The Grazing Library
HDPE stands for High-Density Polyethylene. It is a durable, flexible plastic pipe commonly used for livestock watering systems, underground water distribution, and agricultural applications.
HDPE pipe is popular because it resists corrosion, accommodates some ground movement, and can be installed over long distances.
Not all HDPE pipe is sized the same way. Different sizing systems use different outside and inside dimensions.
IPS-OD pipe is sized according to standardized outside diameters. This is the sizing system used for USA Grazing Systems' 200 PSI SDR 11 HDPE water pipe.
IPS-OD fittings must be selected for the appropriate pipe outside diameter and application.
IPS-ID pipe uses an inside-diameter-based sizing convention and is commonly associated with SIDR pipe, including ASTM D2239.
IPS-ID fittings are designed for the appropriate IPS-ID pipe dimensions and should not be assumed interchangeable with IPS-OD fittings.
CTS-OD pipe uses copper-tube-size outside dimensions and is commonly associated with ASTM D2737.
CTS-OD fittings are designed for CTS-sized pipe and are not interchangeable with IPS-OD fittings of the same nominal size.
USA Grazing Systems' standard 200 PSI SDR 11 HDPE pipe uses the IPS-OD sizing system associated with ASTM D3035. Customers purchasing fittings for this pipe should choose compatible IPS-OD fittings, not IPS-ID or CTS-OD fittings.
SDR stands for Standard Dimension Ratio. It describes the relationship between a pipe's outside diameter and its wall thickness. SDR 11 means the outside diameter is approximately 11 times the nominal wall thickness.
For pipes of the same material and outside diameter, a lower SDR generally indicates a thicker wall.
Pressure ratings depend on the pipe material, temperature, applicable standard, and other factors—not SDR alone. USA Grazing Systems carries 200 PSI SDR 11 HDPE water pipe.
Not all compression fittings work with every type of HDPE pipe.
Before selecting fittings, confirm the pipe's sizing system, dimensions, and applicable specifications.
USA Grazing Systems offers Plasson and Philmac fittings for agricultural water systems. Choose the appropriate fitting series for your pipe rather than relying on nominal pipe size alone.
Not sure which pipe or fittings are right for your project? USA Grazing Systems is here to help you build a water system that works for your land and livestock.