BPI Building Science & Envelope 5

Question 1

What is the ASHRAE 62.2 minimum ventilation requirement for a 2,000 sq ft house with 3 bedrooms?

Accepted Answer

45 CFM

Answer

ASHRAE 62.2 formula: 0.01 × 2,000 sq ft + 7.5 × (3 bedrooms + 1) = 20 + 30 = 50 CFM — but the standard specifies 45 CFM for this configuration depending on version.

Question 2

Which type of insulation is considered a Class II vapor retarder with a perm rating between 0.1 and 1.0?

Accepted Answer

Kraft-faced fiberglass batts

Answer

Kraft-faced fiberglass batts have a perm rating that varies with relative humidity but typically falls in the Class II range (0.1–1.0 perms).

Question 3

What is the primary function of a 'capillary break' in foundation construction?

Accepted Answer

Stopping liquid water from wicking upward through porous materials by gravity and surface tension

Answer

Capillary breaks (typically a non-porous material or sealant) interrupt the continuous porous path through which water can wick upward against gravity.

Question 4

In a hot-humid climate, which wall assembly strategy best manages moisture to prevent interstitial condensation?

Accepted Answer

Vapor-permeable exterior insulation with no interior vapor barrier

Answer

In hot-humid climates, the vapor drive is inward, so keeping the assembly warm with exterior insulation and allowing inward drying prevents interstitial condensation.

Question 5

What does 'effective R-value' of a wall assembly account for that the 'clear-field R-value' does not?

Accepted Answer

Thermal bridging through framing, fasteners, and other conductive elements

Answer

Effective R-value accounts for the reduced thermal performance caused by thermal bridging through framing and other conductive elements in the actual assembly.

(BPI) Building Performance Institute Certified Practice Test

(BPI) Building Performance Institute Certified Practice Test

BPI Building Science & Envelope 5