Air Distribution Systems Flashcards
What is a type of fan or blower with a blade design that is self-cleaning and a good choice for air containing a lot of dust or grease?
Radial
What do air systems used only for heating generally require?
Less airflow than systems used for cooling
What is the air pressure applied to every square inch of the Earth’s surface at sea level?
14.7 psia
Where is the lowest pressure level in an air distribution system found?
Blower inlet
Which instrument provides a direct reading of relative humidity?
Hygrometer
What can be calculated by Fan Law 1 when a change in the volume of airflow is known?
A new value for rpm
What is a characteristic that helps distinguish fans from blowers?
The air flow is normally parallel to the shaft of a fan
How is the smoke damper that provides the minimum amount of leakage rated?
Class 1
What is the function of a damper in an air distribution system?
Controls and balances air flow
What is an untrue statement regarding air system fittings and transitions?
They have the same pressure loss per foot as the same size of straight duct
What does the plastic or foil sleeve on the outside of a branch duct in crawl space serve as?
Vapor barrier
What is the maximum length of the trunk duct in an extended plenum syster?
24’
Overhead trunk and radial systems are typically used in what type of homes?
Homes built on concrete slabs.
What do air distribution systems with high sidewall outlets generally do?
Favor cooling over heating
What is the duct with the lowest resistance to airflow?
Metal duct with exteriour duct wrap
