CLD Outdoor Lighting 4

Question 1

A roadway lighting project requires maintained average luminance of 1.0 cd/m² at end of design life. If the initial design delivers 1.4 cd/m², what Light Loss Factor (LLF) was assumed?

Accepted Answer

0.71

Answer

LLF = maintained value ÷ initial value = 1.0 ÷ 1.4 ≈ 0.71, meaning the designer accounted for ~29% depreciation over the design life.

Question 2

Which ANSI/IES standard specifically addresses outdoor sports and recreational area lighting?

Accepted Answer

IES RP-6

Answer

IES RP-6 'Sports and Recreational Area Lighting' provides illuminance recommendations, uniformity criteria, and glare ratings for various sports and competition levels.

Question 3

An outdoor museum facade luminaire uses a narrow-beam (10°) LED projector. Technicians report color shift across the beam at the edges. What is the most likely cause?

Accepted Answer

Chromatic aberration from the lens design separating phosphor emission wavelengths at oblique angles

Answer

Narrow-beam lenses can exhibit chromatic aberration at the beam edge where light passes through at oblique angles, causing blue or yellow fringing from the phosphor-converted LED source.

Question 4

For a high-mast lighting installation (pole height ≥20m), which factor most significantly increases maintenance costs compared to standard-height pole lighting?

Accepted Answer

Requirement for bucket-truck or climbing access to service the luminaire head

Answer

High-mast poles require specialized access equipment (bucket trucks or lowering rings) for maintenance, making each service visit substantially more expensive than for standard pole heights.

Question 5

A landscape architect requests 'moonlighting' for a garden. Which technique best achieves this effect?

Accepted Answer

Mounting warm-white fixtures high in tree canopy aimed downward to cast dappled shadows

Answer

Moonlighting places warm-white luminaires high in tree branches angled downward, mimicking the natural appearance of moonlight filtering through a canopy and creating natural shadow patterns below.

(CLD) Certified Lighting Designer Practice Test

(CLD) Certified Lighting Designer Practice Test

CLD Outdoor Lighting 4