Psychrometrics & Structural Drying Principles Flashcards

What does psychrometrics refer to in the context of restoration?

Answer: The science of measuring and controlling air-moisture properties

Psychrometrics is the science that studies the properties of air-water vapor mixtures, which is foundational to structural drying in restoration.

How is relative humidity (RH) best defined?

Answer: The ratio of actual water vapor in air to the maximum possible at that temperature, expressed as a percentage

Relative humidity expresses actual moisture content as a percentage of the maximum moisture air can hold at a given temperature.

What is the dew point temperature?

Answer: The temperature at which air becomes saturated and condensation begins to form

The dew point is the temperature at which air must be cooled, at constant pressure, to reach saturation and begin condensing moisture onto surfaces.

In psychrometrics, what is a 'grain' of moisture?

Answer: A standard unit of moisture equal to 1/7,000 of a pound

A grain is a unit of weight for water; there are 7,000 grains per pound, used to express airborne moisture content in grains per pound (GPP) of dry air.

What does the abbreviation GPP stand for in structural drying?

Answer: Grains Per Pound of dry air

GPP (Grains Per Pound) measures the actual water vapor content of air by weight and is used to assess how much moisture the air is carrying at any given time.

How is wet bulb temperature measured?

Answer: By reading a thermometer whose bulb is wrapped in a moistened wick exposed to moving air

Wet bulb temperature is measured with a thermometer wrapped in a wet wick; evaporative cooling from the wick lowers the reading, indicating the air's moisture content.

Which standard provides the primary psychrometric and structural drying guidance used by restoration professionals?

Answer: IICRC S500 Standard for Professional Water Damage Restoration

The IICRC S500 is the principal standard governing water damage restoration, including the psychrometric principles that guide structural drying decisions.