FDNY W27 CERTIFICATE OF FITNESS
SUPERVISION OF STATIONARY ENERGY
STORAGE SYSTEMS (ESS) PRACTICE
EXAM QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2026 Q&A | INSTANT
DOWNLOAD P
1. What is the primary purpose of a stationary energy storage system
(ESS) in a Group R-3 occupancy?
A. To serve as a backup water supply
B. To provide temporary lighting only
C. To store electrical energy for backup power or load management
D. To reduce the need for fire alarms
Rationale: ESS units store energy to provide backup power or manage
electrical loads during peak demand or outages.
2. Which of the following is considered a hazardous condition for a
lithium-ion ESS?
A. Proper ventilation
B. Physical damage or swelling of the battery
C. Temperature within the manufacturer’s limits
D. Correct electrical connections
,Rationale: Physical damage or swelling can indicate thermal runaway, a
key hazard in lithium-ion batteries.
3. How often should the W27 Certificate of Fitness holder inspect the
ESS in Group R-3 occupancies?
A. Once a year
B. At least monthly
C. Only after a fire alarm
D. Only when maintenance is required
Rationale: Monthly inspections ensure that hazards are identified early
and systems remain compliant.
4. What is the maximum allowed indoor ambient temperature for
most lithium-ion ESS installations?
A. 50°C (122°F)
B. 30°C (86°F)
C. 15°C (59°F)
D. 40°C (104°F)
Rationale: High temperatures accelerate battery degradation and
increase the risk of thermal events.
5. Which of the following personal protective equipment (PPE) is
required when inspecting an ESS?
A. Gloves and safety glasses only
B. Insulated gloves, safety glasses, and flame-resistant clothing
C. Earplugs only
D. Hard hat only
Rationale: Proper PPE protects against electrical shock, arc flash, and
chemical hazards from batteries.
6. What should you do if the ESS shows signs of smoke or unusual
odor?
A. Ignore and continue inspection
, B. Evacuate the area and notify the fire department
C. Open the system to check the source
D. Spray water on the unit immediately
Rationale: Smoke or odors indicate a potential thermal runaway;
immediate evacuation and professional intervention are required.
7. How should the area around an ESS be maintained?
A. Cluttered with maintenance tools
B. Accessible only to tenants
C. Clear of combustible materials and easily accessible
D. Sealed with plastic sheets
Rationale: Maintaining a clear area reduces fire risk and ensures
emergency access.
8. What is the recommended method for extinguishing a lithium-ion
ESS fire?
A. Water only
B. Foam only
C. Class D or specialized extinguishing agents
D. Dry towels
Rationale: Lithium-ion fires require agents that do not react violently
with the battery materials.
9. Which code governs stationary ESS installations in Group R-3
occupancies in NYC?
A. NYC Plumbing Code
B. NYC Energy Code
C. NYC Fire Code and NFPA 855
D. NYC Zoning Code
Rationale: NFPA 855 and NYC Fire Code provide standards for fire safety
and installation of ESS systems.
SUPERVISION OF STATIONARY ENERGY
STORAGE SYSTEMS (ESS) PRACTICE
EXAM QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2026 Q&A | INSTANT
DOWNLOAD P
1. What is the primary purpose of a stationary energy storage system
(ESS) in a Group R-3 occupancy?
A. To serve as a backup water supply
B. To provide temporary lighting only
C. To store electrical energy for backup power or load management
D. To reduce the need for fire alarms
Rationale: ESS units store energy to provide backup power or manage
electrical loads during peak demand or outages.
2. Which of the following is considered a hazardous condition for a
lithium-ion ESS?
A. Proper ventilation
B. Physical damage or swelling of the battery
C. Temperature within the manufacturer’s limits
D. Correct electrical connections
,Rationale: Physical damage or swelling can indicate thermal runaway, a
key hazard in lithium-ion batteries.
3. How often should the W27 Certificate of Fitness holder inspect the
ESS in Group R-3 occupancies?
A. Once a year
B. At least monthly
C. Only after a fire alarm
D. Only when maintenance is required
Rationale: Monthly inspections ensure that hazards are identified early
and systems remain compliant.
4. What is the maximum allowed indoor ambient temperature for
most lithium-ion ESS installations?
A. 50°C (122°F)
B. 30°C (86°F)
C. 15°C (59°F)
D. 40°C (104°F)
Rationale: High temperatures accelerate battery degradation and
increase the risk of thermal events.
5. Which of the following personal protective equipment (PPE) is
required when inspecting an ESS?
A. Gloves and safety glasses only
B. Insulated gloves, safety glasses, and flame-resistant clothing
C. Earplugs only
D. Hard hat only
Rationale: Proper PPE protects against electrical shock, arc flash, and
chemical hazards from batteries.
6. What should you do if the ESS shows signs of smoke or unusual
odor?
A. Ignore and continue inspection
, B. Evacuate the area and notify the fire department
C. Open the system to check the source
D. Spray water on the unit immediately
Rationale: Smoke or odors indicate a potential thermal runaway;
immediate evacuation and professional intervention are required.
7. How should the area around an ESS be maintained?
A. Cluttered with maintenance tools
B. Accessible only to tenants
C. Clear of combustible materials and easily accessible
D. Sealed with plastic sheets
Rationale: Maintaining a clear area reduces fire risk and ensures
emergency access.
8. What is the recommended method for extinguishing a lithium-ion
ESS fire?
A. Water only
B. Foam only
C. Class D or specialized extinguishing agents
D. Dry towels
Rationale: Lithium-ion fires require agents that do not react violently
with the battery materials.
9. Which code governs stationary ESS installations in Group R-3
occupancies in NYC?
A. NYC Plumbing Code
B. NYC Energy Code
C. NYC Fire Code and NFPA 855
D. NYC Zoning Code
Rationale: NFPA 855 and NYC Fire Code provide standards for fire safety
and installation of ESS systems.
