CLC Lighting Controls & Technologies 3 — Questions and Answers
Question 1: Which ASHRAE/IES Standard 90.1 requirement mandates automatic shutoff controls for lighting in most commercial buildings?
- Section 9 (Lighting) (Correct answer)
- Section 6 (HVAC)
- Section 7 (Service Water Heating)
- Section 5 (Building Envelope)
Correct answer: Section 9 (Lighting)
ASHRAE 90.1 Section 9 covers lighting energy efficiency requirements, including mandatory automatic shutoff controls in commercial spaces.
Question 2: What does the term 'lumen maintenance' refer to in the context of LED driver dimming?
- The ability of a driver to sustain consistent light output as the LED ages (Correct answer)
- The process of cleaning luminaire lenses to restore output
- Increasing wattage over time to compensate for lumen depreciation
- The driver's protection against voltage spikes
Correct answer: The ability of a driver to sustain consistent light output as the LED ages
Lumen maintenance describes how well a driver or system preserves rated light output over the operational life of the LED source.
Question 3: In a BACnet/IP integration with a lighting control system, what role does the BACnet object type 'Analog Output' typically serve?
- Sending a variable setpoint such as a dimming level to a field device (Correct answer)
- Reading a binary on/off status from a relay
- Storing historical energy data logs
- Defining a scheduled event in the BACnet calendar
Correct answer: Sending a variable setpoint such as a dimming level to a field device
BACnet Analog Output objects write continuous variable values—like a 0–100% dim command—to controlled devices in the field.
Question 4: Which color rendering metric better captures the ability of a light source to render saturated colors compared to CRI Ra?
- IES TM-30 Rf and Rg (Correct answer)
- CCT (Correlated Color Temperature)
- CIE Ra extended to R15
- Luminous efficacy (lm/W)
Correct answer: IES TM-30 Rf and Rg
IES TM-30 uses 99 reference samples and reports both fidelity (Rf) and gamut (Rg), providing a more complete color rendering picture than the 8-sample CRI Ra.
Question 5: A retail store uses tunable white LED fixtures to shift CCT throughout the day. Which human-centric lighting benefit does this PRIMARILY target?
- Circadian rhythm alignment and alertness regulation (Correct answer)
- Emergency egress compliance
- Reducing glare on merchandise
- Improving color accuracy for inventory
Correct answer: Circadian rhythm alignment and alertness regulation
Tunable white systems shift between warm and cool CCT to mirror the natural daylight cycle, supporting circadian health and alertness in occupants.
Question 6: What is the purpose of a 'hold-on' time setting in an occupancy sensor controller?
- It keeps lights on for a set period after the last detected motion before turning them off (Correct answer)
- It delays light turn-on after motion is first detected
- It prevents re-triggering within a defined window after lights turn off
- It sets the maximum time lights can remain at full brightness
Correct answer: It keeps lights on for a set period after the last detected motion before turning them off
The hold-on (or time delay) setting prevents premature shutoff by maintaining illumination for a specified duration after the sensor last detects movement.
Question 7: In a Power over Ethernet (PoE) lighting system, what standard governs the maximum power delivery per port for high-power luminaires?
- IEEE 802.3bt (Type 4, up to 90W) (Correct answer)
- IEEE 802.3af (up to 15.4W)
- IEEE 802.3at (up to 30W)
- IEEE 802.3az (Energy Efficient Ethernet)
Correct answer: IEEE 802.3bt (Type 4, up to 90W)
IEEE 802.3bt (PoE++) Type 4 delivers up to 90W per port, enabling high-wattage luminaires and additional sensors on a single Ethernet cable.
CLC Lighting Controls & Technologies 3
Which ASHRAE/IES Standard 90.1 requirement mandates automatic shutoff controls for lighting in most commercial buildings?