Inventory is not flow
Pipe hold-up is the geometric liquid volume inside a length of pipe. Flow is volume per unit time. Pressure demand depends on the route resistance, elevation and connected equipment at that flow. The inventory calculator is useful for a requirements brief, but it is not a pump-selection tool.
Evaluate the complete circuit
Include the supply path, equipment, return path, valves and instruments in the calculation. For tank cleaning, use the cleaning-device supplier’s inlet duty. For parallel branches, examine flow distribution rather than assuming a common header measurement proves every branch.
Concurrent circuits need a separate case
If multiple duties operate at once, assess supply, return, heating and shared utility requirements for that combination. A system connected to six circuits may clean only one at a time; the total connected count does not define peak demand.
Technical context
Industry context: Tetra Pak Dairy Processing Handbook — cleaning dairy equipment. This reference provides technical context for cleaning-circuit design; it does not certify or guarantee an equipment configuration.