, Question 1
A warehouse storing Class IV commodities in racks 20 ft high requires a
design density of 0.45 gpm/ft² over 2,500 ft². If the ceiling height is 30 ft and
the sprinkler operating pressure is 50 psi, what is the minimum required flow
per sprinkler for a standard spray sprinkler with K-factor 5.6?
A. 39.6 gpm
B. 50.0 gpm
C. 56.0 gpm
D. 70.7 gpm
Correct Answer: A - 39.6 gpm
RATIONALE
Flow per sprinkler is calculated as Q = KP, where K=5.6 and P=50 psi.
Thus Q = 5.6 × 50 5.6 × 7.071 = 39.6 gpm. The design density and
area are used for total demand, not individual sprinkler flow.
Question 2
In a light hazard occupancy, the maximum sprinkler protection area per
sprinkler is 225 ft² for a hydraulically calculated system. If the sprinklers are
spaced 15 ft apart on branch lines, what is the maximum allowable spacing
between branch lines?
A. 10 ft
B. 12 ft
C. 15 ft
D. 20 ft
Correct Answer: C - 15 ft
Page 2
, RATIONALE
The area per sprinkler is the product of branch line spacing and
sprinkler spacing along the branch line. Thus, branch line spacing =
225 ft² / 15 ft = 15 ft. NFPA 13 also limits maximum spacing to 15 ft
for light hazard.
Question 3
A fire pump is installed to boost water supply for a sprinkler system. The pump
has a rated capacity of 1000 gpm at 100 psi. If the pump is operating at 150%
of rated capacity, what is the approximate discharge pressure according to the
pump curve?
A. 65 psi
B. 70 psi
C. 75 psi
D. 80 psi
Correct Answer: A - 65 psi
RATIONALE
NFPA 20 requires that at 150% of rated capacity, the pump discharge
pressure is not less than 65% of the rated pressure. 65% of 100 psi =
65 psi. The pump curve typically shows a pressure of about 65% of
rated at 150% flow.
Question 4
During a hydraulic calculation, the friction loss in a 2-inch schedule 40 steel
pipe with a flow of 500 gpm is 0.05 psi/ft. If the pipe length is 100 ft and there
are two 90-degree elbows (equivalent length 5 ft each), what is the total friction
loss?
A. 5.0 psi
B. 5.5 psi
C. 6.0 psi
Page 3
, D. 6.5 psi
Correct Answer: B - 5.5 psi
RATIONALE
Total equivalent length = 100 ft + 2×5 ft = 110 ft. Friction loss = 0.05
psi/ft × 110 ft = 5.5 psi. Elbows add equivalent length to the pipe run.
Question 5
A sprinkler system is designed for an ordinary hazard Group 2 occupancy. The
water supply curve is relatively flat. Which of the following adjustments to the
design is most appropriate to ensure adequate safety margin?
A. Increase the design density by 10%
B. Increase the area of operation by 20%
C. Add a fire pump to boost pressure
D. Reduce sprinkler spacing to increase flow per sprinkler
Correct Answer: C - Add a fire pump to boost pressure
RATIONALE
A flat water supply curve indicates that pressure drops significantly
with increased flow. Adding a fire pump boosts pressure, ensuring the
system meets demand. Increasing density or area would increase
demand, worsening the margin. Reducing spacing increases flow per
sprinkler but may not address pressure.
Question 6
In a sprinkler system, the inspector's test connection is used to verify that the
alarm initiates within a specified time. According to NFPA 13, what is the
maximum time allowed for water to flow from the inspector's test connection
to the alarm?
A. 30 seconds
B. 60 seconds
Page 4
A warehouse storing Class IV commodities in racks 20 ft high requires a
design density of 0.45 gpm/ft² over 2,500 ft². If the ceiling height is 30 ft and
the sprinkler operating pressure is 50 psi, what is the minimum required flow
per sprinkler for a standard spray sprinkler with K-factor 5.6?
A. 39.6 gpm
B. 50.0 gpm
C. 56.0 gpm
D. 70.7 gpm
Correct Answer: A - 39.6 gpm
RATIONALE
Flow per sprinkler is calculated as Q = KP, where K=5.6 and P=50 psi.
Thus Q = 5.6 × 50 5.6 × 7.071 = 39.6 gpm. The design density and
area are used for total demand, not individual sprinkler flow.
Question 2
In a light hazard occupancy, the maximum sprinkler protection area per
sprinkler is 225 ft² for a hydraulically calculated system. If the sprinklers are
spaced 15 ft apart on branch lines, what is the maximum allowable spacing
between branch lines?
A. 10 ft
B. 12 ft
C. 15 ft
D. 20 ft
Correct Answer: C - 15 ft
Page 2
, RATIONALE
The area per sprinkler is the product of branch line spacing and
sprinkler spacing along the branch line. Thus, branch line spacing =
225 ft² / 15 ft = 15 ft. NFPA 13 also limits maximum spacing to 15 ft
for light hazard.
Question 3
A fire pump is installed to boost water supply for a sprinkler system. The pump
has a rated capacity of 1000 gpm at 100 psi. If the pump is operating at 150%
of rated capacity, what is the approximate discharge pressure according to the
pump curve?
A. 65 psi
B. 70 psi
C. 75 psi
D. 80 psi
Correct Answer: A - 65 psi
RATIONALE
NFPA 20 requires that at 150% of rated capacity, the pump discharge
pressure is not less than 65% of the rated pressure. 65% of 100 psi =
65 psi. The pump curve typically shows a pressure of about 65% of
rated at 150% flow.
Question 4
During a hydraulic calculation, the friction loss in a 2-inch schedule 40 steel
pipe with a flow of 500 gpm is 0.05 psi/ft. If the pipe length is 100 ft and there
are two 90-degree elbows (equivalent length 5 ft each), what is the total friction
loss?
A. 5.0 psi
B. 5.5 psi
C. 6.0 psi
Page 3
, D. 6.5 psi
Correct Answer: B - 5.5 psi
RATIONALE
Total equivalent length = 100 ft + 2×5 ft = 110 ft. Friction loss = 0.05
psi/ft × 110 ft = 5.5 psi. Elbows add equivalent length to the pipe run.
Question 5
A sprinkler system is designed for an ordinary hazard Group 2 occupancy. The
water supply curve is relatively flat. Which of the following adjustments to the
design is most appropriate to ensure adequate safety margin?
A. Increase the design density by 10%
B. Increase the area of operation by 20%
C. Add a fire pump to boost pressure
D. Reduce sprinkler spacing to increase flow per sprinkler
Correct Answer: C - Add a fire pump to boost pressure
RATIONALE
A flat water supply curve indicates that pressure drops significantly
with increased flow. Adding a fire pump boosts pressure, ensuring the
system meets demand. Increasing density or area would increase
demand, worsening the margin. Reducing spacing increases flow per
sprinkler but may not address pressure.
Question 6
In a sprinkler system, the inspector's test connection is used to verify that the
alarm initiates within a specified time. According to NFPA 13, what is the
maximum time allowed for water to flow from the inspector's test connection
to the alarm?
A. 30 seconds
B. 60 seconds
Page 4
