bhp |
(brake horsepower)
The horsepower used by the fan. |

cfm |
(cubic feet per minute)
The volume of air moved per minute. If prefixed with an S, means standard or an A means actual. |

fpm |
(feet per minute)
The velocity of the airstream. |

Free Delivery |
The condition under which a fan operates when no static pressure or resistance is present. |

hp |
(horsepower)
The actual rated output of the fan motor used. |

ME |
(mechanical efficiency)
The ratio of power output to power input. |

rpm |
(revolutions per minute)
The number of times the fan shaft rotates per minute. |

Standard Air |
Dry air which weights .075 pounds per cubic foot at 70 degrees F. with a barometric pressure of 29.92 inches of mercury. |

SP |
(static pressure)
A measure of the force exerted by the fan in moving air through any air handling system. |

VP |
(velocity pressure)
The pressure corresponding to the average velocity determined from the volume of air moving through any air handling system. |

TP |
(total pressure)
The sum of the static pressure (SP) and the velocity pressure (VP) at any given point in the air handling system. |

psig |
pounds per square inch gauge. |

psia |
pounds per square inch absolute. |