IICRC WRT 2026/2027 PROFESSIONAL
EXAM PREP QUESTIONS AND
ANSWERS
1. According to the IICRC S500, which factor is the primary driver of evaporation from a wet
surface?
A. Vapor pressure differential between the surface and the air
B. High relative humidity in the ambient air
C. The total volume of air in the affected space
D. The specific gravity of the liquid water
Answer: A
Conceptual Explanation: Evaporation occurs when the vapor pressure of the moisture in
the material is higher than the vapor pressure of the air. The greater the differential, the
faster the evaporation.
2. When water contains significant contamination and has the potential to cause discomfort
or sickness if consumed, it is classified as:
A. Category 1
,B. Special Regulated Category
C. Category 3
D. Category 2
Answer: D
Conceptual Explanation: Category 2 water contains significant contamination (e.g.,
dishwasher discharge, aquarium leaks) and has the potential to cause discomfort or
sickness.
3. In a Class 4 water intrusion, which of the following is true?
A. It involves only low-porosity materials like concrete or hardwood.
B. Water has affected less than 5% of the total surface area.
C. Evaporation is easily achieved with standard air movers alone.
D. Deeply held or bound water is present in low-evaporation materials.
Answer: D
Conceptual Explanation: Class 4 involves specialty drying situations where moisture is
trapped in low-evaporation materials like hardwood, plaster, or concrete, requiring specific
drying methods.
4. What is the ‘Fiber Saturation Point’ (FSP) in wood, and why is it significant in restoration?
A. The point at which wood begins to rot, typically 20% MC.
B. The moisture level where wood starts to expand visibly.
, C. The point (approx. 30% MC) where all cell cavities are empty but cell walls are saturated.
D. The maximum moisture content wood can hold, usually 100%.
Answer: C
Conceptual Explanation: The Fiber Saturation Point is roughly 30% moisture content.
Above this, water is ‘free’ in cell cavities; below this, water is ‘bound’ in cell walls, which
affects dimensional stability.
5. Which psychrometric property is defined as the weight of water vapor in the air per pound
of dry air?
A. Relative Humidity
B. Dew Point
C. Vapor Pressure
D. Humidity Ratio (Grains Per Pound)
Answer: D
Conceptual Explanation: Humidity Ratio, expressed in Grains Per Pound (GPP), measures
the weight of water vapor relative to the weight of dry air.
6. If the temperature of a room increases while the absolute moisture content (GPP) remains
constant, what happens to the Relative Humidity (RH)?
A. RH decreases
B. RH increases
EXAM PREP QUESTIONS AND
ANSWERS
1. According to the IICRC S500, which factor is the primary driver of evaporation from a wet
surface?
A. Vapor pressure differential between the surface and the air
B. High relative humidity in the ambient air
C. The total volume of air in the affected space
D. The specific gravity of the liquid water
Answer: A
Conceptual Explanation: Evaporation occurs when the vapor pressure of the moisture in
the material is higher than the vapor pressure of the air. The greater the differential, the
faster the evaporation.
2. When water contains significant contamination and has the potential to cause discomfort
or sickness if consumed, it is classified as:
A. Category 1
,B. Special Regulated Category
C. Category 3
D. Category 2
Answer: D
Conceptual Explanation: Category 2 water contains significant contamination (e.g.,
dishwasher discharge, aquarium leaks) and has the potential to cause discomfort or
sickness.
3. In a Class 4 water intrusion, which of the following is true?
A. It involves only low-porosity materials like concrete or hardwood.
B. Water has affected less than 5% of the total surface area.
C. Evaporation is easily achieved with standard air movers alone.
D. Deeply held or bound water is present in low-evaporation materials.
Answer: D
Conceptual Explanation: Class 4 involves specialty drying situations where moisture is
trapped in low-evaporation materials like hardwood, plaster, or concrete, requiring specific
drying methods.
4. What is the ‘Fiber Saturation Point’ (FSP) in wood, and why is it significant in restoration?
A. The point at which wood begins to rot, typically 20% MC.
B. The moisture level where wood starts to expand visibly.
, C. The point (approx. 30% MC) where all cell cavities are empty but cell walls are saturated.
D. The maximum moisture content wood can hold, usually 100%.
Answer: C
Conceptual Explanation: The Fiber Saturation Point is roughly 30% moisture content.
Above this, water is ‘free’ in cell cavities; below this, water is ‘bound’ in cell walls, which
affects dimensional stability.
5. Which psychrometric property is defined as the weight of water vapor in the air per pound
of dry air?
A. Relative Humidity
B. Dew Point
C. Vapor Pressure
D. Humidity Ratio (Grains Per Pound)
Answer: D
Conceptual Explanation: Humidity Ratio, expressed in Grains Per Pound (GPP), measures
the weight of water vapor relative to the weight of dry air.
6. If the temperature of a room increases while the absolute moisture content (GPP) remains
constant, what happens to the Relative Humidity (RH)?
A. RH decreases
B. RH increases
