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Decoding Schedule, Class, And SDR Pipe Markings

As you prepare to install a sprinkler system, you might use PVC or polyethylene tubing to deliver water to the sprinkler head. Selecting the right material for your system’s framework ensures lasting and efficient operation.

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PVC Ratings: Schedule vs Class

PVC pipe is rated by two different systems. The first is the class system, or CL, and the other is the schedule system, SCH. The code on the side of the pipe is required by law. It indicates the properties and tolerances associated with the pipes manufacturer. There is no established color code for PVC pipe. So, the only way to know exactly what kind of plastic pipe you are working with is to understand what the markings mean.

What Do The Numbers On PVC Pipe Mean?

Here’s how you decode the industry nomenclature. The outside of all plumbing grade PVC pipe is labeled with the following information:

  • Manufacturer of the pipe
  • The standard the pipe conforms to
  • The pipe size
  • Its pressure rating
  • The schedule number
  • A laboratory seal or mark if it is to be used for potable water

What Is SDR In Plastic Pipe

Poly pipe is rated by a system of SDR ratios (Standard Dimensional Ratios), sometimes labeled just DR. The lower the SDR number the stronger the tube is. HDPE poly is commonly rated for 80, 100, 160, 200, and 250 PSI operating pressure. The least expensive form of poly is sold as irrigation pipe and is rated for 60, 80, or sometimes 100 PSI. It is commonly used for low-pressure laterals on irrigation systems. All poly tube of the same size will have the same inside diameter.

Thank you for watching this video about how to select pipe and tubing for your sprinkler system. Remember, Sprinkler Warehouse has everything for your irrigation needs so that your trees, lawns, flowerbeds, and gardens are lush and beautiful. If you have any questions about our products chat with one of our superb customer service agents on They really know their stuff, and they’ll get you squared away.

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For Sprinkler Warehouse, I’m Alfred Castillo. Your Sprinkler Warehouse Pro!