Eiffel Trading 101: SDR for HDPE Pipe

High-density polyethylene (HDPE) pipe is commonly used to transport water, often in dewatering and dredging operations. HDPE pipe is chemical and UV-resistant, can withstand temperatures from -200 to 180 Fahrenheit. It’s also a type of construction material that can be reused if in good condition, with a service life of more than 50 years.

HDPE pipe is less costly to transport and install than steel due to its lower weight. It’s ideal for water transportation because the heat fusion process by which pipes are connected creates leak-free joints. HDPE even has its own pressure rating system.

If you view our listings of used HDPE pipe for sale, you’ll see that many list “SDR”, followed by a number, in the headline. So, what is SDR for HDPE pipe?

SDR stands for “standard dimension ratio”, and is used to rate pressure piping. It’s an inverse relationship, though. The higher the SDR, the lower the pressure rating. SDR indicates the amount of pressure (in PSI) a HDPE pipe can withstand.

Determining an HDPE pipe’s SDR is fairly simple. The formula is SDR = D/s, where ‘D’ is the outside diameter of the pipe (in millimeters or inches), and ‘s’ is the thickness of the pipe wall (in millimeters or inches). In the example below, a 4-inch pipe has an outside dimension (OD) of 110mm. We have calculated the SDR based on various wall thicknesses.

In the graphic above, we used a sample 4-inch HDPE pipe, with SDR ratings of 9, 11 and 17. You can see that, as SDR decreases, the thickness of the wall increases. A pipe’s tensile strength increases as its thickness increases, which is the pipe’s ability to stand up under pressure.

You may also have heard the term “DR”, which stands for “dimension ratio”. When a pipe’s dimension ratio is one of the following, it’s considered standard, which is recognized internationally. Standard dimension ratios fall along the ANSI preferred number series and include 9, 11, 13.5, 17, 21, 26, and 32.5. All SDRs are DRs, but not all DRs are SDRs.

Keep in mind that pipe measurements may vary from manufacturer to manufacturer.

Now that you know what SDR is, it’s time to start planning your next project. Check out our selection of used HDPE pipe.

Buy and Sell Used and Surplus HDPE Pipe with Eiffel Trading

From used formwork and used drill rigs to used sheet pile and used wide flange beams, our online marketplace has it all.

All of our listings are constantly being updated, but if you don’t see what you’re looking for, create a wanted listing for free.

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If you have any questions or would like additional information, please call us at 1-800-541-7998 or email sales@eiffeltrading.com.