Loading Units to Litres per Second (L/s) Converter

This calculator converts plumbing Loading Units (LU) into a Probable Demand Flow Rate (litres per second) in accordance with standard plumbing design methodology.

The calculation is based on Loading Unit values defined in the Plumbing Engineering Services Design Guide, as published by the Institute of Plumbing. These values are commonly used to assess diversified water demand in residential and commercial installations.

Enter the quantity of each outlet type to determine:

  • Total Loading Units per dwelling

  • Combined Loading Units for the building

  • Probable Demand Flow Rate (L/s)

Note: In buildings such as leisure centres or sports facilities where simultaneous use of showers and washing appliances is expected, Loading Units may not be applicable. In such cases, the full flow rate of the appliances should be used.

Loading Units to L/s Converter
This tool calculates the Probable Demand Flow Rate (L/s) from standard plumbing Loading Units, based on guidance from the Institute of Plumbing. It is suitable for residential and commercial water demand assessment where diversified flow applies.

Shortened Technical Variant

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FLOW RATE CALCULATOR

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Fixture Count

Enter the number of each fixture type in your system:

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PRESSURE REQUIREMENT

Vertical height from pump to highest outlet
Estimated pressure loss in pipework (allow 2-5m for small systems)
Typically 10-15m for good flow (1 bar = 10.2m)
Pressure Requirement
0.0 m
Total Required Head

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Photos of existing pump, nameplate, or plant room

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How It Works
  1. Calculate: Enter your fixtures and pressure requirements
  2. Submit: Send your enquiry with optional photos
  3. Review: Our engineers assess your needs (within 24 hours)
  4. Consult: We contact you to discuss solutions
  5. Quote: Receive a tailored proposal
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  • Full supply & installation service
  • Bespoke and off-the-shelf solutions
  • Minimal downtime installations
  • 20+ years of engineering experience

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Call: 0116 3735496

Email: info@ntclokepumpsandwater.co.uk