Flood Restoration Psychrometrics and Humidity Control 2

Question 1

Which type of dehumidifier performs best in low-temperature environments below 50°F?

Accepted Answer

Desiccant dehumidifier

Answer

Refrigerant (mechanical) dehumidifier

Answer

Thermoelectric dehumidifier

Answer

Evaporative cooler

Question 2

Vapor pressure differential in the context of structural drying refers to:

Accepted Answer

The difference in moisture vapor pressure between wet building materials and the surrounding air

Answer

The difference in barometric pressure inside versus outside a structure

Answer

The pressure difference created by operating multiple air movers simultaneously

Answer

The humidity gap between floor level and ceiling level of a structure

Question 3

In psychrometrics, 'humidity ratio' (specific humidity) is expressed as:

Accepted Answer

Pounds of water vapor per pound of dry air

Answer

Percentage of saturation at a given temperature

Answer

Grains of moisture per cubic foot of air

Answer

Millimeters of mercury of vapor pressure

Question 4

During the evaporation phase of structural drying, what happens to the relative humidity of the air in the drying space?

Accepted Answer

It increases as water evaporates from wet surfaces into the air

Answer

It decreases as moisture is drawn back into wet materials

Answer

It stays stable if equipment is balanced correctly

Answer

It drops immediately when air movers are first activated

Question 5

The primary function of air movers (axial fans) in a structural drying system is to:

Accepted Answer

Create high-velocity airflow across wet surfaces to accelerate evaporation

Answer

Lower the temperature of the affected area to inhibit mold growth

Answer

Filter airborne contaminants and allergens released from flood-damaged materials

Answer

Distribute dehumidified air evenly throughout the entire structure

Question 6

Desiccant dehumidifiers have an advantage over refrigerant units specifically when:

Accepted Answer

Temperatures are very low or extremely low humidity levels must be achieved

Answer

Temperatures are high (above 90°F) and relative humidity is very high

Answer

The RH has already been reduced below 40% at normal room temperature

Answer

Processing large volumes of standing water during the initial extraction phase

Question 7

The IICRC S500 standard reference drying conditions used as a psychrometric baseline are approximately:

Accepted Answer

70°F and 50% RH

Answer

75°F and 55% RH

Answer

80°F and 40% RH

Answer

65°F and 60% RH