Piping Arrangements Flashcards
Explain how each sprinkler system component works and how they all tie together.
The system riser connects the underground piping and is what initially supplies the entire sprinkler system network. The feed main is a transfer main that is supplied by the riser to feed another area of the building. The cross main provides water to the branch lines from the system riser. Other components include branch lines, drops, sprigs(candles).
What are the 3 different categories of piping systems?
tree system, grid system, and loop system.
How does a tree system work?
Water goes from the system riser to the cross and feed main piping to the branch lines, and finally to the sprinkler head. Water only ever comes from one direction.
How does a grid system work?
Grid systems have parallel mains that are connected through branch lines. Allows water from either direction to supply the sprinkler head. Makes design easier.
Can you use a hydraulically calculated grid design for a dry system?
No, because too much air can remain trapped in the grid system. Trapped air can slow down the water. The use of relief valves is necessary for pressure build-up in grid systems.
What is a loop system?
A loop system is where multiple cross mains are tied together but the branch lines aren’t like in a grid system.
Compare a tree system to loop and grid systems.
Loop systems could be sized smaller with hydraulic calculations, but were still on the expensive side; alternatively, grid and loop systems could achieve better hydraulic calculations and have the benefit of more than one path of flow.
How many major classifications of fire protection systems are there?
- The 4 most common are wet, dry, pre-action, deluge systems.
What are the three types of pre-action sprinkler systems?
Single interlock system - detection device
Non-interlock system - either detection device or sprinklers
double interlock system - Needs both detection devices and sprinklers to trigger.
What is a deluge system?
A deluge system has open sprinkler heads. When the valve opens water discharges from every sprinkler head connected to that system.
What is the largest hose that can be used for hand hose connection?
1 1/2 inch hose. Hose connections cannot exceed 100 psi or else a pressure regulating device will have to be installed. 100 psi for residual pressures. 175 psi for static pressures.
Are hose connections allowed on dry systems?
Not usually, because inexperienced people may trip the system opening the valve expecting water to come out immediately. It is the AHJ decision though.
What are the other 5 less common fire protection systems?
Exterior fire exposure sprinkler systems, foam systems, carbon dioxide (C02) and other gas extinguishing systems, dry chemical, and water mist systems.
What kind of system would you most commonly see in an aviation hanger?
Foam-water deluge sprinkler systems. Normally used in special hazard occupancies with high challenge fires.
What is the most commonly used gas extinguishing system?
CO2 system.
What are the four gas extinguishing system?
CO2, FM 200, inergen, and sapphire.
What gas extinguishing agent has a more environmentally friendly composition?
FM-200 systems. Total flooding fire suppression system
What are the three types of systems relating to the distribution of gas extinguishing systems?
Local application system - discharges directly on burning material
Total flooding system - discharges into enclosed space or enclosure around a hazard and fills to the proper concentration.
Hand hose line system - hose and nozzle assembly.
Inergen is a mix of what elements?
nitrogen, argon, and carbon dioxide. Inergen is a total flooding system. Protects against class A, B and C
Sapphire systems extinguishing agent is stored in a ___ form that is pressurized with ____. It turns into a ___ when discharged.
Stored in a liquid form. Pressurized with nitrogen. Turns into a gas when discharged. It is a total flooding system.
What are the three types of dry chemicals?
Sodium bicarbonate, potassium bicarbonate, ammonium phosphate
What are the four types of systems through which dry chemicals can be distributed?
Total flooding systems, local application systems, hand hose line systems, and a combination of local application and total flooding.
Dry chemicals are effective against what classes of fires?
flammable liquid and electrical. B and C
What are the three mechanisms a water mist system uses to fight fires?
cooling, radiant heat blocking and local oxygen inerting. They’re effective against mot fires and are considered a clean agent