Imperial Gallons per Hour (imp-gal/h) to Gallons per second (gal/s) conversion

What is the Imperial Gallon per Hour?

The imperial gallon per hour (imp-gal/h) is a unit of volumetric flow rate expressing how many imperial gallons of fluid pass a point in one hour. It is used in the UK and other Commonwealth countries for pumps, fuel consumption, and plumbing flow ratings.

Definition

One imperial gallon per hour equals one imperial gallon of volume divided by one hour (3,600 seconds):

$$1\ \text{imp-gal/h} = 0.00126280\ \text{l/s}$$

The imperial gallon is defined as exactly 4.54609 litres, so dividing by 3,600 seconds gives 4.54609 / 3600 = 0.00126280 L/s (equivalently 4.54609 L/h).

Origin and History

The imperial gallon was established by the British Weights and Measures Act of 1824, originally defined as the volume of 10 pounds of water at a specified temperature. It was later fixed by reference to the litre. The "per hour" rate arose naturally in the 19th and 20th centuries as a practical measure for pump throughput and fuel usage, hours being a convenient interval for slow, steady flows.

Law and Notable Facts

The imperial gallon (4.54609 L exactly) is legally distinct from and about 20% larger than the US liquid gallon of 3.785411784 L. As a result an imperial gallon per hour is likewise about 20% greater than a US gallon per hour. Since UK metrication, the imperial gallon is no longer a primary trade unit but persists in fuel-economy figures (miles per gallon) and equipment specifications.

Real-World Examples and Conversions

• A small garden or aquarium pump rated at 100 imp-gal/h moves about 454.6 litres of water every hour, roughly 0.126 L/s.
• A domestic tap running at 1 imperial gallon per hour is a bare trickle of about 4.55 L each hour.
• 1 imp-gal/h ≈ 0.833 US gal/h, reflecting the larger imperial gallon.
• A pump moving 220 imp-gal/h delivers about 1,000 L/h, or roughly 0.278 L/s.

What is Gallons per Second (GPS)?

Gallons per second (GPS) is a measurement unit that tells you how many gallons of a liquid are moving past a certain point every second. It's a rate, showing volume over time. It is commonly used in the US to measure high volume flow rates.

How is GPS Formed?

GPS is formed by dividing a volume measured in gallons by a time measured in seconds.

$$GPS = \frac{Volume (Gallons)}{Time (Seconds)}$$

For example, if 10 gallons of water flow out of a pipe in 2 seconds, the flow rate is 5 gallons per second.

Conversions and Relationships

GPS can be converted to other common flow rate units:

• 1 Gallon ≈ 0.00378541 Cubic Meters
• 1 GPS ≈ 0.00378541 $m^3/s$
• 1 GPS ≈ 3.78541 Liters/second

Real-World Applications and Examples

• Firefighting: Fire hoses and sprinkler systems are often rated in GPS to indicate their water delivery capacity. A typical fire hydrant might deliver 500-1000 GPS.
• Pumping Stations: Large pumping stations, such as those used in water treatment plants or flood control, can have flow rates measured in thousands of GPS.
• Industrial Processes: Many industrial processes, such as chemical manufacturing or oil refining, involve the movement of large volumes of fluids, and GPS is used to measure flow rates in these processes.
• River Flow: While not a direct measurement, river discharge rates can be expressed in terms relatable to GPS (e.g., converting cubic feet per second to GPS for easier understanding).
  • The average flow rate of the Mississippi River is around 600,000 cubic feet per second, which is approximately 4.5 million GPS.
• Pool filling: Average garden hose has 5-10 gallons per minute. This means it will take around 30 minutes to fill a 150 gallon pool. This is 0.08 - 0.17 GPS.

Historical Context and Interesting Facts

While no single person is specifically associated with the "invention" of GPS as a unit, its use is tied to the development of fluid mechanics and hydraulics. Understanding flow rates became crucial with the rise of industrialization and the need to efficiently manage and transport fluids.

The measurement of flow rates dates back to ancient civilizations that developed aqueducts and irrigation systems. However, the standardization of units like GPS is a more recent development, driven by the need for precise measurements in engineering and scientific applications.