IICRC WRT FINAL EXAM ADVANCED
PREPARATION 2026/2027 QUESTIONS
AND ANSWERS
1. According to the IICRC S500, which category of water contains significant contamination
and has the potential to cause discomfort or sickness if consumed by or exposed to humans?
A. Category 1
B. Special Category
C. Category 3
D. Category 2
Answer: D
Conceptual Explanation: Category 2 water contains significant contamination (e.g.,
discharge from dishwashers or washing machines). Category 3 is grossly unsanitary, and
Category 1 is clean.
,2. Which drying class involves a large amount of water, where the materials are highly porous
(e.g., carpet, pad, gypsum board) and represent more than ~20% but less than ~40% of the
combined floor, wall, and ceiling surface area?
A. Class 1
B. Class 2
C. Class 3
D. Class 4
Answer: B
Conceptual Explanation: Class 2 involves a significant amount of water affecting more
than 20% but less than 40% of the total surface area of the room.
3. At what temperature does the LGR (Low Grain Refrigerant) dehumidifier generally begin to
lose its efficiency compared to conventional refrigerants?
A. Above 90°F (32°C)
B. Above 105°F (41°C)
C. Below 70°F (21°C)
D. Below 32°F (0°C)
Answer: B
, Conceptual Explanation: LGR dehumidifiers are designed to work in lower humidity, but
standard refrigerant cycles lose efficiency above 100-105°F due to the difficulty of
condensing refrigerant.
4. If the ambient air temperature is 80°F and the Relative Humidity is 60%, what is the
approximate Grains Per Pound (GPP)?
A. 130 GPP
B. 110 GPP
C. 65 GPP
D. 92 GPP
Answer: D
Conceptual Explanation: Using a psychrometric chart, 80°F at 60% RH yields
approximately 92 grains per pound of dry air.
5. What is the pressure exerted by the molecules of water vapor in the air against a surface
called?
A. Atmospheric Pressure
B. Surface Tension
C. Vapor Pressure
D. Osmotic Pressure
Answer: C
PREPARATION 2026/2027 QUESTIONS
AND ANSWERS
1. According to the IICRC S500, which category of water contains significant contamination
and has the potential to cause discomfort or sickness if consumed by or exposed to humans?
A. Category 1
B. Special Category
C. Category 3
D. Category 2
Answer: D
Conceptual Explanation: Category 2 water contains significant contamination (e.g.,
discharge from dishwashers or washing machines). Category 3 is grossly unsanitary, and
Category 1 is clean.
,2. Which drying class involves a large amount of water, where the materials are highly porous
(e.g., carpet, pad, gypsum board) and represent more than ~20% but less than ~40% of the
combined floor, wall, and ceiling surface area?
A. Class 1
B. Class 2
C. Class 3
D. Class 4
Answer: B
Conceptual Explanation: Class 2 involves a significant amount of water affecting more
than 20% but less than 40% of the total surface area of the room.
3. At what temperature does the LGR (Low Grain Refrigerant) dehumidifier generally begin to
lose its efficiency compared to conventional refrigerants?
A. Above 90°F (32°C)
B. Above 105°F (41°C)
C. Below 70°F (21°C)
D. Below 32°F (0°C)
Answer: B
, Conceptual Explanation: LGR dehumidifiers are designed to work in lower humidity, but
standard refrigerant cycles lose efficiency above 100-105°F due to the difficulty of
condensing refrigerant.
4. If the ambient air temperature is 80°F and the Relative Humidity is 60%, what is the
approximate Grains Per Pound (GPP)?
A. 130 GPP
B. 110 GPP
C. 65 GPP
D. 92 GPP
Answer: D
Conceptual Explanation: Using a psychrometric chart, 80°F at 60% RH yields
approximately 92 grains per pound of dry air.
5. What is the pressure exerted by the molecules of water vapor in the air against a surface
called?
A. Atmospheric Pressure
B. Surface Tension
C. Vapor Pressure
D. Osmotic Pressure
Answer: C
