Water Supply and Fire Suppression Flashcards

What is the minimum residual pressure required at the outlet of a fire hydrant during flow testing per NFPA 291?

Answer: 20 psi

NFPA 291 requires a minimum residual pressure of 20 psi at the hydrant outlet during fire flow testing.

A dry-pipe sprinkler system is most appropriate in locations where:

Answer: Pipes may be exposed to freezing temperatures

Dry-pipe systems use pressurized air or nitrogen to keep pipes dry, preventing water from freezing in unheated spaces.

Which type of fire department connection (FDC) fitting is most commonly used in the United States?

Answer: NST (National Standard Thread)

NST (National Standard Thread), also called NH (National Hose), is the most widely used FDC fitting standard in the US.

In a fire suppression water supply system, what does a 'dead-end main' refer to?

Answer: A water main fed from only one direction

A dead-end main is supplied from only one end, limiting flow capacity and creating water quality concerns.

Which valve type is preferred for controlling water flow in fire protection systems because it provides a visual indication of its open or closed position?

Answer: OS&Y (Outside Screw and Yoke) gate valve

OS&Y gate valves expose the stem when open and retract it when closed, providing a clear visual indicator of valve position.

What is the purpose of a pressure-reducing valve (PRV) in a high-rise building's standpipe system?

Answer: Prevent excessive pressure on lower floor hose connections

PRVs limit outlet pressure at lower-floor hose connections where static pressure from elevation head could exceed safe hose handling limits.

Under NFPA 13, what is the required design area for an Ordinary Hazard Group 1 wet-pipe sprinkler system?

Answer: 1,500 sq ft

NFPA 13 requires a design area of 1,500 sq ft for Ordinary Hazard Group 1 wet-pipe sprinkler systems.