Construction Machinery & Attachments worked example

Hydraulic Flow Requirement with attachment rated hydraulic flow of 14 units: a worked example

This worked example runs the hydraulic flow requirement numbers for a tougher week than the baseline: attachment rated hydraulic flow of 14 units instead of the typical 28 units. Estimate hydraulic flow demand for construction attachments from tool flow, duty multiplier, and operating time.

The inputs for this scenario

  • Attachment rated hydraulic flow: 14 units (the input this scenario stresses; the baseline uses 28)
  • Duty cycle and pressure-loss multiplier: 1.18 x (held at the documented default)
  • Operating time: 6 hr (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Adjusted hydraulic flow requirement = attachment rated hydraulic flow × duty cycle and pressure-loss multiplier.
  • adjusted hydraulic flow requirement works out to 16.52 gpm at these inputs, and this is the headline figure for the scenario.
  • flow demand per operating hour reference works out to 2.75 gpm / hr at these inputs.
  • attachment rated hydraulic flow works out to 14 gpm at these inputs.
  • duty cycle and pressure-loss multiplier works out to 1.18 x at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where attachment rated hydraulic flow sits at 28 units and the headline result is 33.04 gpm, this scenario comes in 50% below the baseline at 16.52 gpm.
  • Use it before pairing an attachment to a carrier, or when troubleshooting an attachment that runs hot or sluggish. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • adjusted hydraulic flow requirement: 16.52 gpm (headline result)
  • flow demand per operating hour reference: 2.75 gpm / hr
  • attachment rated hydraulic flow: 14 gpm
  • duty cycle and pressure-loss multiplier: 1.18 x

Run it with your numbers

  • To rerun this with your own numbers, open the live Hydraulic Flow Requirement calculator, set attachment rated hydraulic flow to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.