BPI Multifamily flashcards
BPI Multifamily · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Stack effect
- The upward movement of air through a building caused by temperature differences; warm air rises and creates positive pressure high and negative pressure low, driving infiltration.
- Pressure boundary
- The continuous plane separating conditioned from unconditioned space; it resists air flow and is the primary target for air sealing in multifamily units.
- Compartmentalization
- The isolation of each dwelling unit's air boundary from adjacent units and common areas to reduce odor, moisture, and pollutant transfer; verified by guarded blower door testing.
- U-value
- The overall heat transfer coefficient of an assembly in Btu/h·ft²·°F; lower U-values indicate better insulation. U = 1/R.
- ASHRAE 62.2 ventilation rate
- Whole-dwelling ventilation formula: Q = 0.03A + 7.5(N+1) CFM, where A is conditioned floor area and N is number of bedrooms.
- Infiltration sensible load
- Sensible heat gain or loss from air leakage, calculated as 1.08 × CFM × ΔT; used to size HVAC and estimate savings from air sealing.
- Thermal bridge
- A path of high heat conductance through an assembly, such as a slab edge or steel stud, that bypasses insulation and increases whole-building heat loss.
- Blower door test
- A diagnostic test that pressurizes or depressurizes a building to 50 Pa and measures airflow (CFM50) to quantify envelope airtightness.
- ACH50 to ACHnat conversion
- Natural infiltration is estimated as ACH50 divided by N, where N typically ranges from 15 to 20 for multifamily buildings, depending on height and exposure.
- Zone pressure diagnostic
- A test using a second manometer to measure pressure differences between zones; changes in pressure when a known opening is created reveal dominant leakage paths.
- Infrared thermography
- An imaging method that detects surface temperature differences to locate insulation gaps, air leakage, and moisture; requires a steady ΔT of at least 10°F.
- Duct leakage test
- Pressurizing the duct system to 25 Pa and measuring airflow (CFM25) to quantify leakage; results are compared with design airflow to determine pass/fail.
- Worst-case depressurization
- A combustion safety test that runs all exhaust fans and closes interior doors to create maximum negative pressure, then checks for flue gas spillage.
- Ambient CO threshold
- The carbon monoxide concentration in conditioned space that triggers action; typically 35 ppm in ambient air during combustion safety testing.
- Moisture meter
- A pin or pinless instrument that measures wood or building material moisture content; readings above 20% indicate active or recent wetting.
- Baseline utility data
- Twelve months of gas and electric bills used to establish pre-retrofit energy consumption and EUI, and to calibrate energy models.
- Energy use intensity (EUI)
- Annual site energy consumption divided by conditioned floor area, expressed in kBtu/ft²·yr; used to compare buildings and track savings.
- Degree-day method
- An estimation technique using heating or cooling degree days and building UA to predict annual energy use: E = UA × HDD × 24 / η.
- Interactive effects
- The phenomenon where savings from one measure change the savings from another, such as air sealing reducing the benefit of added insulation.
- Calibrated energy model
- A simulation adjusted so its annual and monthly energy use matches utility bills within about ±10%, improving savings projections.
- Simple payback
- Installed measure cost divided by annual energy cost savings; a quick screening metric that ignores measure life and discount rates.
- Demand charge
- A utility fee based on the peak power (kW) drawn during a billing period; measures that reduce peak load can yield savings beyond energy charges.
- TMY3 weather file
- A typical meteorological year dataset used in energy modeling to represent long-term average weather conditions for a specific location.
- Source vs site energy
- Site energy is consumed at the building; source energy includes generation and delivery losses, and is used for comparing fuels on a consistent basis.
- Scope of work (SOW)
- A written document specifying location, quantity, material, installation method, and acceptance criteria for each retrofit measure.
- Change order
- A written authorization for work that deviates from the original scope, approved by the program or owner before the work proceeds.
- Air sealing specification
- A scope item listing specific leakage sites, sealant type, and thickness to be applied, with defined acceptance criteria.
- Insulation clearance requirements
- Minimum distances between insulation and heat sources, such as 3 inches around recessed lights and 1 inch from chimneys, to prevent fire hazards.
- Quality control inspection
- A defined verification step at pre-work, rough-in, or final stage, often sampling a percentage of units to confirm SOW compliance.
- ASHRAE 62.2
- The residential ventilation standard that specifies whole-dwelling and local exhaust airflow rates and acceptable indoor air quality requirements.
- ASTM E779
- A standard test method for determining air leakage rate by fan pressurization, commonly used for blower door testing.
- BPI technical standards
- Building Performance Institute documents defining minimum competencies and test procedures for envelope, heating, cooling, and air conditioning work.