Search results
Results from the WOW.Com Content Network
Air changes per hour, abbreviated ACPH or ACH, or air change rate is the number of times that the total air volume in a room or space is completely removed and replaced in an hour. If the air in the space is either uniform or perfectly mixed, air changes per hour is a measure of how many times the air within a defined space is replaced each hour.
A normal cubic meter (Nm 3) is the metric expression of gas volume at standard conditions and it is usually (but not always) defined as being measured at 0 °C and 1 atmosphere of pressure. A standard cubic foot (scf) is the USA expression of gas volume at standard conditions and it is often ( but not always ) defined as being measured at 60 ...
Gases are compressible, which means that a figure in cubic feet per minute cannot necessarily be compared with another figure when it comes the mass of the gas. To further confuse the issue, a centrifugal fan is a constant CFM device or a constant volume device. This means that, provided the fan speed remains constant, a centrifugal fan will ...
atmosphere-cubic foot per hour: atm cfh [citation needed] ≡ 1 atm × 1 cu ft/h = 0.797 001 247 04 W: atmosphere-cubic foot per minute: atm cfm [citation needed] ≡ 1 atm × 1 cu ft/min = 47.820 074 682 24 W: atmosphere-cubic foot per second: atm cfs [citation needed] ≡ 1 atm × 1 cu ft/s = 2.869 204 480 9344 × 10 3 W: BTU (International ...
Yet other definitions are in use for industrial gas, [5] where, in the US, a standard cubic foot for industrial gas use is defined at 70 °F (21.1 °C) and 14.696 psia (101.325 kPa), while in Canada, a standard cubic meter for industrial gas use is defined at 15 °C (59 °F) and 101.325 kPa (14.696 psia).
Cubic decimetre the volume of a cube of side length one decimetre (0.1 m) equal to a litre 1 dm 3 = 0.001 m 3 = 1 L (also known as DCM (=Deci Cubic Meter) in Rubber compound processing) Cubic centimetre [5] the volume of a cube of side length one centimetre (0.01 m) equal to a millilitre 1 cm 3 = 0.000 001 m 3 = 10 −6 m 3 = 1 mL Cubic millimetre
The instrument that measures airflow is called an airflow meter. Anemometers are also used to measure wind speed and indoor airflow. There are a variety of types, including straight probe anemometers, designed to measure air velocity, differential pressure, temperature, and humidity; rotating vane anemometers , used for measuring air velocity ...
Environmental agencies in the USA often use the terms "dscf" or "scfd" to denote a "standard" cubic foot of dry gas. Likewise, they often use the terms "dscm" or "scmd" to denote a "standard" cubic meter of gas. Since there is no universally accepted set of "standard" temperature and pressure, such usage can be and is very confusing.