CLD Energy Codes 5 — Questions and Answers
Question 1: Under ASHRAE 90.1, a 'vacancy sensor' differs from an 'occupancy sensor' primarily in that it:
- Turns lights on automatically but requires manual turn-off
- Requires manual turn-on but turns lights off automatically when space is vacant (Correct answer)
- Works only in outdoor applications
- Requires a separate photosensor to function
Correct answer: Requires manual turn-on but turns lights off automatically when space is vacant
A vacancy sensor (manual-on/auto-off) requires an occupant to manually turn on the lights but switches them off automatically after the space is vacated.
Question 2: Which US federal regulation sets minimum efficacy standards for general service lamps sold in the country, complementing building energy codes?
- EPACT 1992
- DOE Lamp Rule under EPCA (Correct answer)
- ASHRAE Standard 189.1
- EPA ENERGY STAR for luminaires
Correct answer: DOE Lamp Rule under EPCA
The Department of Energy's lamp efficacy rules under the Energy Policy and Conservation Act (EPCA) set minimum lumens-per-watt requirements for general service lamps sold in the US.
Question 3: A designer is evaluating two control systems for a large office: System A uses scheduled time-clock shutoff only; System B adds occupancy sensing. Under ASHRAE 90.1, which is compliant for interior spaces over 2,500 sq ft?
- System A only
- System B only (Correct answer)
- Both systems are compliant
- Neither; only daylight sensors satisfy the requirement
Correct answer: System B only
ASHRAE 90.1 requires automatic shutoff for spaces over 2,500 sq ft; occupancy sensing satisfies this, and when combined with time-clock control it exceeds the minimum requirement.
Question 4: In ASHRAE 90.1's exterior lighting requirements, which application is classified as 'tradable' (subject to LPD limits) versus 'non-tradable' (separately regulated)?
- Parking lot lighting is non-tradable; facade lighting is tradable
- Parking lot lighting is tradable; emergency egress lighting is non-tradable (Correct answer)
- Landscape lighting is non-tradable; signage lighting is tradable
- All exterior lighting is tradable under a single allowance
Correct answer: Parking lot lighting is tradable; emergency egress lighting is non-tradable
ASHRAE 90.1 categorizes exterior lighting as tradable (can be redistributed among applications like parking and facades) and non-tradable (fixed applications like emergency egress that cannot offset other categories).
Question 5: A designer is specifying luminaires for a LEED v4 project that also must comply with ASHRAE 90.1-2016. LEED EAp2 (Minimum Energy Performance) requires compliance with which standard?
- IECC 2012 or local code, whichever is more stringent
- ASHRAE 90.1-2010 or local code, whichever is more stringent
- ASHRAE 90.1-2016 or local code, whichever is more stringent (Correct answer)
- ASHRAE 189.1 for all LEED projects
Correct answer: ASHRAE 90.1-2016 or local code, whichever is more stringent
LEED v4 EAp2 references ASHRAE 90.1-2010 as the baseline; however, many jurisdictions reference newer editions, and LEED requires compliance with the more stringent of the referenced standard or local code.
Question 6: What does the acronym 'LPD' stand for in the context of energy codes for lighting?
- Lumen Power Density
- Lighting Power Density (Correct answer)
- Lamp Performance Distribution
- Load Power Demand
Correct answer: Lighting Power Density
LPD stands for Lighting Power Density, expressed in watts per square foot (W/sq ft), representing the maximum allowed installed lighting power per unit area.
Question 7: Under ASHRAE 90.1, which of the following is a valid strategy for a designer to reduce a space's effective LPD contribution when task lighting is used at individual workstations?
- Subtract all task light wattage from the space's LPD calculation automatically
- Use the 'furniture-mounted task lighting' exemption to exclude qualifying fixtures from the calculation (Correct answer)
- Apply for a code variance through the Authority Having Jurisdiction
- Reclassify the space as residential to use a different LPD table
Correct answer: Use the 'furniture-mounted task lighting' exemption to exclude qualifying fixtures from the calculation
ASHRAE 90.1 allows qualifying furniture-mounted (plug-in) task luminaires to be excluded from the space's LPD calculation when they meet specific criteria, enabling lower ambient lighting levels.
CLD Energy Codes 5
Under ASHRAE 90.1, a 'vacancy sensor' differs from an 'occupancy sensor' primarily in that it: