Chapter 7 Fire Protection Systems Flashcards
If the building or area that is on fire is equipped with an automatic fire suppression system, the primary tactic is to __________________.
support the system and let it do its job.
The fire death rate in homes protected by a WET pipe sprinkler system is ________ lower than in non-sprinkler-protected homes.
83%
The fire damage in homes with wet pipe sprinkler systems is ______ lower than in nonsprinkler-protected homes.
69%
The primary purpose of a sprinkler system in a home is to do what?
Allow additional escape time
What are three principal causes of unsatisfactory sprinkler performance?
- A closed valve in the water supply line
- The delivery of an inadequate water supply to the sprinkler system
- Occupancy changes that render the installed system unsuitable.
What is the type of sprinkler system most often encountered as well as most reliable in fire suppression?
The wet pipe spinkler
The dry pipe system is used in areas that might be subjected to _______________.
Freezing temperatures
A preaction sprinkler system is also filled with air that may or may not be under pressure. The one difference is that a _________________________;
A sensing device, such as a smoke or heat detector, opens a valve, flooding the piping with water.
The most common operational error at properties protected by automatic sprinkler systems is ________________.
shutting down the system prematurely
Most departments provide a pressure of _______ to the FDCs.
150psi
Many sprinkler systems are designed and tested to a maximum of ______.
175psi
Potential problems needing to be addressed when using large-diameter hose to supply a sprinkler or standpipe system.
- The weight of the hose and water bearing on the intake is significant
- Kinks are more likely
- The unisex connection can accidentally disconnect
- There is no redundancy
- Standard large-diameter hose is generally tested at a lower pressure than 2 1/2 or 3 inch hose
- Large-diameter hose is typically tested to 200 psi.
Male threads on an FDC are commonly used to ____________ or as a wall hydrant.
test the system (test headers)
Deluge systems often protect what?
Highly flammable materials or other high hazard materials.
Many facilities that are protected by deluge systems are such that total loss has already occurred in the area of operation. The deluge system is merely for what?
Preventing extension.
NFPA 14 lists the 6 types of standpipe systems.
- Automatic dry
- Automatic wet - this is the most common type
- Semiautomatic dry
- Manual dry
- Manual wet
- Combined system
System has pressurized air/nitrogen but is connected to a water supply that automatically fills the pipes when a discharge is opened.
Automatic Dry
The piping is filled with water and water is provided when a discharge is opened.
Automatic Wet
In this system, a dry standpipe admits water into the system piping upon activation of a remote-control device located at a hose connection.
Semiautomatic Dry
System is filled with air and does not have a water supply; relies entirely on water provided by the FDC.
Manual Dry
System is filled with water connected to a water supply that maintains water in the system, but it is not capable of providing water for FF use unless supplied by the FDC.
Manual Wet
This system supplies both sprinklers and standpipes.
Combined System
Three classes of standpipes?
Class I, Class II, Class III
Class I standpipe
Provides 2 1/2” hose connection to suppluy water for FD use
Class II standpipe
Provides 1 1/2” hose connections and hose stations for use primarily by trained personnel
Class III standpipe
Provides 1 1/2” hose for trained personnel and 2 1/2” hose connections to supply a larger volume of water for use by FDs.
Older codes generally specify _______ at the standpipe outlet, whereas modern codes usually require ______.
65 psi / 100 psi
Preincident plan information about the standpipe should include:
- Standpipe location(s)
- Location of FDC and hydrant closest to the FDC
- Special hydraulic considerations
- Location of fire pump and valves
- Maximum and minimum pressures
- Pressure at standpipe outlets
- Maximum flow
Some FDCs have more than two intakes. In most cases, this indicates what?
That a flow greater than 500 gallons per minute may be required. (It is best to supply all intakes to the system being used)
Pressure requirements for a standpipe system include:
- Elevation loss
- Friction Loss in hose
- Friction loss in standpipe
- Nozzle pressure
In most operations, an allowance of _____________ of friction loss is adequate for the standpipe system piping.
10 - 15 psi
The laws of hydraulics tell us that there is __________ of backpressure for every 1 foot of elevation.
0.434 psi
Different extinguishing agents
- Foam
- Halon
- Carbon Dioxide
- Dry chemical
- Other inerting systems
What is the number one defense against flammable liquid fires but is nearly useless on pressurized liquids or gases?
Foam
Will foam suppress a 3-dimensional fire?
No.
What increases the effectiveness of water and adheres well to exposed structures?
Class A Foam
What are the two types of automatic carbon dioxide systems?
- Total flooding
- Local application
What is the range of carbon dioxide concentrations if it is being used to suppress a fire?
34-75%
Halon is not considered toxic, but the products of decomposition are harmful to humans and might damage some electronic components.
Products of Decomposition: Hydrogen fluoride, hydrogen chloride, and hydrogen bromide)
Dry chemical systems are used in many other applications such as dip tanks and gasoline dispensing facilities. However _______________ are the predominant application.
Kitchen hood systems
