CMA Moisture & Building Science Flashcards

What does the term 'Equilibrium Moisture Content' (EMC) mean in the context of building materials?

Answer: The moisture level at which a material neither gains nor loses moisture to the surrounding air

EMC is the point at which a hygroscopic material's moisture content is in balance with the relative humidity of the surrounding environment.

Which psychrometric property represents the total heat content (sensible + latent) of moist air?

Answer: Enthalpy

Enthalpy (measured in BTU/lb or kJ/kg) represents the total heat energy in moist air including both sensible heat and latent heat of water vapor.

In a hot-humid climate like Florida, where should the vapor retarder be placed in a wall assembly?

Answer: On the exterior (warm-in-summer) side

In hot-humid climates, the dominant moisture drive is inward (from hot, humid exterior), so the retarder belongs on the exterior side.

What is the term for water moving upward through concrete or masonry due to capillary action?

Answer: Rising damp

Rising damp describes the upward migration of ground moisture through porous masonry or concrete via capillary action.

Which window condition is a reliable indicator of high indoor relative humidity and potential mold risk?

Answer: Condensation on interior pane in winter

Condensation forming on the interior surface of windows in winter indicates indoor relative humidity is high enough that the glass surface has reached dew point.

What does a high WUFI (Wärme- und Feuchtetransport) simulation result indicating 'mold growth potential' primarily depend on?

Answer: Temperature and relative humidity at the material surface over time

WUFI is hygrothermal simulation software that calculates mold risk based on the surface temperature and relative humidity history of building assemblies.