IICRC WATER RESTORATION TECHNICIAN (WRT) READINESS
EXAM | QUESTIONS AND ANSWERS | VERIFIED ANSWERS PLUS
RATIONALES | LATEST EXAM UPDATE
PRINCIPLES, PSYCHROMETRICS & SCIENCE
Classes & Categories (advanced traps)
Structural assembly drying
Equipment calculation & failure analysis
Microbial contamination decision-making
Containment, pressure, and engineering controls
Safety, OSHA, PPE, and jobsite risk
Documentation defensibility & expert-witness logic
Final-level scenario questions
PRINCIPLES, PSYCHROMETRICS & SCIENCE
1. What primarily drives evaporation from a wet material surface?
A. Air velocity alone
B. Temperature alone
C. Vapor pressure differential
D. Relative humidity alone
Answer: C. Vapor pressure differential
Rationale: Evaporation is driven by differences in vapor pressure between
material and air.
2. Which psychrometric change most increases grain depression?
A. Increasing RH
B. Decreasing dry bulb temperature
C. Lowering dew point
D. Increasing moisture content of air
,Answer: C. Lowering dew point
Rationale: Lower dew point increases the air’s moisture-holding capacity.
3. What does equilibrium moisture content (EMC) represent?
A. Maximum moisture a material can hold
B. Moisture at saturation
C. Moisture level matching ambient conditions
D. Zero moisture state
Answer: C. Moisture level matching ambient conditions
Rationale: EMC occurs when material and air reach balance.
4. Which condition reduces evaporation even with high airflow?
A. Low RH
B. High grain depression
C. Saturated ambient air
D. Elevated temperature
Answer: C. Saturated ambient air
Rationale: Moist air cannot accept additional vapor.
5. What happens when materials are dried below normal EMC?
A. Faster restoration
B. Structural strengthening
C. Shrinkage and cracking
D. Increased microbial risk
Answer: C. Shrinkage and cracking
Rationale: Over-drying damages materials.
6. Which parameter best confirms drying progress?
A. Elapsed time
B. Equipment count
C. Comparative moisture readings
D. Ambient temperature
,Answer: C. Comparative moisture readings
Rationale: Objective measurements confirm progress.
7. Which factor MOST affects diffusion drying?
A. Gravity
B. Vapor pressure
C. Capillary action
D. Air turbulence
Answer: B. Vapor pressure
Rationale: Diffusion depends on vapor pressure gradients.
8. Which statement about temperature is MOST accurate?
A. Higher temperature always improves drying
B. Heat alone dries materials
C. Heat increases vapor pressure
D. Heat reduces RH permanently
Answer: C. Heat increases vapor pressure
Rationale: Higher temperature increases evaporation potential.
9. What is the psychrometric definition of grains?
A. Weight of liquid water
B. Relative humidity scale
C. Mass of water vapor per pound of dry air
D. Condensation rate
Answer: C. Mass of water vapor per pound of dry air
Rationale: Grains quantify absolute moisture.
10. Why is RH alone unreliable for drying decisions?
A. It fluctuates constantly
B. It ignores temperature
C. It ignores airflow
D. It measures surface moisture
, Answer: B. It ignores temperature
Rationale: RH without temperature lacks context.
11. Which drying phase removes bound water?
A. Extraction
B. Constant rate
C. Falling rate
D. Migration
Answer: C. Falling rate
Rationale: Bound water removal occurs during falling rate.
12. What occurs if evaporation exceeds dehumidification?
A. Faster drying
B. Condensation risk
C. Lower RH
D. Stable grain depression
Answer: B. Condensation risk
Rationale: Moisture accumulates in the air.
13. Which material has the highest EMC?
A. Concrete
B. Hardwood
C. Gypsum board
D. Carpet fiber
Answer: A. Concrete
Rationale: Concrete stores large amounts of bound moisture.
