Certified Energy Auditor Certification Building Envelope Assessment 3 — Questions and Answers
Question 1: Which ASTM standard governs the test method for air leakage of building envelopes using a blower door?
- ASTM E779 (Correct answer)
- ASTM C518
- ASTM E1186
- ASTM C1363
Correct answer: ASTM E779
ASTM E779 is the standard test method for determining air leakage rate by fan pressurization, which is the basis of blower door testing.
Question 2: What is the recommended pressure differential used during a standard blower door test?
- 10 Pa
- 25 Pa
- 50 Pa (Correct answer)
- 75 Pa
Correct answer: 50 Pa
The standard test pressure is 50 Pascals, and the resulting airflow (CFM50) is used to calculate ACH50 and ELA.
Question 3: Continuous insulation (ci) on the exterior of a wall primarily addresses which building science problem?
- Vapor diffusion through the sheathing
- Thermal bridging through studs (Correct answer)
- Air infiltration at window rough openings
- Moisture accumulation in batt insulation
Correct answer: Thermal bridging through studs
Exterior continuous insulation wraps over studs and other framing members, eliminating the thermal bridging pathway that degrades whole-wall R-value.
Question 4: Which building envelope component is typically responsible for the greatest share of infiltration in existing residential construction?
- Window glass
- Exterior wall penetrations and bypasses (Correct answer)
- Roof deck
- Foundation perimeter drain
Correct answer: Exterior wall penetrations and bypasses
Research consistently shows that penetrations, bypasses, and connections between assemblies (e.g., wall-to-ceiling, plumbing chases) account for the majority of unintended air leakage.
Question 5: When using infrared thermography to locate air leakage, what is the recommended minimum indoor-outdoor temperature difference?
- 5°F (3°C)
- 10°F (6°C)
- 15°F (8°C) (Correct answer)
- 25°F (14°C)
Correct answer: 15°F (8°C)
A minimum delta-T of approximately 15°F (8°C) is generally recommended to produce sufficient thermal contrast for reliable IRT results.
Question 6: A building's foundation wall transitions from below-grade to above-grade. Where should the auditor focus inspection for thermal bridging?
- At the footing drain tile
- At the sill plate and band joist area (Correct answer)
- At the interior vapor barrier lap
- At the exterior grading slope
Correct answer: At the sill plate and band joist area
The sill plate and band joist are often uninsulated or poorly insulated and represent a major thermal bridge and air leakage path at the foundation-to-wall transition.
Question 7: What does effective leakage area (ELA) measure in the context of envelope air tightness?
- Total window-to-wall ratio
- Equivalent hole size that would produce the measured leakage at a reference pressure (Correct answer)
- Percentage of duct leakage to outside
- Net-free area of attic ventilation
Correct answer: Equivalent hole size that would produce the measured leakage at a reference pressure
ELA expresses building air leakage as the size of a single sharp-edged orifice (at 4 Pa reference pressure) that would produce the same airflow as all the building's leaks combined.
Certified Energy Auditor Certification Building Envelope Assessment 3
Which ASTM standard governs the test method for air leakage of building envelopes using a blower door?