CLD Daylighting Design 5

Question 1

A CLD candidate is asked to evaluate daylighting in an existing building. Which instrument would directly measure interior illuminance at a workplane?

Accepted Answer

Calibrated illuminance meter (lux meter)

Answer

A calibrated illuminance meter (lux meter) with a cosine-corrected photocell measures illuminance (lux or footcandles) at a surface, which is the standard metric for workplane daylighting evaluation.

Question 2

How does increasing the reflectance of interior ceiling and wall surfaces affect daylighting performance?

Accepted Answer

It increases daylight levels in the interior by redirecting inter-reflected light deeper into the space

Answer

High-reflectance interior surfaces bounce daylight from surface to surface, increasing both the depth of daylight penetration and the overall illuminance in the space through inter-reflections.

Question 3

The solar altitude angle at which a horizontal overhang just blocks direct sun from entering a window at a specific time is known as the:

Accepted Answer

Profile angle (or shadow angle)

Answer

The profile angle (shadow angle) is the vertical angle of the sun's rays projected onto a plane perpendicular to the window wall, which determines whether a horizontal overhang will cast a shadow on the glazing.

Question 4

Which daylighting strategy is most effective for a school classroom to provide diffuse illumination without direct solar penetration on the learning surface?

Accepted Answer

Bilateral daylighting with north-facing primary windows and south-facing high windows with overhangs

Answer

Bilateral daylighting using north windows for steady diffuse light and south high windows with overhangs to admit controlled winter sun provides balanced, glare-free illumination appropriate for classrooms.

Question 5

In IES LM-83-12, the spatial Daylight Autonomy target of sDA300/50% means that:

Accepted Answer

At least 50% of the regularly occupied floor area must meet or exceed 300 lux for at least 50% of annual occupied hours

Answer

sDA300/50% requires that at least 50% of the regularly occupied floor area achieves a minimum of 300 lux for at least 50% of annual occupied hours, per IES LM-83.

(CLD) Certified Lighting Designer Practice Test

(CLD) Certified Lighting Designer Practice Test

CLD Daylighting Design 5