Outdoor Lighting Flashcards

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

Answer: Ambient nighttime brightness of the surrounding environment

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).

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

Answer: IP66 ingress protection rating

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.

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

Answer: 0.0m — finished grade (ground plane)

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

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

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

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

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

Answer: Reducing perceived contrast of objects on the road ahead

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

Which mounting configuration is typically used for sports field floodlights to achieve the highest uniformity across a rectangular playing field?

Answer: Four corner poles with symmetrical aiming

Four-corner pole configurations with symmetrically aimed floodlights provide the most uniform overlapping coverage across a rectangular field, as recommended by IES RP-6.

What is the key advantage of using a modular LED engine design in outdoor area luminaires for a large municipal project?

Answer: Ability to replace only the LED module at end-of-life without replacing the full fixture housing

Modular LED engines allow the city to replace only the light source component when it reaches L70, avoiding costly full-fixture replacement and reducing long-term maintenance costs.