FST Sprinkler Systems 5 — Questions and Answers
Question 1: Which sprinkler system configuration is most appropriate for protecting a computer server room where accidental water discharge must be minimized?
- Wet pipe system
- Double-interlock preaction system (Correct answer)
- Deluge system
- Standard dry pipe system
Correct answer: Double-interlock preaction system
A double-interlock preaction system requires both detection and sprinkler activation, minimizing accidental water discharge into sensitive electronic environments.
Question 2: Per NFPA 13, what is the required minimum operating pressure at the most remote sprinkler during a hydraulic calculation?
- 5 psi
- 7 psi
- 10 psi (Correct answer)
- 15 psi
Correct answer: 10 psi
NFPA 13 requires a minimum of 7 psi at any sprinkler for residential systems and at least 7 psi for standard sprinklers, but the common minimum used for standard spray heads is 7 psi; however the exam-standard answer for most sprinklers is 7 psi.
Question 3: A technician is installing a concealed sprinkler head in a finished ceiling. What critical installation error must be avoided?
- Painting the cover plate before installation
- Installing the cover plate before the ceiling drywall is complete
- Mismatching the cover plate temperature rating with the sprinkler temperature rating (Correct answer)
- Using a flat-blade screwdriver to tighten the head
Correct answer: Mismatching the cover plate temperature rating with the sprinkler temperature rating
The cover plate must have the same or lower temperature rating than the sprinkler to ensure the plate drops away before the sprinkler activates.
Question 4: What is the purpose of an antifreeze solution in a sprinkler system protecting an unheated loading dock area?
- To increase the flow rate of water to that zone
- To prevent water in exposed piping from freezing and causing pipe rupture (Correct answer)
- To improve the wetting agent properties of water
- To reduce corrosion in galvanized piping
Correct answer: To prevent water in exposed piping from freezing and causing pipe rupture
Antifreeze systems fill exposed piping with a freeze-resistant solution to prevent ice formation and pipe failure in areas subject to freezing temperatures.
Question 5: Under NFPA 25, when must a 5-year internal pipe inspection be performed on a wet pipe sprinkler system?
- Only when the system fails a flow test
- Every 5 years, or sooner if microbiologically influenced corrosion (MIC) is suspected (Correct answer)
- At the time of the first annual inspection
- Only after a system activation event
Correct answer: Every 5 years, or sooner if microbiologically influenced corrosion (MIC) is suspected
NFPA 25 requires internal pipe inspections on a 5-year cycle, with earlier inspection warranted if MIC or significant corrosion is detected.
Question 6: A large commercial building has sprinkler heads installed in a configuration where alternate heads are staggered in adjacent branch lines. What design pattern is this?
- In-line pattern
- Staggered pattern (Correct answer)
- Clustered pattern
- Central pattern
Correct answer: Staggered pattern
A staggered sprinkler layout offsets heads in adjacent lines to maximize coverage and minimize gaps in the protection area.
Question 7: Which valve type must remain sealed open at all times on a sprinkler system supply main and should be equipped with a supervisory switch connected to the fire alarm system?
- Check valve
- Pressure reducing valve
- Control valve (OS&Y or butterfly type) (Correct answer)
- Drain valve
Correct answer: Control valve (OS&Y or butterfly type)
Control valves such as OS&Y gate valves and butterfly valves must remain open and be monitored by a supervisory switch to alert when they are closed.
FST Sprinkler Systems 5
Which sprinkler system configuration is most appropriate for protecting a computer server room where accidental water discharge must be minimized?