Hydraulic flow capacity
A flow figure without a head figure is not a duty point.
What runs out
Pumped flow available to the technology cooling loop at the system's actual resistance.
The relation that governs it
Required flow ≈ rack count × platform flow per rack. Around 1.45 l/min per kW at a 10 K delta-T is a reasonable screening figure; the platform's own published flow per rack is better.
Worked example
What flow do 20 racks need?
20 × 130 l/min
2600 l/min
Check it against available head, not only against pump capacity.
Reproducible by hand. A page that asks you to trust a number has taught you nothing.
How to tell whether it binds in your hall
Multiply target racks by the platform's flow per rack and compare against installed pumped capacity — then check available head against the resistance the new loop adds. Halls pass the first test and fail the second.
What relieves it
Pump replacement or addition, and pipework where the resistance is in the distribution rather than the pumps.
What that relief costs beyond money
Head is where retrofits are caught out. Adding flow to a loop whose resistance has risen gives a duty point nobody modelled.
Indicative relief lead time
12–36 weeks
European retrofits. The schedule, not the capex, usually decides.
The mistake we actually see
Flow capacity quoted from the pump nameplate rather than from the duty point of the system as it will be built.
Basis
- — OCP fluid guidelines; site hydraulic records.
These usually travel together
Does this one bind in your hall?
Seven numbers you already know, all thirteen constraints evaluated, and the one that stops you first named with its basis in engineering units. Free.