Flow Calculator

1. Select the flow velocity and internal diameter according to the required flow rate.
2. Select the appropriate SDR according to your application, this reflects the ratio of pipe diameter to wall thickness.
3. Apply the below formula to find the required external diameter, ensuring compatibility with the piping specification.
4. Determine the pressure loss (bar) in the straight pipe section by selecting the pipe length (m)

This calculation is vital for confirming that your pipe selection meets the capacity required for the intended flow rate and for ensuring safe and efficient operation of your piping system.

Choosing the proper flow velocity is crucial for optimal performance and longevity of your piping system. The appropriate flow velocity depends on the application and the location within the system:

• Suction side (pipes drawing fluid into pumps or similar equipment): Recommended flow velocity: **0.5 – 1.0 m/s** Lower velocities minimize the risk of cavitation and ensure stable pump operation.
• Pressure side (pipes carrying fluid after a pump or pressurized source): Recommended flow velocity: **1.0 – 3.0 m/s** Higher velocities are acceptable due to increased pressure, but should still be controlled to avoid noise, vibration, and excessive wear.

Maintaining these standard velocity ranges helps reduce the risk of erosion, noise, and pressure surges, while promoting system efficiency and reliability.

To find the outside diameter using the inside diameter and the applicable SDR (Standard Dimension Ratio), use the following formula:

Where:

• d = outside diameter of the pipe
• di = inside diameter of the pipe 
• SDR = Standard Dimension Ratio (a measure of pipe wall thickness)

SDR is the ratio of the pipe’s outer diameter to its wall thickness (SDR = D / s).

• Lower SDR (e.g., SDR 11): Thicker walls, higher pressure rating, but slightly reduced internal flow area.

• Higher SDR (e.g., SDR 17): Thinner walls, lower pressure rating, but larger internal flow area.

Select the SDR that matches your system’s pressure requirements.

Yes. The tool is designed for both planning new installations and analyzing existing ones. It provides reliable results to support decision-making for optimization and retrofitting.

Yes. The calculator is specifically designed for engineers, planners, and project managers working on both industrial and infrastructure plastic piping systems. It supports applications such as water supply networks, wastewater systems, irrigation, district cooling and heating, and other large-scale utility projects where accurate pipe sizing and pressure performance are critical.

By accounting for parameters such as pipe dimensions, SDR, and pressure requirements, the tool helps ensure that selected piping solutions meet safety standards, regulatory requirements, and long-term reliability expectations. This makes it suitable for use during feasibility studies, preliminary design, detailed engineering, and project planning phases.

Whether you are designing municipal infrastructure, utility distribution systems, or large commercial installations, the calculator provides quick, reliable guidance to support informed decision-making and efficient system design.

Plastic piping systems generally offer superior flow characteristics due to their smooth internal surfaces. While new steel pipe has a roughness of approximately 0.045 mm, plastic is significantly smoother (approximately 0.0015 mm). This results in lower pressure loss and reduced energy consumption for pumps over the system’s lifespan.