Sustainable & Energy-Efficient Lighting Solutions Flashcards

Under LEED v4.1, which credit category directly rewards reductions in exterior lighting power and control of uplight?

Answer: Sustainable Sites: Light Pollution Reduction

LEED v4.1 Sustainable Sites credit 'Light Pollution Reduction' awards points for meeting uplight, backlight, and glare limits using the BUG rating method.

What is the key difference between 'connected load' and 'demand load' when calculating lighting energy use?

Answer: Connected load is the sum of all installed fixture wattages; demand load accounts for controls reducing average power draw

Connected load is the total installed wattage, while demand load reflects actual average consumption after controls (dimming, occupancy) reduce operating levels.

A hospital corridor is lit to 30 fc for normal operation and automatically steps down to 5 fc when unoccupied at night. This strategy is best described as:

Answer: Bi-level switching

Bi-level switching (or stepped dimming) uses occupancy sensors to reduce light levels to a standby level rather than switching fully off, balancing safety with energy savings.

Which lamp type is prohibited by US DOE regulations phased in from August 2023 due to its inefficiency?

Answer: General service incandescent and halogen lamps below 45 lm/W

The DOE's 2023 ruling effectively banned general service lamps that do not meet a 45 lm/W minimum efficacy, eliminating most incandescent and halogen A-lamps.

In a daylight harvesting system, 'closed-loop' control differs from 'open-loop' control because it:

Answer: Measures actual workplane illuminance and adjusts electric light to maintain a setpoint

Closed-loop systems use a photosensor aimed at the task plane to measure combined daylight and electric light, continuously adjusting output to hit a target illuminance level.

What is the primary sustainability advantage of using solid-state lighting (SSL) over high-intensity discharge (HID) sources in exterior applications?

Answer: SSL eliminates the restrike delay and contains no mercury, while typically achieving higher efficacy

LED-based SSL has no restrike delay (important for safety), contains no mercury (reducing hazardous waste), and modern products exceed HID efficacy in most applications.

A Life Cycle Cost (LCC) analysis for a lighting project should include all of the following EXCEPT:

Answer: The aesthetic design fee paid to the architect

LCC captures hardware, installation, energy, and maintenance costs over a system's life; design fees are a project cost but are not part of the lighting system's operational life cycle.