| Fluid ounces per minute (fl oz/min) | Cubic feet per second (ft³/s) |
|---|---|
| 1 Fluid ounce per minute | 0.0000167232972133 ft³/s |
| 2 Fluid ounces per minute | 0.0000334465944265 ft³/s |
| 3 Fluid ounces per minute | 0.0000501698916398 ft³/s |
| 4 Fluid ounces per minute | 0.000066893188853 ft³/s |
| 5 Fluid ounces per minute | 0.0000836164860663 ft³/s |
| 10 Fluid ounces per minute | 0.000167232972133 ft³/s |
| 20 Fluid ounces per minute | 0.000334465944265 ft³/s |
| 25 Fluid ounces per minute | 0.000418082430331 ft³/s |
| 50 Fluid ounces per minute | 0.000836164860663 ft³/s |
| 100 Fluid ounces per minute | 0.00167232972133 ft³/s |
| Reference | Fluid ounces per minute (fl oz/min) | Cubic feet per second (ft³/s) |
|---|---|---|
| A domestic shower | 316.756 fl oz/min | 0.0052972 ft³/s |
| A kitchen tap | 351.951 fl oz/min | 0.00588578 ft³/s |
| A garden hose | 527.926 fl oz/min | 0.00882867 ft³/s |
| The Amazon river | 4.41346 × 1011 fl oz/min | 7380765 ft³/s |
The fluid ounce per minute is a unit of volumetric flow rate equal to one imperial fluid ounce passing a point every minute. Its symbol is fl oz/min. At 28.413 millilitres to the ounce, a minute at this rate delivers a small glass, which places the unit among the deliberate, controlled flows of food, drink and light industry.
Beverage dispensing is its steadiest employer. A post-mix drinks tower is set so that each nozzle delivers a fixed number of fluid ounces per minute, and the ratio of syrup to carbonated water — commonly one to five — is maintained by matching the two rates. A coffee machine's brew rate, a beer line's pour rate and a juice dispenser's throughput are all quoted this way.
Small dosing and metering pumps in food processing carry the same units. Flavourings, colourings, brines and preservatives are injected into a product stream at so many fluid ounces per minute, and the ratio to the main flow is what determines the finished recipe. A pump that drifts by five per cent changes the taste of every package made that shift.
Cleaning and chemical injection follow the same pattern. A dairy or brewery cleaning system meters detergent and sanitiser into circulating water at a rate in fluid ounces per minute, chosen so that the concentration in the loop matches what the supplier specifies for the temperature and contact time being used.
Laboratory and pilot-plant work in Britain and the Commonwealth still meets the unit in older equipment and older standard methods. Rotameters graduated in fluid ounces per minute remain in service, and a technician reading one must remember whether the scale is imperial or American, since the two ounces differ by four per cent.
For orientation, 60 fluid ounces per minute is one fluid ounce per second, 35 fluid ounces per minute is about a litre per minute, and 160 fluid ounces make an imperial gallon. So a dispenser running at 32 fluid ounces per minute fills a gallon in five minutes exactly.
One fluid ounce per minute equals about 28.41 millilitres per minute, about 0.02841 litres per minute, or about 0.01667 fluid ounces per second.
The cubic foot per second is a unit of volumetric flow rate equal to one cubic foot passing a point every second. Its symbol is ft³/s, and in hydrology it has a name of its own: the cusec. One cusec is about 28.32 litres per second, roughly the flow of a vigorous garden hose or a small brook.
American river gauging is entirely built on it. The United States Geological Survey publishes stream flow in cubic feet per second at thousands of gauges, water rights in the western states are granted in cusecs, and the Colorado's allocations between states rest on figures first written in this unit a century ago. The Mississippi at its mouth averages about 600,000 cubic feet per second.
Irrigation districts inherited it from the same tradition. A miner's inch, an older western measure, is defined in most states as a fixed fraction of a cusec, and a canal headgate is set to deliver a farmer's entitlement in cubic feet per second for a stated number of hours. The product of the two is the acre-foot, the volume unit that follows naturally from the cusec.
An easy approximation makes the unit memorable: one cubic foot per second flowing for twenty-four hours delivers almost exactly two acre-feet — 1.983, to be precise. Irrigation engineers use the round figure daily, since it converts a rate into a seasonal water budget in a single step.
Flood hydrology is written in it too. A design storm on a small catchment might produce a few hundred cubic feet per second, a major river flood tens or hundreds of thousands, and culverts, bridges and levees in the United States are sized against a peak discharge expressed exactly this way.
Its metric counterpart is the cubic metre per second, which is 35.31 times larger. Hydrological literature moves constantly between the two, and the ratio is worth remembering: a hundred cusecs is a little under three cubic metres per second, and a thousand cubic metres per second is a large river in anyone's units.
One cubic foot per second equals about 28.32 litres per second, about 0.02832 cubic metres per second, or about 448.8 US gallons per minute.