IICRC WRT - Institute of Inspection, Cleaning and Restoration Certification Water Damage Restoration Technician Psychrometry and Drying Principles Questions and Answers

Question 1

A water restoration technician arrives at a job site and measures the air conditions in the affected room to be 75°F and 70% relative humidity.
Using a psychrometric chart, they determine the specific humidity is 92 grains per pound (GPP).
To create an effective drying environment, the technician's primary psychrometric goal should be to:

Accepted Answer

Decrease the relative humidity and the GPP of the air.

Answer

Increase the temperature to increase the GPP.

Answer

Maintain the current conditions as they are optimal for evaporation.

Answer

Increase the relative humidity to match the GPP.

Question 2

Which of the following psychrometric measurements provides a direct indication of the actual weight of water vapor contained in a pound of air, regardless of the air's temperature?

Accepted Answer

Grains Per Pound (GPP)

Answer

Relative Humidity (RH)

Answer

Dew Point Temperature

Answer

Wet-Bulb Temperature

Question 3

A technician is drying a structure with a high vapor pressure differential between the wet materials and the surrounding air. What is the most likely outcome of this condition?

Accepted Answer

The drying process will be accelerated.

Answer

The rate of evaporation will slow down significantly.

Answer

Condensation will begin to form on cooler surfaces.

Answer

The risk of secondary damage from mold will increase.

Question 4

On a cold winter day, a restorer is attempting to dry a water-damaged room. They notice that their standard refrigerant dehumidifiers are not removing much water. The most likely reason for this is that the cold air:

Accepted Answer

has a low moisture-holding capacity, reducing dehumidifier efficiency.

Answer

has a naturally high vapor pressure.

Answer

is too dense for the dehumidifier to process.

Answer

causes the GPP to be artificially high.

Question 5

A technician is monitoring a dehumidifier's performance. They measure the Grains Per Pound (GPP) of the air entering the machine and the GPP of the air leaving it. This calculation is used to determine the:

Accepted Answer

Grain Depression

Answer

Dew Point Depression

Answer

Relative Humidity Efficiency

Answer

Vapor Pressure Gradient

Question 6

What is the dew point temperature?

Accepted Answer

The temperature at which the air becomes saturated and water vapor condenses into a liquid.

Answer

The temperature at which a material begins to absorb moisture from the air.

Answer

The temperature at which water evaporates most efficiently.

Answer

The average temperature of the air and a wet surface.