1. Mechanically formed water supply tee fittings shall be constructed by
A. soldering
B. brazing Correct
C. flaring
D. chemically bonding
Explanation
Brazing joins copper or brass fittings using a filler metal with a melting point above 840°F, creating a strong, leak-proof joint suitable for water supply tees under pressure. Soldering uses lower temperatures and is not permitted for mechanically formed tees in potable water systems due to weaker bonds. Flaring expands the pipe end to fit over a fitting but does not form a tee. Chemically bonding applies to plastics like PVC, not copper or brass water supply systems.
2. What is the purpose of installing a check valve on each zone when piping a multi-zone heating system using multiple circulators
A. To prevent cool water from flowing to other zones
B. To prevent warm water from flowing backwards Correct
C. To improve the efficiency of the air scoop
D. To improve the efficiency of the circulator
Explanation
Check valves allow flow in one direction only, stopping warm water from a running zone from migrating backward through inactive circulators into other zones, which would cause ghost flow and uneven heating. Cool water prevention is not the primary issue—warm water backflow is. Air scoops remove air, not affected by check valves. Circulator efficiency depends on flow design, not check valves.
3. A potable water system is being disinfected with a water-chlorine solution containing 50 parts per million of chlorine. The solution MUST remain in the system for
A. 8 hours
B. 12 hours
C. 24 hours Correct
D. 36 hours
Explanation
At 50 ppm chlorine, the International Plumbing Code requires a minimum contact time of 24 hours to effectively kill bacteria and pathogens throughout the system. 8 or 12 hours is insufficient for full disinfection at this concentration. 36 hours exceeds the minimum requirement and is unnecessary unless specified by local authority.
4. What is the temperature rating for a sprinkler with a blue color code
A. 135 to 170 degrees F
B. 175 to 225 degrees F Correct
C. 250 to 300 degrees F
D. 325 to 375 degrees F
Explanation
NFPA 13 standardizes sprinkler color coding: blue indicates an ordinary temperature rating of 175–225°F, suitable for most commercial and residential environments. 135–170°F is unclassified or ordinary (white or uncolored). 250–300°F is high temperature (green). 325–375°F is very high (orange).
5. Pressure relief valves on hot water tanks MUST open before the water pressure in the tank exceeds
A. 150 psi Correct
B. 180 psi
C. 210 psi
D. 212 psi
Explanation
ASME and IPC require temperature and pressure relief (TPR) valves on water heaters to open at 150 psi to protect the tank from overpressurization before vessel failure. Tanks are tested to 300 psi, but relief must activate well below that. 180, 210, and 212 psi exceed the safe activation threshold.