Psychrometrics and Humidity Control Flashcards
7 cards from real Flood Restoration practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Psychrometrics and Humidity Control flashcards as text
How does increasing indoor temperature during structural drying affect the evaporation rate?
Answer: It accelerates evaporation by increasing the vapor pressure differential between wet materials and the air
Higher temperatures increase the vapor pressure at wet material surfaces relative to the air, widening the differential that drives moisture to migrate outward and evaporate.
'Grain depression' in dehumidifier performance measurement refers to:
Answer: The difference in grains per pound (GPP) between air entering and air leaving the dehumidifier
Grain depression measures how many grains of moisture per pound of air the dehumidifier actually removes, serving as a key indicator of real-world performance.
Which combination of conditions would MOST impede the drying of a flood-damaged structure?
Answer: Low temperature and high relative humidity
Cold air holds less moisture and high relative humidity means the air has little remaining capacity to accept evaporating moisture, both severely slowing the drying process.
In the IICRC S500 standard, 'Class of Water Damage' classification is determined by:
Answer: The potential evaporation load — the amount of moisture absorbed into materials that must be removed
Water Damage Classes 1 through 4 reflect how much moisture has been absorbed into building materials and contents, which determines the drying equipment capacity required.
When using psychrometric data to evaluate whether structural drying is progressing, technicians primarily monitor:
Answer: The reduction in grains per pound (GPP) of moisture in the air
Tracking GPP reduction over daily readings shows whether the combined air mover and dehumidifier system is successfully removing moisture from the drying assembly.
Secondary wetting or condensation damage during flood restoration most commonly occurs when:
Answer: Warm, moisture-laden air contacts cool surfaces below the dew point, causing condensation
When warm, humid air in the drying space contacts a cold surface such as an exterior wall or window below the dew point, moisture condenses there and creates additional water damage.
A refrigerant dehumidifier operates at peak efficiency when:
Answer: Indoor temperatures are between 70–90°F and relative humidity is above 45%
Refrigerant dehumidifiers are designed for warm, humid conditions; below about 65°F, the refrigerant coils can ice over and shut down moisture removal.