CLD Cheat Sheet 2026

The 30 highest-yield CLD facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which end-of-life concern is unique to fluorescent lamps compared to LED luminaires in sustainability planning? → Mercury content requiring RCRA hazardous waste handling
2. Which professional attribute is most valued in lighting fundamentals within the CLD field? → Accountability and commitment to standards
3. Which LEED v4 credit requires spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE) as the primary simulation metrics? → IEQ Credit: Daylight
4. Which approach best demonstrates mastery of controls and dimming in CLD practice? → Applying principles to novel situations with sound judgment
5. Which IES standard provides guidelines for energy-efficient exterior roadway and area lighting? → IES RP-8
6. When a jurisdiction adopts the 2021 IECC, which lighting control is typically required for all interior spaces greater than 5,000 ft²? → Automatic shutoff controls
7. Maintained illuminance refers to: → The average illuminance level at which maintenance should be performed
8. Luminous intensity is measured in which unit? → Candela
9. What is the spectral power distribution (SPD) of a light source? → A graph showing radiant power emitted at each wavelength across the visible spectrum
10. Which type of occupancy sensor technology is best suited for detecting minor motion in large open-plan offices? → Dual-technology (PIR + ultrasonic)
11. What is the best practice for maintaining daylighting design performance over time? → Implement scheduled preventive maintenance
12. 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
13. Which NFPA standard governs the installation and performance of emergency and standby power systems that supply egress lighting? → NFPA 110
14. Which dimming protocol uses a two-wire digital bus to individually address up to 64 devices per segment? → DALI
15. IES TM-21 is used in conjunction with LM-80 test data to accomplish what? → Project long-term LED lumen maintenance beyond the tested period
16. A south-facing clerestory window primarily delivers daylight to which area of a room? → The deeper interior zones away from the primary façade
17. ASHRAE 90.1 requires automatic shutoff controls for interior lighting in spaces larger than what square footage threshold? → 2,500 sq ft
18. What is the primary function of a 0–10 V dimming signal? → Low‑voltage DC dimming control
19. Under NFPA 70 (National Electrical Code), outdoor luminaires installed in wet locations must be listed and labeled for: → 'Wet location' use
20. What does the term 'efficacy' mean when applied to a light source? → The ratio of luminous flux output to electrical power input, expressed in lumens per watt
21. Which section of the International Building Code (IBC) primarily governs means-of-egress lighting levels? → Section 1008
22. When planning a project in Certified Lighting Designer, which element should be established FIRST? → Clear objectives, scope, and success criteria
23. Which US federal regulation sets minimum efficacy standards for general service lamps sold in the country, complementing building energy codes? → DOE Lamp Rule under EPCA
24. Which approach best demonstrates mastery of energy codes in CLD practice? → Applying principles to novel situations with sound judgment
25. Which protocol allows lighting systems to communicate energy data to building management systems for sustainability monitoring? → BACnet
26. A restaurant designer wants to create a candlelight effect using electric lighting. Which combination of luminaire characteristics best achieves this? → Low-lumen 1800K–2200K sources with warm-dim capability
27. In ASHRAE 90.1, what is the primary compliance pathway for interior lighting energy in a commercial building? → Lighting Power Density (LPD) limits
28. A designer calculates Annual Energy Use Intensity (EUI) for lighting. Which unit is correct? → kBtu/ft²/year
29. A lighting designer specifies luminaires with a Unified Glare Rating (UGR) below 19. What sustainability co-benefit does this primarily provide? → Improved occupant visual comfort and productivity
30. 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: → Bi-level switching