IICRC WRT FINAL EXAM STUDY GUIDE
QUESTIONS AND ANSWERS 2026/2027
1. According to the ANSI/IICRC S500, which category of water contains significant
contamination and has the potential to cause substantial discomfort or sickness if consumed
or touched?
A. Category 1
B. Category 2
C. Category 3
D. Category 4
Answer: B
Conceptual Explanation: Category 2 water contains significant contamination (e.g.,
discharge from dishwashers or washing machines). Category 3 is grossly unsanitary.
2. Which class of water loss involves the greatest volume of water and involves materials
with low permeance, such as hardwood or concrete?
A. Class 1
B. Class 2
,C. Class 4
D. Class 3
Answer: C
Conceptual Explanation: Class 4 involves specialty drying situations with deeply held or
bound moisture in materials like hardwood, brick, or stone.
3. What is the weight of water vapor in air, measured in grains per pound (gpp) of dry air?
A. Relative Humidity
B. Vapor Pressure
C. Dew Point
D. Humidity Ratio
Answer: D
Conceptual Explanation: Humidity Ratio (Specific Humidity) is the weight of water vapor
in the air, typically expressed in Grains Per Pound (GPP).
4. At what point does the air become saturated and water vapor begins to condense into
liquid water?
A. Equilibrium Moisture Content
B. Dry Bulb Temperature
C. Saturation Vapor Pressure
, D. Dew Point
Answer: D
Conceptual Explanation: The dew point is the temperature at which air is saturated
(100% RH) and condensation begins.
5. Which type of dehumidifier is most effective in environments with temperatures below
70°F and can achieve the lowest vapor pressure?
A. Conventional Refrigerant
B. Low Grain Refrigerant (LGR)
C. Thermoelectric
D. Desiccant
Answer: D
Conceptual Explanation: Desiccant dehumidifiers use chemicals to attract water and are
most effective in low temperatures and low humidity environments.
6. The process of water moving from a liquid state to a vapor state is known as:
A. Condensation
B. Evaporation
C. Sublimation
D. Transpiration
QUESTIONS AND ANSWERS 2026/2027
1. According to the ANSI/IICRC S500, which category of water contains significant
contamination and has the potential to cause substantial discomfort or sickness if consumed
or touched?
A. Category 1
B. Category 2
C. Category 3
D. Category 4
Answer: B
Conceptual Explanation: Category 2 water contains significant contamination (e.g.,
discharge from dishwashers or washing machines). Category 3 is grossly unsanitary.
2. Which class of water loss involves the greatest volume of water and involves materials
with low permeance, such as hardwood or concrete?
A. Class 1
B. Class 2
,C. Class 4
D. Class 3
Answer: C
Conceptual Explanation: Class 4 involves specialty drying situations with deeply held or
bound moisture in materials like hardwood, brick, or stone.
3. What is the weight of water vapor in air, measured in grains per pound (gpp) of dry air?
A. Relative Humidity
B. Vapor Pressure
C. Dew Point
D. Humidity Ratio
Answer: D
Conceptual Explanation: Humidity Ratio (Specific Humidity) is the weight of water vapor
in the air, typically expressed in Grains Per Pound (GPP).
4. At what point does the air become saturated and water vapor begins to condense into
liquid water?
A. Equilibrium Moisture Content
B. Dry Bulb Temperature
C. Saturation Vapor Pressure
, D. Dew Point
Answer: D
Conceptual Explanation: The dew point is the temperature at which air is saturated
(100% RH) and condensation begins.
5. Which type of dehumidifier is most effective in environments with temperatures below
70°F and can achieve the lowest vapor pressure?
A. Conventional Refrigerant
B. Low Grain Refrigerant (LGR)
C. Thermoelectric
D. Desiccant
Answer: D
Conceptual Explanation: Desiccant dehumidifiers use chemicals to attract water and are
most effective in low temperatures and low humidity environments.
6. The process of water moving from a liquid state to a vapor state is known as:
A. Condensation
B. Evaporation
C. Sublimation
D. Transpiration
