Air Properties & Psychrometrics
The arcing lines on a psychrometric chart represent the ____
What are constant relative humidity levels
An anemometer that measures airflow velocity using a small propeller is called a ____
What is a vane anemomete
Filters that use an activated-charcoal form to remove odors and gases are called ____
What are carbon filters
Diffusers in air distribution systems do this with the air leaving the duct.
What is spread the air more uniformly than registers
The measurement of a material's resistance to heat transfer is known as its ____
What is R-value
The heat released when moisture condenses out of the air is called this type of heat
What is latent heat
The outer tube of a pitot tube has holes on the side and measures only the ____ pressure
What is static pressure
These high-efficiency filters are commonly used to remove very small particles
What are HEPA filters
Automatic fire dampers should be installed in all ____ ducts in commercial and industrial buildings
What are vertical ducts
A measure of heat transfer that includes an adjustment for boundary air films is called the ____
What is U-value
The approximate summer comfort dry-bulb temperature listed with 50% relative humidity
What is 75°F
The instrument used to pressure test a central HVAC system's ductwork
What is a duct blaster
Filters that use an electrostatic charge produced by the friction of air blowing across the fibers are called ____
What are passive electrostatic filters
Fans used in air distribution systems are usually these types
What are axial flow or radial flow
Reducing sun loads can be accomplished by installing awnings, glass with heat-reflecting qualities, or special heat-absorbing glass. Which is correct
What are all of the above
The amount of time it takes for heat to travel through a substance heated on one side is called ____
What is heat lag
Total air pressure equals static air pressure plus this other pressure
What is velocity pressure
Ultraviolet lights installed in ductwork are frequently used to reduce ____
What are bacteria, mold spores, and viruses
If there is more return air than supply air in a room, the room will have this pressure
What is negative pressure
If the rooms in a building are tightly sealed, HVAC systems should be designed to do this
What is admit fresh air into the building
A natural passage of air leaving a building through doors, windows, and other construction joints is called ____
What is exfiltration
The instrument used to measure the total airflow of a central HVAC system (commonly at outlets) is the ____
What is a flow hood
The ASHRAE standard that includes minimum ventilation rates to result in acceptable indoor air quality is ____
What is ASHRAE Standard 62
Smoke from smoke sticks, smoke guns, or smoke candles can be used to ____
What is determine the amount and direction of a draft, check air movement, and locate air leaks
An ERV is used most appropriately in colder climates and where humidity control is important — what is an ERV
What is an energy recovery ventilator