14. What does “latent heat” refer to?
A. Sensible temperature change
B. Energy used to move air
C. Energy required to change water phase
D. Heat loss through walls
EXAM | QUESTIONS AND ANSWERS | VERIFIED ANSWERS PLUS
RATIONALES | LATEST EXAM UPDATE
PRINCIPLES, PSYCHROMETRICS & SCIENCE
Classes & Categories (advanced traps)
Structural assembly drying
Equipment calculation & failure analysis
Microbial contamination decision-making
Containment, pressure, and engineering controls
Safety, OSHA, PPE, and jobsite risk
Documentation defensibility & expert-witness logic
Final-level scenario questions
PRINCIPLES, PSYCHROMETRICS & SCIENCE
1. What primarily drives evaporation from a wet material surface?
A. Air velocity alone
B. Temperature alone
C. Vapor pressure differential
D. Relative humidity alone
Answer: C. Vapor pressure differential
Rationale: Evaporation is driven by differences in vapor pressure between
material and air.
2. Which psychrometric change most increases grain depression?
A. Increasing RH
B. Decreasing dry bulb temperature
C. Lowering dew point
D. Increasing moisture content of air
,Answer: C. Lowering dew point
Rationale: Lower dew point increases the air’s moisture-holding capacity.
3. What does equilibrium moisture content (EMC) represent?
A. Maximum moisture a material can hold
B. Moisture at saturation
C. Moisture level matching ambient conditions
D. Zero moisture state
Answer: C. Moisture level matching ambient conditions
Rationale: EMC occurs when material and air reach balance.
4. Which condition reduces evaporation even with high airflow?
A. Low RH
B. High grain depression
C. Saturated ambient air
D. Elevated temperature
Answer: C. Saturated ambient air
Rationale: Moist air cannot accept additional vapor.
5. What happens when materials are dried below normal EMC?
A. Faster restoration
B. Structural strengthening
C. Shrinkage and cracking
D. Increased microbial risk
Answer: C. Shrinkage and cracking
Rationale: Over-drying damages materials.
6. Which parameter best confirms drying progress?
A. Elapsed time
B. Equipment count
C. Comparative moisture readings
D. Ambient temperature
,Answer: C. Comparative moisture readings
Rationale: Objective measurements confirm progress.
7. Which factor MOST affects diffusion drying?
A. Gravity
B. Vapor pressure
C. Capillary action
D. Air turbulence
Answer: B. Vapor pressure
Rationale: Diffusion depends on vapor pressure gradients.
8. Which statement about temperature is MOST accurate?
A. Higher temperature always improves drying
B. Heat alone dries materials
C. Heat increases vapor pressure
D. Heat reduces RH permanently
Answer: C. Heat increases vapor pressure
Rationale: Higher temperature increases evaporation potential.
9. What is the psychrometric definition of grains?
A. Weight of liquid water
B. Relative humidity scale
C. Mass of water vapor per pound of dry air
D. Condensation rate
Answer: C. Mass of water vapor per pound of dry air
Rationale: Grains quantify absolute moisture.
10. Why is RH alone unreliable for drying decisions?
A. It fluctuates constantly
B. It ignores temperature
C. It ignores airflow
D. It measures surface moisture
, Answer: B. It ignores temperature
Rationale: RH without temperature lacks context.
11. Which drying phase removes bound water?
A. Extraction
B. Constant rate
C. Falling rate
D. Migration
Answer: C. Falling rate
Rationale: Bound water removal occurs during falling rate.
12. What occurs if evaporation exceeds dehumidification?
A. Faster drying
B. Condensation risk
C. Lower RH
D. Stable grain depression
Answer: B. Condensation risk
Rationale: Moisture accumulates in the air.
13. Which material has the highest EMC?
A. Concrete
B. Hardwood
C. Gypsum board
D. Carpet fiber
Answer: A. Concrete
Rationale: Concrete stores large amounts of bound moisture.
14. What does “latent heat” refer to?
A. Sensible temperature change
B. Energy used to move air
C. Energy required to change water phase
D. Heat loss through walls
