S-13 Water Supply and Pressure Requirements 2 — Questions and Answers
Question 1: When a standpipe system relies solely on a roof gravity tank, what is the minimum acceptable water volume that tank must contain dedicated to standpipe use?
- 2,500 gallons
- 3,500 gallons (Correct answer)
- 5,000 gallons
- 7,500 gallons
Correct answer: 3,500 gallons
NYC Building Code requires a minimum of 3,500 gallons in a gravity tank dedicated exclusively to standpipe use when no other supply is available.
Question 2: What pressure should the standpipe system be maintained at during normal non-fire conditions?
- At 0 psi — dry systems are normal
- At the operating pressure established during the hydraulic design (Correct answer)
- At exactly 100 psi at all outlets
- At street main pressure only
Correct answer: At the operating pressure established during the hydraulic design
Wet standpipe systems are maintained at the system's designed operating pressure at all times so water is immediately available when an outlet is opened.
Question 3: What is the primary function of an automatic air release valve installed at the top of a standpipe riser?
- To release pressure if a hose outlet is opened
- To purge trapped air from the riser to prevent water hammer and ensure full water delivery (Correct answer)
- To activate the fire alarm upon system pressurization
- To limit maximum system pressure
Correct answer: To purge trapped air from the riser to prevent water hammer and ensure full water delivery
Automatic air release valves at riser tops purge trapped air that would otherwise create air pockets reducing flow capacity and causing water hammer when outlets are opened.
Question 4: If a building standpipe water supply pressure drops below the minimum required, what action must the certificate of fitness holder take?
- Notify the building owner only
- Continue monitoring and document the drop in the logbook
- Immediately notify the FDNY and post an out-of-service notice (Correct answer)
- Increase pump speed manually
Correct answer: Immediately notify the FDNY and post an out-of-service notice
A pressure drop below required minimums renders the system impaired; the COF holder must immediately notify FDNY and post out-of-service notices as required by FDNY regulations.
Question 5: What device automatically starts the standpipe fire pump when system pressure falls below a preset level?
- Flow switch
- Pressure switch (pressure transducer) (Correct answer)
- Tamper switch
- Water motor alarm
Correct answer: Pressure switch (pressure transducer)
A pressure switch or pressure transducer monitors standpipe system pressure and automatically starts the fire pump when pressure drops to the preset start pressure setpoint.
Question 6: According to NFPA 14, how many psi of residual pressure is required at the inlet of a standpipe hose connection when flowing the system design demand?
- 65 psi
- 100 psi (Correct answer)
- 75 psi
- 125 psi
Correct answer: 100 psi
NFPA 14 specifies a minimum residual pressure of 100 psi at the inlet to the hydraulically most remote and demanding hose connection while flowing the design demand.
Question 7: A fire pump for a standpipe system must be listed and approved for fire protection service. Which organization's listing is most commonly accepted by FDNY?
- NSF International
- Underwriters Laboratories (UL) (Correct answer)
- American National Standards Institute (ANSI)
- Occupational Safety and Health Administration (OSHA)
Correct answer: Underwriters Laboratories (UL)
Underwriters Laboratories (UL) listing is the primary independent certification FDNY and NYC Building Code require for fire pumps used in standpipe systems.
S-13 Water Supply and Pressure Requirements 2
When a standpipe system relies solely on a roof gravity tank, what is the minimum acceptable water volume that tank must contain dedicated to standpipe use?