CLC Lighting System Commissioning & Quality Assurance 2 — Questions and Answers
Question 1: What is the correct method for measuring illuminance during commissioning according to IES standards?
- Take readings only directly beneath each luminaire
- Take measurements on a defined grid pattern at the specified work plane height (Correct answer)
- Measure only at task surfaces and ignore circulation areas
- Take a single measurement at the brightest point in the space
Correct answer: Take measurements on a defined grid pattern at the specified work plane height
IES standards require measurements taken on a grid pattern at the work plane height to accurately calculate average illuminance across the entire space.
Question 2: What does functional testing of a daylight harvesting control system primarily verify?
- The R9 color rendering value of installed luminaires
- That the photosensor correctly adjusts electric light levels as daylight levels change (Correct answer)
- The thermal performance of LED drivers under load
- The emergency battery backup capacity of the system
Correct answer: That the photosensor correctly adjusts electric light levels as daylight levels change
Functional testing confirms the photosensor correctly dims or switches off electric lighting in response to changing daylight, maintaining the target illuminance level.
Question 3: What is the purpose of 'burn-in' testing for new LED luminaire installations?
- To test the fire resistance rating of luminaire housings
- To allow initial operating hours that reveal early component failures before owner acceptance (Correct answer)
- To measure lumen depreciation over the fixture's full rated lifetime
- To verify the IP rating by exposing fixtures to wet conditions
Correct answer: To allow initial operating hours that reveal early component failures before owner acceptance
Burn-in testing operates luminaires for an initial period to identify early-life (infant mortality) failures before the system is accepted by the owner.
Question 4: During LED dimmer commissioning, which performance parameter is most critical to verify?
- The fixture's CRI rating at full light output
- Smooth dimming without flicker, strobing, drop-out, or audible noise across the full range (Correct answer)
- That photometric data matches published catalog specifications
- That mounting height matches the design drawings
Correct answer: Smooth dimming without flicker, strobing, drop-out, or audible noise across the full range
LED dimmers must be verified for smooth operation across the full dimming range, since incompatible dimmer-driver combinations commonly cause flicker, noise, or drop-out.
Question 5: What is the primary purpose of a lighting control narrative document?
- To record brand and model numbers of all installed control devices
- To describe in plain language how the lighting control system should operate in each scenario (Correct answer)
- To list the electrical panel schedules for all lighting circuits
- To specify wiring diagrams for low-voltage control connections
Correct answer: To describe in plain language how the lighting control system should operate in each scenario
A control narrative provides a plain-language description of how the system responds in each mode or scenario, which guides commissioning verification and owner training.
Question 6: Which ASHRAE document is most directly relevant to the commissioning process for building systems including lighting?
- ASHRAE 62.1
- ASHRAE 55
- ASHRAE Guideline 0 (Correct answer)
- ASHRAE 90.1
Correct answer: ASHRAE Guideline 0
ASHRAE Guideline 0 establishes the commissioning process methodology for new and existing buildings, covering all building systems including lighting.
Question 7: What is typically included in a lighting commissioning pre-functional checklist?
- Only the energy cost projections for the completed lighting system
- Verification that equipment is correctly installed, labeled, and accessible before functional testing begins (Correct answer)
- A complete photometric re-analysis of all installed fixtures
- The warranty terms for each installed product
Correct answer: Verification that equipment is correctly installed, labeled, and accessible before functional testing begins
Pre-functional checklists verify installation completeness and correctness before proceeding to functional testing, catching basic installation errors early in the process.
CLC Lighting System Commissioning & Quality Assurance 2
What is the correct method for measuring illuminance during commissioning according to IES standards?