Study Guide Unit 34
HEPA filters can filter to a very high efficiency, down to a(n) ___ micrometers-sized particle or lower
0.3
What are the relative humidity limits recommended for residences?
40%-60%
The American Society for Heating, Refrigrration, and Air Conditioning Engineers (ASHRAE) has guidelines governing indoor air quality. These guidelines are called ASHRAE Standard ___
62.1-2013
Air in homes tends to be drier in the winter. Why?
Air at lower temperatures in the winter infiltrates in the house. As the air is raised in temperature, it expands. The portion of the total volume the moisture occupies is less and the relative humidity is lower because air with higher temperatures can hold more moisture.
___ filters gave large surface area and require a deep filter case.
Cube
How can the installation of a humidifier help to reduce heating cost
Dry air causes the person to feel cold, due to water evaporation from the skin, and to set the thermostat a few degrees higher to become comfortable, thus consuming more heating energy.
People who are active and spend a great deal of time outdoors are more likely to experience the effects of pollution. T/F
False
The humidifier should exhaust directly onto air filters and electronic air cleaners. T/F
False
Why are HEPA filters desirable
HEPA filters are desirable since they can trap particles that can contain mold, dust mites, pollen, and bacteria.
What is the major objection to using an atomizing humidifier with hard water
Hard water contains minerals that leave the water vapor as dust and will be distributed throughout the house
Describe atomizing humidification
It is based on the discharge of tiny water droplets into the air. The mist evaporates rapidly humidifying the air
What level of mold contamination corresponds to areas from 10 to 30 square feet?
Level 2
How does adding humidity to the air in a residence affect the thermostat setting
Raising the relative humidity of the air allows comfort levels at lower thermostat settings
Environmental tobacco smoke (ETS) is often referred to as ____________________.
Secondhand Smoke
How can humidification be provided in residences that do not have heating equipment with ductwork?
Self contained humidifiers may be installed
How would you check the calibration of a humidistat
Sling psychrometer
Define relative humidity
The percent of moisture in air as compared to the amount it could hold If it were saturated.
An atomizing humidifier should not operate when the furnace and blower are not operating. T/F
True
Caution must be used with changing from one air-cleaning filter type to another. If a technician replaces a low-density filter with a high-density filter it is very likely that the airflow will be reduced. T/F
True
The air in the home feels dry when it is heated because it expands, spreading out the moisture. T/F
True
A supplemental photocatalytic oxidation filter (PCO) is often included with ___ air purifiers
UV Ultraviolet
When odor is a concern, a filter containing ___ should be used
activated charcoal
The atomizing humidifiers can be spray nozzle or ___ types
centrifugal
One of the most common substances that is used as an absorber is ___.
charcoal
Because humidifiers use water, the evaporative surfaces and water reservoir must be cleaned and sanitized regularly to prevent the distributions of ____ by the moving airstream a. fungi b. bacteria c. algae d. all of the above
d. all of the above
Electronic air cleaners generally have ___. a. ionizing sections b. charcoal filters c. pre-filters d. all of the above
d. all of the above
The steps to aggressively controlling the contamination of indoor air would involve ____. a. locating and eliminating the source of contamination b. providing adequate ventilation c. providing methods for cleaning the air d. all of the above
d. all of the above
A house is built on property whose soil is rich in uranium. The occupants of the house may ___. a. be exposed to radon gas b. be more susceptible to lung cancer c. smell the pungent odor of the radon d. both a and b.
d. both a and b
A pleated filter __________. a. does not clog up as quickly as a standard filter b. is able to remove more dirt since the surface area is larger c. costs less than a standard filter d. both a and b.
d. both a and b
In the ionizing od an electronic air cleaner, the particles in the air are given a positive ___
electric charge
In electric furnace as well as heat pump systems, the recommended humidifier would be a(n) ___
electrically heated
Humidification generally relates to the process of causing water to ___ into the air.
evaporate
A fiberglass media air filter contains a dust-holding adhesive that helps prevent particulates from ____.
migrating downstream
The controller for a humidifier, a humidistat, has a power element that is ___ sensitive.
moisture
Atomizing humidifier discharge ___ into the air.
tiny water droplets
