CEM Floor Plan Development 3 — Questions and Answers
Question 1: When performing a lighting energy analysis from floor plans, what is the standard unit used to express lighting power density (LPD)?
- Lumens per square foot (lm/ft²)
- Watts per square foot (W/ft²) (Correct answer)
- Foot-candles per watt (fc/W)
- BTUs per hour per square foot (BTU/hr·ft²)
Correct answer: Watts per square foot (W/ft²)
Lighting Power Density (LPD) is expressed in watts per square foot (W/ft²) and is used to compare installed lighting against code maximums.
Question 2: A floor plan indicates open-plan office spaces adjacent to private perimeter offices. What daylighting strategy best leverages both space types?
- Installing skylights only in private offices to maximize daylight access
- Using high partitions to block glare from perimeter windows in open areas
- Lowering partition heights to allow daylight to penetrate from perimeter into the open-plan interior (Correct answer)
- Placing all artificial lighting on the perimeter to supplement natural light
Correct answer: Lowering partition heights to allow daylight to penetrate from perimeter into the open-plan interior
Lower partitions allow daylight from perimeter windows to reach deeper into open-plan areas, reducing artificial lighting energy use.
Question 3: What floor plan characteristic most directly determines the 'window-to-wall ratio' (WWR) used in energy calculations?
- Total glazed area divided by total gross wall area on each facade (Correct answer)
- Number of windows divided by number of exterior walls
- Glazed area divided by conditioned floor area
- Window height divided by floor-to-ceiling height
Correct answer: Total glazed area divided by total gross wall area on each facade
WWR is the ratio of total glazed area to total gross wall area on a given facade, directly affecting solar heat gain and infiltration calculations.
Question 4: On a floor plan, a building has 'internal load-dominated' spaces like data centers adjacent to 'skin load-dominated' perimeter offices. What is the key HVAC zoning implication?
- Both space types should share a single air handling unit for efficiency
- They must be on separate HVAC zones because their conditioning needs conflict throughout the year (Correct answer)
- The data center can use waste heat to condition the perimeter offices year-round
- Internal spaces require more outdoor air ventilation than perimeter spaces
Correct answer: They must be on separate HVAC zones because their conditioning needs conflict throughout the year
Internal load-dominated spaces need year-round cooling while skin-dominated spaces need heating in winter, requiring separate zone control to avoid energy waste.
Question 5: An energy audit floor plan shows that a manufacturing facility has no vestibules at its main entry doors. What energy problem does this indicate?
- Insufficient natural lighting at entry points
- Excessive air infiltration and pressurization losses every time doors open (Correct answer)
- Inadequate structural support for heavy door hardware
- Non-compliant egress path width per life safety codes
Correct answer: Excessive air infiltration and pressurization losses every time doors open
Without vestibules, each door opening creates a direct air exchange between conditioned interior and outdoor conditions, increasing infiltration losses.
Question 6: When scaling a floor plan for energy analysis, an energy manager finds that 1 inch on the drawing equals 8 feet in reality. A room measures 3.5 inches × 2.25 inches on paper. What is its actual area?
- 504 square feet (Correct answer)
- 2,016 square feet
- 63 square feet
- 1,764 square feet
Correct answer: 504 square feet
Actual dimensions are 28 ft × 18 ft = 504 sq ft (3.5 × 8 = 28; 2.25 × 8 = 18; 28 × 18 = 504).
Question 7: A floor plan audit reveals that a hospital has many small, isolated single-occupancy rooms versus open bays. What is the primary HVAC energy implication of this layout?
- Fewer outdoor air changes are required for isolated rooms
- More individual zone controls and reheat are needed, increasing system complexity and energy use (Correct answer)
- Cooling loads are lower in isolated rooms due to reduced occupant density
- Lighting energy is lower because smaller rooms need less illumination
Correct answer: More individual zone controls and reheat are needed, increasing system complexity and energy use
Many individual rooms each require separate pressure and temperature control, leading to more reheat, more controls, and higher overall HVAC energy consumption.
CEM Floor Plan Development 3
When performing a lighting energy analysis from floor plans, what is the standard unit used to express lighting power density (LPD)?