FDNY S-45 CERTIFICATE OF FITNESS:
SUPERVISION OF CARBON DIOXIDE
FIRE EXTINGUISHING SYSTEMS
QUESTIONS AND VERIFIED ANSWERS
JUST RELEASED
1. What is the primary life safety hazard associated with Carbon Dioxide (CO2) fire
extinguishing systems in occupied spaces?
A. Thermal shock from the cold discharge
B. Toxic chemical reactions with the fire
C. Reduced visibility from the CO2 cloud
D. Asphyxiation due to oxygen displacement
Answer: D
Conceptual Explanation: CO2 extinguishes fire by reducing oxygen levels. In a total
flooding system, the concentration of CO2 is high enough to be fatal to humans through
asphyxiation.
2. According to FDNY standards, how often must high-pressure CO2 cylinders be
hydrostatically tested if they have not been discharged?
A. Every 5 years
,B. Every 12 years
C. Every 10 years
D. Every 15 years
Answer: B
Conceptual Explanation: High-pressure CO2 cylinders must be hydrostatically tested
every 12 years if they have not been discharged; however, if discharged, they must be
tested if it has been more than 5 years since the last test.
3. A high-pressure CO2 cylinder must be refilled or replaced if it shows a loss in net content
(weight) of more than:
A. 5%
B. 10%
C. 15%
D. 20%
Answer: B
Conceptual Explanation: NFPA 12 and FDNY require maintenance action if a cylinder
shows a weight loss exceeding 10% of the stamped full weight.
4. Which device is required to prevent the accidental discharge of CO2 into a protected space
during system maintenance?
A. Manual pull station
, B. Pressure switch
C. Lock-out valve
D. Selector valve
Answer: C
Conceptual Explanation: A lock-out valve is a safety device installed in the discharge
piping that, when closed, prevents CO2 from entering the protected space during
maintenance.
5. What is the minimum duration required for the pre-discharge alarm to sound before CO2 is
released into a total flooding area?
A. 10 seconds
B. 60 seconds
C. 20 seconds or enough time to evacuate
D. 5 minutes
Answer: C
Conceptual Explanation: The pre-discharge delay must be set to allow occupants enough
time to evacuate the space safely before the gas is released.
6. For low-pressure CO2 systems, at what temperature is the CO2 typically maintained within
the refrigerated storage unit?
A. -40 degrees Fahrenheit
SUPERVISION OF CARBON DIOXIDE
FIRE EXTINGUISHING SYSTEMS
QUESTIONS AND VERIFIED ANSWERS
JUST RELEASED
1. What is the primary life safety hazard associated with Carbon Dioxide (CO2) fire
extinguishing systems in occupied spaces?
A. Thermal shock from the cold discharge
B. Toxic chemical reactions with the fire
C. Reduced visibility from the CO2 cloud
D. Asphyxiation due to oxygen displacement
Answer: D
Conceptual Explanation: CO2 extinguishes fire by reducing oxygen levels. In a total
flooding system, the concentration of CO2 is high enough to be fatal to humans through
asphyxiation.
2. According to FDNY standards, how often must high-pressure CO2 cylinders be
hydrostatically tested if they have not been discharged?
A. Every 5 years
,B. Every 12 years
C. Every 10 years
D. Every 15 years
Answer: B
Conceptual Explanation: High-pressure CO2 cylinders must be hydrostatically tested
every 12 years if they have not been discharged; however, if discharged, they must be
tested if it has been more than 5 years since the last test.
3. A high-pressure CO2 cylinder must be refilled or replaced if it shows a loss in net content
(weight) of more than:
A. 5%
B. 10%
C. 15%
D. 20%
Answer: B
Conceptual Explanation: NFPA 12 and FDNY require maintenance action if a cylinder
shows a weight loss exceeding 10% of the stamped full weight.
4. Which device is required to prevent the accidental discharge of CO2 into a protected space
during system maintenance?
A. Manual pull station
, B. Pressure switch
C. Lock-out valve
D. Selector valve
Answer: C
Conceptual Explanation: A lock-out valve is a safety device installed in the discharge
piping that, when closed, prevents CO2 from entering the protected space during
maintenance.
5. What is the minimum duration required for the pre-discharge alarm to sound before CO2 is
released into a total flooding area?
A. 10 seconds
B. 60 seconds
C. 20 seconds or enough time to evacuate
D. 5 minutes
Answer: C
Conceptual Explanation: The pre-discharge delay must be set to allow occupants enough
time to evacuate the space safely before the gas is released.
6. For low-pressure CO2 systems, at what temperature is the CO2 typically maintained within
the refrigerated storage unit?
A. -40 degrees Fahrenheit
