CLD Interior Lighting 5

Question 1

A specifier notes that a LED driver has a Power Factor (PF) of 0.55. What is the primary concern with this specification?

Accepted Answer

The driver draws more apparent power from the electrical system than real power, increasing utility demand charges

Answer

A low power factor means the driver draws significant reactive power from the grid, increasing apparent power (kVA) demand and potentially raising utility costs and requiring larger electrical infrastructure.

Question 2

In stairwell and egress lighting design per NFPA 101 Life Safety Code, the minimum average illuminance at the tread surface during normal operation is:

Accepted Answer

1 fc (10 lux)

Answer

NFPA 101 requires a minimum of 1 fc (10 lux) at the walking surface along egress paths during normal occupied use.

Question 3

A designer is selecting a luminaire for a space with a very low ceiling (8 ft) and wants to avoid hot spots. Which aperture size is preferable for a recessed downlight?

Accepted Answer

6-inch aperture

Answer

In low-ceiling spaces, a larger aperture (6-inch) distributes light more broadly with lower peak luminance at the aperture, reducing perceptible bright spots and glare at close viewing angles.

Question 4

The term 'efficacy' as applied to a luminaire (system efficacy) is expressed as:

Accepted Answer

Lumens per watt (lm/W) of the complete luminaire system including driver

Answer

System efficacy (lm/W) is the total luminous flux delivered by the luminaire divided by the total input power consumed by the complete system, including the driver.

Question 5

In a high-end residential kitchen, a designer wants to prevent shadows on the countertop work surface from overhead cabinet doors. The best solution is to:

Accepted Answer

Install under-cabinet task lighting beneath the overhead cabinets

Answer

Under-cabinet lighting positioned beneath overhead cabinets illuminates the countertop directly, eliminating shadow cast by cabinets that overhead fixtures would otherwise cause.

(CLD) Certified Lighting Designer Practice Test

(CLD) Certified Lighting Designer Practice Test

CLD Interior Lighting 5