Applied Structural Drying
Technician
Final Test Review
(Questions & Solutions)
2025
1
,1. A flooded kitchen exhibits an ambient dry-bulb of 75 °F and 50 %
RH. Using a psychrometric chart, what is the approximate humidity
ratio (grains per pound of dry air)?
A. 50 gpp
B. 60 gpp
C. 70 gpp
D. 80 gpp
ANS: C
Rationale: At 75 °F and 50 % RH, psychrometric charts show a
humidity ratio near 70 gpp. Lower RH or temperature reduces the
ratio; higher increases it.
2. During monitoring, a restorer measures a surface temperature of
85 °F and determines the dew point is 60 °F. Which vapor pressure
differential (VPD) strategy maximizes evaporation?
A. Maintain surface 2 °F above dew point
B. Maintain surface 10 °F above dew point
C. Maintain surface 25 °F above dew point
D. Match surface to dew point
ANS: C
Rationale: Greater temperature difference increases VPD. A 25 °F
difference (85 °F–60 °F) drives faster evaporation than smaller
differentials.
3. A content drying chamber shows 72 °F dry-bulb and a dew point of
55 °F. Which type of dehumidifier will most efficiently lower RH in this
range?
A. Conventional refrigerant
B. Low-grain refrigerant (LGR)
C. Solid-desiccant
2
, D. Portable condenser
ANS: B
Rationale: LGR units are optimized around 70–80 °F and moderate
RH, removing more moisture pints per day at lower RH than
conventional refrigerant types.
4. A restorer defines a “dry standard” for gypsum board at 12 % MC
based on unaffected readings. Which equilibrium relative humidity
(ERH) corresponds to this target?
A. 50 % ERH
B. 65 % ERH
C. 75 % ERH
D. 85 % ERH
ANS: C
Rationale: Gypsum board at ~12 % MC typically equilibrates at ~75 %
ERH. This helps set drying goals by matching unaffected materials.
5. In a closed-drying environment, why is balanced drying
(evaporation rate ≈ dehumidification rate) critical?
A. Prevents over-drying materials
B. Avoids condensation on cold surfaces
C. Minimizes energy consumption
D. All of the above
ANS: D
Rationale: Balanced drying maintains stable conditions, prevents
secondary moisture migration or condensation, and optimizes energy
use.
6. After 24 hours of drying, moisture readings on hardwood floor drop
by only 2 %. What psychrometric change most likely accelerates
drying?
A. Increase dry-bulb to 80 °F
3
Technician
Final Test Review
(Questions & Solutions)
2025
1
,1. A flooded kitchen exhibits an ambient dry-bulb of 75 °F and 50 %
RH. Using a psychrometric chart, what is the approximate humidity
ratio (grains per pound of dry air)?
A. 50 gpp
B. 60 gpp
C. 70 gpp
D. 80 gpp
ANS: C
Rationale: At 75 °F and 50 % RH, psychrometric charts show a
humidity ratio near 70 gpp. Lower RH or temperature reduces the
ratio; higher increases it.
2. During monitoring, a restorer measures a surface temperature of
85 °F and determines the dew point is 60 °F. Which vapor pressure
differential (VPD) strategy maximizes evaporation?
A. Maintain surface 2 °F above dew point
B. Maintain surface 10 °F above dew point
C. Maintain surface 25 °F above dew point
D. Match surface to dew point
ANS: C
Rationale: Greater temperature difference increases VPD. A 25 °F
difference (85 °F–60 °F) drives faster evaporation than smaller
differentials.
3. A content drying chamber shows 72 °F dry-bulb and a dew point of
55 °F. Which type of dehumidifier will most efficiently lower RH in this
range?
A. Conventional refrigerant
B. Low-grain refrigerant (LGR)
C. Solid-desiccant
2
, D. Portable condenser
ANS: B
Rationale: LGR units are optimized around 70–80 °F and moderate
RH, removing more moisture pints per day at lower RH than
conventional refrigerant types.
4. A restorer defines a “dry standard” for gypsum board at 12 % MC
based on unaffected readings. Which equilibrium relative humidity
(ERH) corresponds to this target?
A. 50 % ERH
B. 65 % ERH
C. 75 % ERH
D. 85 % ERH
ANS: C
Rationale: Gypsum board at ~12 % MC typically equilibrates at ~75 %
ERH. This helps set drying goals by matching unaffected materials.
5. In a closed-drying environment, why is balanced drying
(evaporation rate ≈ dehumidification rate) critical?
A. Prevents over-drying materials
B. Avoids condensation on cold surfaces
C. Minimizes energy consumption
D. All of the above
ANS: D
Rationale: Balanced drying maintains stable conditions, prevents
secondary moisture migration or condensation, and optimizes energy
use.
6. After 24 hours of drying, moisture readings on hardwood floor drop
by only 2 %. What psychrometric change most likely accelerates
drying?
A. Increase dry-bulb to 80 °F
3
