Conversion from Cubic meters per second to Fluid ounces per hour

Information about the Cubic meter per second (m³/s)

The cubic metre per second is the SI unit of volumetric flow rate, equal to one cubic metre passing a point every second. Its symbol is m³/s, and hydrologists call it the cumec. As the coherent SI unit it needs no conversion factor: a velocity in metres per second multiplied by an area in square metres gives a flow directly in cubic metres per second.

Rivers are its natural subject. A small stream runs at a fraction of a cumec, the Thames at Kingston averages about 65, the Rhine at the Dutch border around 2,200, and the Amazon roughly 209,000 — a fifth of all the fresh water reaching the world's oceans. Flood warnings, abstraction licences and reservoir operating rules are all written in these numbers.

Hydroelectric power follows from the same figure. The power available is the flow multiplied by the head, by the density of water and by gravity, so 10 cubic metres per second falling 50 metres yields about 4.9 megawatts before losses. A turbine's rating and a river's flow-duration curve together determine how much of the year a station can run at full output.

Large ventilation and process equipment is rated here too. A road-tunnel fan moves tens of cubic metres per second, a power-station cooling-water pump tens more, and a blast furnace draws hundreds of cubic metres of air per second. Once the numbers reach this scale the cubic metre per second is more readable than any smaller unit.

The unit is also convenient because a cubic metre of water is a tonne. One cubic metre per second is therefore one tonne of water per second, which turns a flow into a force and a mass loading without further arithmetic — useful when sizing a spillway, a screen or a bridge pier.

Building services and hydrology sit awkwardly on either side of it. Ventilation engineers work in litres per second because their flows are a thousandth of a cumec, while river engineers would need six digits to express theirs in litres. The factor of a thousand between the two units is what keeps both trades in comfortable numbers.

One cubic metre per second equals 1,000 litres per second, 60 cubic metres per minute, or about 35.31 cubic feet per second.

Information about the Fluid ounce per hour (fl oz/h)

The fluid ounce per hour is a unit of volumetric flow rate equal to one imperial fluid ounce passing a point every hour. Its symbol is fl oz/h. An imperial fluid ounce is 28.413 millilitres, so an hour at this rate delivers about two tablespoons — a rate slow enough that it is measured by what has collected, not by what is moving.

Slow feeding and slow dosing account for most of its use. A drip feeder on a bird cage, a wick humidifier, a fragrance diffuser and a slow-release fertiliser injector on a greenhouse line all move liquid at a few fluid ounces per hour, and the reservoir capacity divided by that rate gives the interval between refills.

Domestic appliances are described by it in older British literature. A paraffin heater consumes a few fluid ounces per hour, a wick lamp rather less, and an oil-filled stove was once sold with its consumption stated exactly this way so that a household could calculate how long a gallon would last through a winter evening.

Evaporation and leakage measurements fall here too. Water lost from an open tank, brake fluid seeping past a seal, or condensate collected from a small cooling coil are all quantified per hour, because that is the shortest period over which enough accumulates to measure in an ordinary graduated cylinder.

The unit's usefulness lies in matching the observation to the human timescale. Nobody watches a drip for a second; a technician checks a container after an hour, a shift or a night, and expressing the rate per hour lets the observed volume be divided by the elapsed hours with no further arithmetic.

For orientation, 160 fluid ounces make an imperial gallon, so one fluid ounce per hour fills a gallon in a little under a week. Thirty-five fluid ounces per hour is about a litre per hour, and sixty fluid ounces per hour is one fluid ounce per minute.

One fluid ounce per hour equals about 28.41 millilitres per hour, about 0.02841 litres per hour, or about 0.01667 fluid ounces per minute.