CLD Energy Codes 4 — Questions and Answers
Question 1: A designer wants to use luminous ceiling panels in a lobby. Under ASHRAE 90.1, how is the wattage of in-ceiling decorative elements typically counted?
- Excluded entirely as architectural feature
- Included in the LPD calculation for the space (Correct answer)
- Charged only against the decorative allowance
- Counted at 50% of actual wattage due to diffusion
Correct answer: Included in the LPD calculation for the space
All installed wattage, including decorative luminous ceiling panels, is included in the LPD calculation unless a specific exemption applies.
Question 2: Which lighting control technology best meets ASHRAE 90.1's requirement for 'daylight responsive controls' in a primary sidelit daylit zone?
- Manual dimmer accessible to occupants
- Photosensor-based continuous or stepped dimming system (Correct answer)
- Occupancy sensor with vacancy mode
- Time-clock programmed to dim at noon
Correct answer: Photosensor-based continuous or stepped dimming system
A photosensor connected to a dimming or switching system that responds to measured daylight levels satisfies ASHRAE 90.1's daylight responsive control requirement.
Question 3: Under ASHRAE 90.1, which of the following luminaire types is typically EXEMPT from interior LPD calculations?
- Task luminaires on adjustable arms at workstations
- Theatrical stage lighting (Correct answer)
- Display case lighting in a museum
- Pendant luminaires over a reception desk
Correct answer: Theatrical stage lighting
ASHRAE 90.1 exempts theatrical, stage, and studio lighting used for performances and video production from interior LPD calculations.
Question 4: A healthcare facility wants to comply with ASHRAE 90.1 while providing high-quality exam room lighting. Which compliance path gives the designer the most flexibility to exceed base LPD values?
- Space-by-space prescriptive method with no trade-off
- Building area method with whole-building averaging (Correct answer)
- Mandatory controls only with no LPD limit
- LEED equivalent performance path
Correct answer: Building area method with whole-building averaging
The building area method allows a designer to use higher wattage in critical spaces like exam rooms as long as the entire building's total wattage stays within the allowed limit.
Question 5: California Title 24 Part 6 requires multi-level lighting controls in most indoor spaces. What does 'multi-level' mean in this context?
- At least three distinct dim levels including off
- Lighting that can be adjusted from multiple wall stations
- Two or more levels of light output above zero, plus off (Correct answer)
- Separate switching circuits for each row of luminaires
Correct answer: Two or more levels of light output above zero, plus off
Title 24 defines multi-level as providing at least one intermediate level of light output (between full-on and off) in addition to full output and the off state.
Question 6: Under ASHRAE 90.1, what is the maximum allowed wattage per linear foot for general-purpose office open-plan LPD (approximate current value)?
- 0.5 W/sq ft
- 0.82 W/sq ft (Correct answer)
- 1.1 W/sq ft
- 1.5 W/sq ft
Correct answer: 0.82 W/sq ft
ASHRAE 90.1-2019 sets the open plan office LPD at approximately 0.82 W/sq ft under the space-by-space method.
Question 7: A retail store installs track lighting to highlight merchandise. Under ASHRAE 90.1, how is plug-in track lighting typically handled in LPD calculations?
- Excluded because it is plug-in equipment
- Calculated at the track's rated circuit amperage times voltage (Correct answer)
- Counted only if above 150W per head
- Fully exempt as point-of-sale display
Correct answer: Calculated at the track's rated circuit amperage times voltage
ASHRAE 90.1 requires plug-in track lighting to be included in LPD calculations using the rated circuit capacity (amperage × voltage) of the track, not just the currently installed lamp wattage.
CLD Energy Codes 4
A designer wants to use luminous ceiling panels in a lobby.
Under ASHRAE 90.1, how is the wattage of in-ceiling decorative elements typically counted?