IICRC WRT 2026/2027 ADVANCED
CERTIFICATION PREP
1. According to the IICRC S500, what is the primary purpose of applying a professional biocide
in a Category 2 water intrusion?
A. To inhibit microbial growth and cross-contamination
B. To clean the surface of debris
C. To increase the rate of evaporation
D. To neutralize alkaline salts in the carpet
Answer: A
Conceptual Explanation: Biocides are used specifically to control or kill microorganisms
to prevent health risks and further degradation during the drying process.
2. Which psychrometric term describes the actual weight of water vapor in the air, measured
in grains per pound (gpp)?
A. Humidity Ratio
B. Dew Point
C. Relative Humidity
,D. Vapor Pressure
Answer: A
Conceptual Explanation: Humidity ratio, often expressed as grains per pound (gpp),
represents the weight of water vapor per unit weight of dry air.
3. In a drying environment, if the temperature increases while the humidity ratio (gpp)
remains constant, what happens to the relative humidity?
A. It decreases
B. It increases
C. It remains the same
D. It fluctuates unpredictably
Answer: A
Conceptual Explanation: Relative humidity is inversely proportional to temperature
when the moisture content (gpp) is constant; warmer air can hold more moisture, thus RH
drops.
4. Which water category is characterized by water that contains significant contamination
and has the potential to cause sickness if consumed?
A. Category 2
B. Category 1
C. Category 3
, D. Category 4
Answer: A
Conceptual Explanation: Category 2 water (formerly ‘gray water’) contains significant
contamination and has potential for discomfort or sickness.
5. What is the specific definition of a Class 4 water intrusion?
A. Water affecting only part of a room with low-evaporation materials
B. Water affecting the entire room, including walls and ceilings
C. Deeply held or bound water in low-evaporation materials like hardwood or concrete
D. Water originating from a clean source like a supply line
Answer: C
Conceptual Explanation: Class 4 involves specialty drying situations with deeply
saturated materials requiring low vapor pressure environments.
6. What is the most effective method for removing the bulk of water from a carpet and pad?
A. Sub-surface extraction
B. LGR dehumidification
C. High-volume air movers
D. Increasing the ambient temperature
Answer: A
CERTIFICATION PREP
1. According to the IICRC S500, what is the primary purpose of applying a professional biocide
in a Category 2 water intrusion?
A. To inhibit microbial growth and cross-contamination
B. To clean the surface of debris
C. To increase the rate of evaporation
D. To neutralize alkaline salts in the carpet
Answer: A
Conceptual Explanation: Biocides are used specifically to control or kill microorganisms
to prevent health risks and further degradation during the drying process.
2. Which psychrometric term describes the actual weight of water vapor in the air, measured
in grains per pound (gpp)?
A. Humidity Ratio
B. Dew Point
C. Relative Humidity
,D. Vapor Pressure
Answer: A
Conceptual Explanation: Humidity ratio, often expressed as grains per pound (gpp),
represents the weight of water vapor per unit weight of dry air.
3. In a drying environment, if the temperature increases while the humidity ratio (gpp)
remains constant, what happens to the relative humidity?
A. It decreases
B. It increases
C. It remains the same
D. It fluctuates unpredictably
Answer: A
Conceptual Explanation: Relative humidity is inversely proportional to temperature
when the moisture content (gpp) is constant; warmer air can hold more moisture, thus RH
drops.
4. Which water category is characterized by water that contains significant contamination
and has the potential to cause sickness if consumed?
A. Category 2
B. Category 1
C. Category 3
, D. Category 4
Answer: A
Conceptual Explanation: Category 2 water (formerly ‘gray water’) contains significant
contamination and has potential for discomfort or sickness.
5. What is the specific definition of a Class 4 water intrusion?
A. Water affecting only part of a room with low-evaporation materials
B. Water affecting the entire room, including walls and ceilings
C. Deeply held or bound water in low-evaporation materials like hardwood or concrete
D. Water originating from a clean source like a supply line
Answer: C
Conceptual Explanation: Class 4 involves specialty drying situations with deeply
saturated materials requiring low vapor pressure environments.
6. What is the most effective method for removing the bulk of water from a carpet and pad?
A. Sub-surface extraction
B. LGR dehumidification
C. High-volume air movers
D. Increasing the ambient temperature
Answer: A
