FLSD Fire Alarm Systems 2 — Questions and Answers

Question 1: A duct smoke detector in an HVAC system is designed to:

Activate sprinklers in the ductwork when smoke is detected
Detect smoke in air ducts and shut down the HVAC system to prevent smoke spread (Correct answer)
Monitor air quality for carbon monoxide in occupied areas
Provide early warning of fire in elevator shafts

Correct answer: Detect smoke in air ducts and shut down the HVAC system to prevent smoke spread

Duct smoke detectors sense smoke within HVAC ductwork and automatically shut down the air handling unit to prevent smoke from being distributed throughout the building.

Duct smoke detectors are installed in supply and return air ducts of HVAC systems. When smoke is detected in the airstream, the detector activates, sending a signal to the fire alarm control panel and simultaneously initiating shutdown of the associated air handling unit. This critical function prevents the HVAC system from acting as a smoke distribution network. The FLSD must ensure duct detectors are tested annually (or per the fire safety plan) and that HVAC shutdown is verified during testing.

Question 2: What is the purpose of a manual fire alarm pull station?

To test the fire alarm system without calling FDNY
To allow any person to manually activate the fire alarm system upon discovering a fire (Correct answer)
To silence the fire alarm after FDNY arrives on scene
To communicate with the fire command station in an emergency

Correct answer: To allow any person to manually activate the fire alarm system upon discovering a fire

Manual pull stations allow any building occupant who discovers a fire to immediately activate the building's fire alarm system, alerting all occupants and notifying FDNY via central station monitoring.

Manual pull stations (also called manual alarm boxes or pull boxes) are required at all exit doors and exits in commercial buildings per NYC Fire Code. They must be red, installed at a height accessible to all occupants including wheelchair users, and clearly labeled. When activated, they trigger the building alarm system and transmit a signal to the central monitoring station, which notifies FDNY. The FLSD ensures pull stations are unobstructed, tested during annual inspections, and that all floor wardens know their locations.

Question 3: A 'pre-action' sprinkler system differs from a standard wet pipe system in that it:

Uses dry air instead of water in the pipes
Requires both a detector activation AND a sprinkler head to open before water flows (Correct answer)
Activates all sprinkler heads in a zone simultaneously when a detector triggers
Is used only in parking garages and outdoor areas

Correct answer: Requires both a detector activation AND a sprinkler head to open before water flows

Pre-action systems have a two-step activation: a fire detection device must activate to open a control valve, AND individual sprinkler heads must also open from heat before water flows to that head.

Pre-action sprinkler systems are used in areas sensitive to water damage (computer rooms, archives, museums). They differ from wet pipe (always full of water) and dry pipe (filled with pressurized air) systems. In a pre-action system: (1) a fire detector triggers the pre-action valve to fill the piping with water (like a wet pipe); (2) individual sprinkler heads must still be activated by heat before water flows. This double protection against accidental discharge makes them ideal for high-value areas. Accidentally breaking a sprinkler head will not cause water flow unless the pre-action valve has been opened.

Question 4: The central station monitoring company's role in fire alarm response is to:

Directly extinguish fires remotely via connected suppression systems
Receive alarm signals from the building and immediately notify FDNY (Correct answer)
Test the building's fire alarm system on a quarterly basis
Provide fire safety training to building staff

Correct answer: Receive alarm signals from the building and immediately notify FDNY

The central station monitoring company receives alarm, supervisory, and trouble signals from the building's fire alarm system and immediately transmits fire alarms to FDNY for response.

NYC Fire Code requires high-rise buildings to have their fire alarm systems monitored by a UL-listed central station. The central station operates 24/7, receives signals from the building's fire alarm control panel, and has protocols for each signal type: fire alarms are immediately transmitted to FDNY; supervisory signals (valve closed) are reported to the building; trouble signals are reported to the building for repair. The FLSD should have the central station's contact information and know the building's account number for rapid communication.

Question 5: Heat detectors are preferred over smoke detectors in which type of building area?

Occupied offices and workspaces
Kitchens, cooking areas, and other locations where smoke is normally present (Correct answer)
Stairwells and egress corridors
Computer server rooms and data centers

Correct answer: Kitchens, cooking areas, and other locations where smoke is normally present

Heat detectors are used in kitchens and areas where cooking fumes or steam would cause frequent false alarms with smoke detectors, while still providing fire detection.

Smoke detectors in kitchens and cooking areas would generate constant false alarms from cooking smoke, steam, and vapors. Heat detectors — which activate at a fixed temperature (135°F/57°C typical) or at a rate of rise — are immune to these non-fire conditions. They are installed in kitchens, laundry rooms, and other areas with normal airborne particles. The tradeoff is that heat detectors respond later in fire development than smoke detectors, so they are not used in areas where early warning is critical.

Question 6: When the fire alarm system is placed in test mode for annual inspection, the FLSD must:

Evacuate the building before testing begins
Notify the central station monitoring company so FDNY is not dispatched for test signals (Correct answer)
Disable all fire alarm devices for the duration of the test
Obtain FDNY approval before testing any fire alarm device

Correct answer: Notify the central station monitoring company so FDNY is not dispatched for test signals

Before any fire alarm system testing, the FLSD must notify the central monitoring station so they can place the system in test mode, preventing test signals from dispatching FDNY unnecessarily.

FDNY regulations strictly prohibit causing unnecessary FDNY responses. Before any fire alarm system test, inspection, or maintenance that will generate signals: (1) notify the central monitoring station with the building account number, date/time range of testing, and contact person; (2) the central station places the account in test mode, suppressing signal transmission to FDNY; (3) after testing is complete, notify the central station again to restore normal monitoring; (4) if FDNY does respond to an accidental signal, the FLSD must explain the situation. Failure to notify can result in significant fines.

FLSD Fire Alarm Systems 2

A duct smoke detector in an HVAC system is designed to: