CLD Outdoor Lighting 3

Question 1

The Dark Sky Association's five-zone system (E0–E4) is based on which primary environmental characteristic?

Accepted Answer

Ambient nighttime brightness of the surrounding environment

Answer

The IDA/IES Model Lighting Ordinance environmental zones E0–E4 are defined by the existing ambient brightness of the nighttime environment, from pristine dark sky (E0) to urban core (E4).

Question 2

Which performance metric is most relevant when evaluating an outdoor LED fixture's resistance to photometric degradation in a coastal, salt-air environment?

Accepted Answer

IP66 ingress protection rating

Answer

IP66 (dust-tight + high-pressure water jets) indicates a sealed optical chamber that resists salt-air corrosion and condensation, which is critical in coastal environments.

Question 3

When designing parking lot lighting, the IES RP-20 recommends horizontal illuminance calculations at which plane?

Accepted Answer

0.0m — finished grade (ground plane)

Answer

IES RP-20 specifies horizontal illuminance for parking facilities measured at grade (0m), the surface where vehicles and pedestrians interact.

Question 4

A designer wants to minimize the ecological impact of a bridge lighting installation on bat populations. Which practice is most effective?

Accepted Answer

Direct all light strictly downward and reduce intensity along bat flight corridors

Answer

Bats rely on dark corridors for navigation and foraging; directing light strictly downward and keeping bat flight paths unlit preserves these ecological corridors.

Question 5

In roadway lighting design, 'veiling luminance' primarily affects driver vision by:

Accepted Answer

Reducing perceived contrast of objects on the road ahead

Answer

Veiling luminance superimposed on the retina by bright glare sources reduces the perceived contrast between an object and its background, reducing visibility.

(CLD) Certified Lighting Designer Practice Test

(CLD) Certified Lighting Designer Practice Test

CLD Outdoor Lighting 3