Selecting the correct pipe is essential to ensure long service life, safety, and performance of your plumbing system. The POLYMELT / POLYMUTAN working pressure chart helps you choose the most suitable pipe based on temperature, pressure, and service life requirements, with all values calculated using a safety factor of 1.25.

1. Identify the Operating Temperature

Start by determining the maximum water temperature in your system.
As temperature increases, the allowable working pressure of the pipe decreases.
Always select the pipe based on the highest operating temperature expected.

2. Define the Required Service Life

The chart provides pressure ratings for different operating periods (1, 5, 10, 25, and 50 years).
For most residential and commercial installations, a 50-year operating life is recommended to ensure long-term reliability.

3. Determine the System Working Pressure

Calculate the maximum working pressure of your system, including:

• Pump pressure
• Static water head
• Possible pressure fluctuations

This value must always be lower than the maximum service pressure shown in the chart.

4. Select the Pipe Type and SDR Class

Compare your system requirements with the chart values for:

• POLYMUTAN SDR 6 – highest pressure resistance (thicker wall)
• POLYMUTAN SDR 11
• POLYMUTAN ML5 SDR 7.4
• UV ML5 SDR 7.4 – suitable for applications exposed to UV radiation

Choose a pipe whose rated pressure at the selected temperature and service life exceeds your system pressure.

5. Final Verification

All values in the chart already account for:

• Long-term stress behavior
• Safety factor of 1.25
• Compliance with drinking water standards

This ensures a safe and durable installation when selected correctly.

Example

Why This Matters

Correct pipe selection:

• Prevents premature failure
• Ensures long-term performance
• Reduces maintenance and replacement costs
• Guarantees safety under real operating conditions