HERS Building Science Principles 3

Question 1

How does wind-driven rain most commonly enter a wall assembly in a climate with high wind exposure?

Accepted Answer

Forced water entry through gaps and cracks under pressure

Answer

Wind pressure forces liquid water through gaps, cracks, and penetrations in the cladding and air barrier under positive pressure.

Question 2

What is 'interstitial condensation' in a building assembly?

Accepted Answer

Condensation forming within the layers of a wall, roof, or floor assembly

Answer

Interstitial condensation occurs inside the building assembly layers when vapor migrates to a surface that is at or below the dew point.

Question 3

A building with tight construction and mechanical ventilation exemplifies which principle from ASHRAE 62.2?

Accepted Answer

Build tight, ventilate right

Answer

ASHRAE 62.2 embraces the 'build tight, ventilate right' approach, using controlled mechanical ventilation instead of uncontrolled air leakage.

Question 4

Which type of foundation is most susceptible to ground moisture intrusion by capillary action?

Accepted Answer

Slab-on-grade without capillary break

Answer

Concrete slabs placed directly on soil without a capillary break (gravel layer or poly film) allow moisture to wick upward continuously.

Question 5

In whole-building energy modeling, what does the term 'internal gains' refer to?

Accepted Answer

Heat generated inside the building by occupants, lighting, and appliances

Answer

Internal gains are heat sources within the conditioned space—occupants, lights, cooking, and plug loads—that contribute to the cooling load.

(HERS) Certified Home Energy Rating System Rater Practice Test