short pipe section, saving space in tight areas.
Cleanouts
Cleanout fittings provide access points for cleaning and maintaining the plumbing system. They typically have a removable cap you can unscrew to make way for a plumbing snake or other cleaning tools.
Reducers
Reducers connect pipes of different diameters. Depending on the specific application, they can be either concentric (centered) or eccentric (off-center).
Bushings
You can use bushings to reduce a pipe fitting’s diameter. Unlike reducers, you can insert bushings into other fittings to create smaller openings. Bushings are beneficial when you have limited space or need a clean, unobtrusive connection.
Tips for Working With PVC Pipes and Fittings
Keep the following tips in mind to ensure successful PVC plumbing system installation and maintenance:
- Allow sufficient drying time for cemented joints before testing or using the system.
- Always use the appropriate PVC cement and primer for joining pipes and fittings.
- Check local building codes to ensure compliance with regulations and standards.
- Consider using a deburring tool to smooth the edges of cut pipes for better fit and flow.
- Ensure all cuts are square and clean to promote proper sealing.
- Use support brackets or hangers to prevent sagging in horizontal pipe runs.
Identifying PVC vs. Other Pipe Materials
PVC is common in residential plumbing but is not the only pipe material you can use. Here are some tips to distinguish PVC from other pipe materials:
- Color: PVC is typically white or cream-colored, while ABS is black.
- Flexibility: PVC has some flexibility, while metal pipes are rigid.
- Markings: Look for printed information on the pipe, including material type, size, and pressure rating.
- Sound: Tapping PVC produces a hollow sound, while metal pipes sound more solid.
Comparison With PEX Pipes
Cross-linked polyethylene (PEX) pipes are another popular plumbing option. Unlike rigid PVC, PEX is highly flexible and often used for water supply lines. You can easily bend PEX pipes around corners and they don’t require as many fittings, making installation quicker. However, PEX is less resistant to UV light, so you should protect PEX pipes from direct sunlight.
Galvanized Steel Pipes
Older homes may still have galvanized steel pipes, which you can identify from their metallic finish. These pipes are durable but susceptible to corrosion and rust. They can also produce elevated lead levels in drinking water over time. As a result, many homeowners opt to replace galvanized steel with PVC or PEX for improved longevity and reduced maintenance.
Our Conclusion
Understanding PVC pipes and fittings is useful for any homeowner or DIY enthusiast tackling plumbing projects. By familiarizing yourself with the various types, sizes, and applications of PVC components, you’ll be better equipped to handle repairs, upgrades, or new installations in your home’s plumbing system. Always consult local building codes and, when in doubt, seek the advice of a professional plumber.
