Estimated reading time: 4 minutes
A Quick Guide for Homeowners
Knowing the difference between various PVC pipe types can make your job easier when it comes to DIY plumbing or simply understanding your home’s infrastructure. You’ll encounter two common types of PVC pipes: DWV (Drain, Waste, and Vent) and Schedule 40.
Here’s a detailed guide to help you identify and understand them.
DWV vs. Schedule 40: What’s the Difference?
DWV (Drain, Waste, and Vent):
- Purpose:
DWV pipes are used for low-pressure applications to drain wastewater and vent sewer gases. They are not designed to handle pressurized water. - Appearance:
These pipes typically have thinner walls than others and are often labeled “DWV.” Foam core DWV pipes have a distinctive lightweight feel. - Common Locations:
DWV pipes are usually found in bathrooms, kitchens, and basement drain systems.
Schedule 40:
- Purpose:
Schedule 40 pipes are designed for higher-pressure applications. They are commonly used in water supply lines and can handle pressurized flow effectively. - Appearance:
These pipes have thicker walls than DWV pipes and are usually labeled “Sch 40.” They often feel sturdier and heavier. - Common Locations:
Schedule 40 pipes are found in under-sink plumbing, water lines inside walls, and connections to water heaters.
How to Tell Them Apart
If you’re unsure which pipe you’re dealing with, here are some easy ways to figure it out:
- Markings on the Pipe:
Look for clear labels like “DWV,” “Sch 40,” or “Foam Core.” These markings are the easiest way to identify the type of pipe. - Wall Thickness by Feel:
While you don’t need special tools, comparing two pipes side by side can help. Schedule 40 feels much sturdier and thicker than DWV, while Foam Core DWV feels noticeably lighter and thinner. - Weight Check:
Hold a similar length of each pipe. Schedule 40 is the heaviest, solid core DWV is in the middle, and Foam Core DWV is the lightest. - Application Clues:
Think about where the pipe is located. Pipes in drain, waste, or vent systems are likely DWV, while those connected to water lines or carrying pressurized water are usually Schedule 40.
Spotlight on Foam Core DWV
Foam core DWV pipes are a lighter, cost-effective alternative to solid core DWV pipes. They consist of a foam core sandwiched between two solid PVC layers. However, they are strictly limited to non-pressure systems, making them ideal for drainage. You’ll often find foam core DWV pipes in newer homes as a more economical option.
Pro Tips for Homeowners
- Avoid Mixing Pipe Types: Schedule 40 and DWV pipes are not interchangeable. Always use the appropriate pipe for the intended application.
- Invest in Tools:
- A PVC cutter (for making cuts in tight places)
- A miter box or hack saw works best for keeping cuts square
- Deburring Tool and 80-grit sandpaper
- Primer/cement for PVC
- Utility knife
- Hack Saw or PVC saw
- Follow Local Codes: Plumbing codes vary by region, so check with local authorities. Here is a state-by-state breakdown to help you ensure compliance.
- My Local: Ridgeland, Mississippi, follows the International Plumbing Code (IPC), which is established by the International Code Council (ICC).
A Word of Caution
While this guide equips you with essential knowledge, plumbing is a complex system. Missteps can lead to leaks, water damage, or code violations. Consulting a licensed plumber is highly recommended for larger or more complicated projects.
Why This Matters
Understanding the types of PVC pipes in your home not only empowers you to tackle small repairs but also ensures you’re using the right materials for the job. This knowledge can save you time, money, and potential headaches in the future.
Additional Resources
- International Association of Plumbing and Mechanical Officials (IAPMO)
- Uniform Plumbing Code (UPC)
- PVC Pipe Association
Remember, knowledge is your first tool in any DIY project!
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