CEM Lighting Systems and Controls 3

Question 1

A lighting energy audit should measure which of the following?

Accepted Answer

Lamp wattage, fixture count, operating hours, and ballast losses

Answer

A complete lighting audit quantifies installed wattage including ballast losses, fixture inventory, and annual operating hours to calculate baseline energy use.

Question 2

What is the primary benefit of installing occupancy sensors in private offices?

Accepted Answer

Energy savings of 20-60% by eliminating lighting in unoccupied spaces

Answer

Studies show occupancy sensors in private offices achieve 20-60% lighting energy savings because offices are vacant for significant portions of the workday.

Question 3

Which metric best represents the overall efficiency of a luminaire including lamp and ballast?

Accepted Answer

Luminaire efficacy (system lumens per watt)

Answer

Luminaire efficacy (system lm/W) accounts for lamp output, ballast losses, and fixture optical efficiency, providing a complete measure of system performance.

Question 4

Delamping (removing excess lamps) is a quick energy-saving measure that is most effective when:

Accepted Answer

Illuminance levels significantly exceed IES recommended values

Answer

When measured illuminance greatly exceeds recommended footcandle levels, removing lamps reduces energy without impairing visual comfort or task performance.

Question 5

The Illuminating Engineering Society (IES) publishes recommended illuminance levels primarily to:

Accepted Answer

Define minimum light levels for safe and productive visual tasks

Answer

IES recommended illuminance levels represent minimum light needed for specific visual tasks to ensure safety, comfort, and productivity without over-lighting.

CEM - Certified Energy Manager Practice Test

CEM - Certified Energy Manager Practice Test

CEM Lighting Systems and Controls 3