CLD Sustainability 4 — Questions and Answers
Question 1: A museum replaces fiber optic display lighting with LED. What is the primary sustainability advantage beyond energy savings?
- LEDs emit no UV or IR radiation, eliminating the need for UV filters that become waste (Correct answer)
- LEDs have a wider color gamut for better artifact rendering
- LED systems require no control systems
- LEDs are always dimmable without additional hardware
Correct answer: LEDs emit no UV or IR radiation, eliminating the need for UV filters that become waste
LEDs produce negligible UV and IR radiation, eliminating the need for UV filter accessories on fixtures and reducing material waste and artifact degradation risk.
Question 2: Which WELL Building Standard feature is most directly related to sustainable lighting for occupant health?
- Feature L01 – Light Exposure and Education (Correct answer)
- Feature L04 – Glare Control
- Feature L07 – Electric Light Quality
- Feature L06 – Color Quality
Correct answer: Feature L01 – Light Exposure and Education
WELL Feature L01 addresses circadian light exposure levels and educates occupants on optimizing personal light exposure to support biological rhythms and overall health.
Question 3: A designer calculates Annual Energy Use Intensity (EUI) for lighting. Which unit is correct?
- kWh/year
- kBtu/ft²/year (Correct answer)
- lm/W
- W/ft²
Correct answer: kBtu/ft²/year
EUI is expressed in kBtu per square foot per year (or kWh/m²/year in metric), normalizing annual energy consumption by building area for comparison.
Question 4: In a warehouse with high bays, which lighting strategy most effectively combines energy savings with good vertical illumination?
- High-bay LED with occupancy sensors and high-reflectance ceiling finishes (Correct answer)
- Low-bay fluorescent on a time clock
- High-intensity discharge (HID) with manual switching
- Indirect LED cove lighting at roof level
Correct answer: High-bay LED with occupancy sensors and high-reflectance ceiling finishes
High-bay LED luminaires combined with occupancy sensors and high-reflectance surfaces maximize delivered light, reduce watts-on time, and improve energy performance in warehouse environments.
Question 5: Which end-of-life concern is unique to fluorescent lamps compared to LED luminaires in sustainability planning?
- High operating temperature disposal hazard
- Mercury content requiring RCRA hazardous waste handling (Correct answer)
- Radioactive phosphor coating
- Explosive pressurized gas cylinder risk
Correct answer: Mercury content requiring RCRA hazardous waste handling
Fluorescent lamps contain mercury and are classified as hazardous waste under RCRA in the US, requiring special recycling programs rather than standard landfill disposal.
Question 6: A project uses a Lighting Power Allowance (LPA) calculation method instead of LPD. What is the key difference?
- LPA allows additional wattage credits for specific features like decorative lighting or task lighting (Correct answer)
- LPA uses luminous efficacy instead of wattage
- LPA is based on occupant count rather than floor area
- LPA only applies to exterior lighting
Correct answer: LPA allows additional wattage credits for specific features like decorative lighting or task lighting
The Lighting Power Allowance method in ASHRAE 90.1 adds a base allowance per area plus extra credits for specific applications (display, decorative, task), potentially allowing more total wattage than the LPD method.
Question 7: What is the primary reason a high Color Rendering Index (CRI) alone does not guarantee sustainable quality lighting?
- High CRI sources always have lower efficacy
- CRI measures average rendering across 8 test samples and can miss specific wavelength accuracy, including red saturation (R9) (Correct answer)
- High CRI luminaires cannot be dimmed
- CRI only applies to interior spaces
Correct answer: CRI measures average rendering across 8 test samples and can miss specific wavelength accuracy, including red saturation (R9)
CRI uses only 8 pastel-colored test samples and can miss critical rendering performance, particularly for saturated reds (R9), so high CRI alone does not ensure complete color quality.
CLD Sustainability 4
A museum replaces fiber optic display lighting with LED.
What is the primary sustainability advantage beyond energy savings?