Battery Systems Citywide Exam

FDNY W28 Supervision of Mobile Battery Systems (Citywide) Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary fire hazard associated with mobile lithium-ion

battery systems?

• Electrical shock
• Water reactivity
• Thermal runaway
• Corrosion

Rationale: Thermal runaway can rapidly escalate into fire, making it the

main hazard.

• Which document must be available on-site for each mobile battery

system? 1 / 4

• Construction plans
• Manufacturer’s instructions
• Delivery records
• Employee roster

Rationale: Manufacturer instructions detail safe operation, charging,

limits, and emergency procedures.

• Who is permitted to supervise mobile battery systems requiring

supervision under FDNY rules?

• Any employee
• Building superintendent
• W28 Certificate of Fitness holder
• Battery installer

Rationale: Only a W28 C of F holder is authorized to supervise mobile

battery systems.

• What is the minimum required separation from combustibles for mobile

battery systems unless otherwise approved?

• 1 foot
• 3 feet
• 5 feet
• 10 feet

Rationale: FDNY requires a minimum 5-foot clearance from combustibles

to reduce fire exposure. 2 / 4

5. Mobile battery systems must be installed on surfaces that are:

• Carpeted
• Slightly sloped
• Level and stable
• Wooden platforms

Rationale: Stable, level surfaces prevent tipping and ensure system safety.

• What type of extinguisher must be immediately available near mobile

battery systems?

• Class A
• Class K
• Class ABC or Class BC
• Class D only

Rationale: ABC/BC extinguishers are required for energized battery fires.

• When charging a mobile battery system, what is prohibited?
• Charging outdoors
• Charging during daytime
• Use of extension cords
• Use of indicator lights

Rationale: Extension cords pose overload and heating risks; only approved

wiring may be used.

• A mobile battery system must be removed from service if: 3 / 4

• It is over 50% discharged
• It is older than 1 year
• It shows signs of damage or swelling
• It is fully charged

Rationale: Physical damage or swelling indicates high risk of failure.

• Who must be notified in case of fire involving a mobile battery system?
• Building manager only
• OEM technician
• FDNY Bureau of Fire Prevention
• FDNY via 911

Rationale: All fires require immediate notification via 911.

• What is the first action if a battery unit overheats?
• Add water
• Power it down if safe
• Move it to storage
• Disconnect other equipment

Rationale: Shutting down reduces energy flow and heat generation.

• Which sign must be posted at mobile battery system locations?
• No Parking
• No Cell Phones
• Battery System Safety Instructions
• / 4