NABCEP Building and Fire Codes 3 — Questions and Answers
Question 1: Under the 2021 IFC, what is the required minimum width of an access pathway across a flat roof (slope < 2:12) for a PV-covered Group R-3 building?
- 18 inches
- 6 feet
- 4 feet
- 36 inches (Correct answer)
Correct answer: 36 inches
The 2021 IFC requires 36-inch-wide access pathways across the center of flat roofs on Group R-3 buildings to allow firefighter traverse.
Question 2: When a PV system is installed on a building requiring a Type I or II construction, what limitation applies to PV module materials per the IBC?
- Modules must be non-combustible or have a Class A fire rating (Correct answer)
- Modules must be UL 1703 listed only
- Modules must be tempered glass exclusively
- No combustible materials are allowed within 10 feet of the modules
Correct answer: Modules must be non-combustible or have a Class A fire rating
IBC Type I and II construction requires materials to be non-combustible; PV modules used on these buildings must be non-combustible or carry a Class A fire classification.
Question 3: What is the primary purpose of the 'rapid shutdown' requirement in NEC Article 690.12 from a fire code perspective?
- Reduce arc flash hazard during normal maintenance
- Limit PV system voltage to safe levels in the array boundary within 30 seconds of shutdown initiation (Correct answer)
- Disconnect AC power to inverters automatically during a grid outage
- Prevent reverse current from the battery into the array
Correct answer: Limit PV system voltage to safe levels in the array boundary within 30 seconds of shutdown initiation
NEC 690.12 rapid shutdown limits conductors inside the array boundary to 30V within 30 seconds, protecting firefighters from electrocution while working on or near the roof.
Question 4: Under California's Title 24 fire-code amendments, which roof zone classification prohibits PV array installation on steep-slope roofs for new Group R-3 construction?
- Zone 1 (within 18 inches of valleys) (Correct answer)
- Zone 3 (within 36 inches of hips)
- Zone 2 (within 18 inches of ridges and hips)
- No zone prohibition; setbacks only
Correct answer: Zone 1 (within 18 inches of valleys)
California Title 24 prohibits PV modules in Zone 1, the area within 18 inches of roof valleys, because valleys are primary fire travel corridors.
Question 5: According to NFPA 855, lithium-ion ESS installations exceeding 20 kWh in a Group B occupancy must be protected by which system?
- Smoke detection only
- Automatic sprinkler system complying with NFPA 13 (Correct answer)
- Portable fire extinguishers rated 10-BC minimum
- Carbon monoxide detectors with alarm relay
Correct answer: Automatic sprinkler system complying with NFPA 13
NFPA 855 requires automatic sprinkler protection per NFPA 13 for ESS installations exceeding 20 kWh in commercial (Group B) occupancies.
Question 6: What does the IFC require for PV system DC disconnect labeling when the disconnecting means is not within sight of the PV array?
- A permanent plaque indicating the remote location of the disconnect (Correct answer)
- An audible alarm when the disconnect is opened
- A tamper-resistant lock on the remote disconnect
- A second disconnect installed within sight of the array
Correct answer: A permanent plaque indicating the remote location of the disconnect
When the DC disconnect is out of sight of the array, IFC and NEC require a permanent plaque or directory on the remote disconnect indicating the array location.
Question 7: Which IBC section governs the structural design loads for rooftop-mounted PV arrays, requiring they be treated as rooftop structures rather than equipment?
- IBC Section 1607 (Live Loads) (Correct answer)
- IBC Section 1613 (Earthquake Loads)
- IBC Section 1504 (Roof Coverings)
- IBC Section 1603 (Construction Documents)
Correct answer: IBC Section 1607 (Live Loads)
IBC Section 1607 addresses live loads including those imposed by rooftop-mounted PV systems, which must be calculated as rooftop structures with appropriate load combinations.
NABCEP Building and Fire Codes 3
Under the 2021 IFC, what is the required minimum width of an access pathway across a flat roof (slope < 2:12) for a PV-covered Group R-3 building?