Foot-pound-second system

F.P.S. system n. The foot-pound-second system of units. The British system of physical units derived from the three fundamental units of length, mass, and time, i.e., the foot, pound, mass, and the second. 

Together with the SI system, two other unit systems commonly used are the cgs (centimeter-gram-second) and the fps (foot-pound-second). While the cgs system was essentially supplanted by SI units (also termed mks), the fps system is still in use in different parts of the world and most notably in the United States. Conversion between the cgs and SI systems is generally straightforward— usually a factor of 10 or 1000 is involved. Conversion between s (also known as the Imperial system of units) and SI is more complicated. 

In the foot-pound-second or fps system (which is ft-lb(mass)-s), the Reynolds number is properly calculated using the following units ... 

FPS Foot-Pound-Second British absolute system of units,... 

In producing a third edition, we have taken the opportunity, not only of updating the material but also of expressing the values of all the physical properties and characteristics of the systems in the SI System of units, as has already been done in Volumes 1 and 3. The SI system, which is described in detail in Volume 1, is widely adopted in Europe and is now gaining support elsewhere in the world. However, because some readers will still be more familiar with the British system, based on the foot, pound and second, the old units have been retained as alternatives wherever this can be done without causing confusion. 

In the cgs system, power has the units of ergs per second in the mks system, units of joules per second lor watts) and in the English system, units of foot-pounds per second. A common engineering unit is the horsepower, defined as 550 foot-pounds per second or 33.000 footpounds per minute. The SI unit of power is the wall. I watt = I joule per second. < I joule is the work done by I newton acting through a distance of I meler.l I joule = watt-second = I07 ergs= I07 dyne-centimeters. The SI unil of force is the newton. (I newton = 10s dynes). See also entry on Units and Standards. 

The egr system of units, based on the centimeter, gram, and second as units in mechanics, is a metric system which continues to be used in some branches of physics In daily life, the customary units in the United States are those based on the foot, pound-force, and second, but these units are... 

FPS. The system of units based on the fundamental units of the English system foot, pound and second. 

FIG. 14-53 Pressure for metal Intalox saddles, sizes No, 25 (nominal 25 mm) and No, 50 (nominal 50 mm). Air-water system at atmospheric pressure, 760-mm (30-in) column, hed height, 3,05 m (10 ft), L = liquid rate, kg/(s-m ). To convert kilograms per second-square meter to pounds per hour-square foot, multiply hy 151,7 to convert pascals per meter to inches of water per foot, multiply hy 0,1225, (Coutiesy Notion Company, Akron, Ohio.)... 

FIG. 14-54 Pressure drop for Flexipac packing, sizes No, 1 and No.. 3, Air-water system at atmospheric pressure. Liquid rate in gallons per minute-square foot. To convert (feet per second) (younds per cubic foot) " to (meters per second) (kilograms per cubic meter) " , multiply by 1,2199 to convert gallons per minute-square foot to pounds per hour-square foot, multiply by 500 to convert inches of water per foot to millimeters of water per meter, multiply by 83,31 and to convert pounds per hour-square foot to kilograms per second-square meter, multiply by 0,001.356, Coutiesy Koch Engineering Co., Wichita, Kansas.)... 

In the SI system a typical set of units for the parameters would be p. in kilograms per second per meter, cp in kilojoules per kilogram per Celsius degree, and k in kilowatts per meter per Celsius degree. In the English system one would typically employ p. in pound mass per hour per foot, cp in Btu per pound mass per Fahrenheit degree, and k in Btu per hour per foot per Fahrenheit degree. 

The base units of the American engineering system are the foot (ft) for length, the pound-mass (Ibm) for mass, and the second (s) for time. This system has two principal difficulties. The first is the occurrence of conversion factors (such as 1 ft/12 in), which, unlike those in the metric systems, ate not multiples of 10 the second, which has to do with the unit of force, is discussed in the next section. 

---