BAP Weatherization & Retrofit Measures Flashcards

What does 'ACH50' measure in the context of building performance testing?

Answer: The number of times the building's air volume is exchanged per hour at 50 Pascals of pressure

ACH50 (air changes per hour at 50 Pascals) normalizes blower door CFM50 by the building volume, allowing comparison of airtightness across differently sized homes.

After tightening a home's envelope, what must a BAP analyst verify to maintain indoor air quality?

Answer: That mechanical ventilation is adequate per ASHRAE 62.2 or equivalent standard

Tightening the envelope reduces natural infiltration, so mechanical ventilation must be verified or added to maintain acceptable indoor air quality per ASHRAE 62.2.

What is the purpose of a 'house-to-outside' duct leakage test (Qn,out)?

Answer: To quantify only the duct leakage that goes to unconditioned spaces outside the thermal envelope

Duct leakage to outside (Qn,out) measures only the leakage from ducts into unconditioned spaces like attics or crawlspaces — the leakage that directly wastes conditioned air.

In a hot-humid climate (US Climate Zone 2), where should the vapor retarder generally be located in a wall assembly?

Answer: Vapor retarders are not recommended in hot-humid climates

In hot-humid climates, interior vapor barriers trap moisture driven inward by cooling systems, so most building codes and energy programs avoid interior vapor retarders in these zones.

What R-value per inch does open-cell spray polyurethane foam (ocSPF) typically provide?

Answer: R-3.5 to R-3.8 per inch

Open-cell SPF provides approximately R-3.5 to R-3.8 per inch due to its lower density and partially open cell structure, compared to about R-6 per inch for closed-cell SPF.

What is a key limitation of using a blower door to identify air leakage locations versus quantifying total air leakage?

Answer: Locating leaks requires additional diagnostic tools like smoke pencils or infrared cameras; the blower door only measures total leakage

The blower door quantifies total envelope leakage (CFM50) but does not identify locations; smoke pencils, theatrical fog, or IR thermography are needed to pinpoint specific leaks.