Questions & Answers
1. To
ggle hangers shall be permitted only for the support of pipe
inches or smaller in size under ceilings of hollow tile or metal lath and plaster.
Answer 1 2/2 in. (ref. NFPA 13 2016 Sec. 9.2.1.1.2.
2. While
conducting a flow test, the chosen hydrant should be
Answer As close to the property where the sprinkler system is being installed. (Ref, NFPA 13 Sec. A.24.2.2. or NFPA 291)
3. What formula is used to determine the discharge coefficiant relating pressure
and flow rate?
Answer K = Q / (Square root of P)
4. What best describes a tree system?
Answer Cross mains and the branch lines are not tied together, providing only one path of water flow.
5. Factors that define Occupancy Group Hazard 2 include
Answer
Quantity and combustibility of contents are moderate to high.
Stockpiles of contents with moderate rates of heat release do not exceed 12 ft and stockpiles with high heat release do not
,exceed 8 ft
(Ref NFPA 13 Sec. 5.3.2)
6. Which of the following standards contain reqs. pertaining to the installation
of underground piping?
Answer NFPA 13 & 24 (Both in Chapter 10)
7. Which of the following should you inspect on an extension cord before each
use?
Answer The grounding prong & the insulation for nicks, cuts, or damage
8. indicates a mandatory req. according to NFPA definitions.
Answer Shall.
(Ref. NFPA 13 2016, Sec. 3.2.4.)
9. 100 GPM is flowing through 100' of 1 1/4 in. Sch. 40 pipe. How many feet of 1
1/2 in. pipe will produce the same friction loss?
Answer Assume this is Schedule 40 pipe, C = 120. Use the Hazen-Williams formula to calculate the friction
loss for the 1 ¼ in. pipe and the 1 ½ in. pipe.
For 1 ¼ in. pipe (ID = 1.38)
P friction loss = 4.52 x Q 1.85 c
, 1.85 x d 4.87
P friction loss = 4.52 x 100 1.85
120 1.85 x 1.38 4.87
P friction loss = 0.672 psi/ft
For 1 ½ in. pipe (ID = 1.61)
P friction loss = 4.52 x Q 1.85 c
1.85 x d 4.87
P friction loss = 4.52 x 100 1.85
120 1.85 x 1.61 4.87
P friction loss = 0.317 psi/ft
Step #2
Determine the total friction loss for 100 gpm flowing through 100 ft. of 1 ¼ in. Schedule 40 black steel pipe
100 ft. x 0.672 psi/ft = 67.2 psi