1. What is SDR for HDPE Pipe?

SDR (Standard Dimension Ratio) is a method for rating pressure piping based on the geometry of the pipe. It represents the ratio of the outer diameter to the wall thickness of HDPE (High-Density Polyethylene) pipes.

2. How Does the Calculator Work?

The calculator uses the SDR formula:

Where:

• \( SDR \) — Standard Dimension Ratio (unitless)
• \( OD \) — Outer Diameter (mm)
• \( t \) — Wall Thickness (mm)

Explanation: The SDR value indicates the pressure rating capability of the pipe, with lower SDR numbers indicating thicker walls and higher pressure ratings.

3. Importance of SDR Calculation

Details: SDR is crucial for determining the pressure rating of HDPE pipes, ensuring proper material selection for specific applications, and maintaining system integrity under various operating conditions.

4. Using the Calculator

Tips: Enter the outer diameter and wall thickness in millimeters. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical SDR range for HDPE pipes?
A: Common SDR values range from 7.4 to 26, with each SDR corresponding to a specific pressure rating.

Q2: How does SDR relate to pressure rating?
A: Lower SDR numbers indicate thicker walls and higher pressure ratings. For example, SDR 11 pipes have a higher pressure rating than SDR 17 pipes.

Q3: Are there standard SDR values?
A: Yes, ISO and ASTM standards define specific SDR values that correspond to standardized pressure ratings for HDPE pipes.

Q4: Can SDR be used for pipe sizing?
A: Yes, SDR helps in selecting the appropriate pipe size and wall thickness for specific pressure requirements in various applications.

Q5: Is SDR calculation the same for all pipe materials?
A: While the SDR concept applies to various plastic pipes, the pressure ratings and material properties differ between HDPE, PVC, and other materials.