CH 13,14,15 exam Flashcards
What is a parapet wall?
a parapet can be an extension of a firewall, a division wall between two buildings or a decorative extension of an exterior wall
What is mechanical ventilation?
A process of removing heat, smoke, and gasses from a fire area by using an exhaust fans, blowers, air- conditioning systems, or smoke ejectors.
What happens when you apply water streams into a structure
Absorbs some of the heat produced by the fire and can help to remove more energy than the fire is creating
What is the 7, 9, 8 ventilation cut best suited for?
This cut is an effective ventilation method for use on large commercial buildings with flat roofs
In ordinary construction, what are exterior walls made of?
Exterior walls are made of noncombustible or limited combustible materials that support the roof and floor assemblies.
What happens when you apply negative pressure?
draw heat, smoke, and fire gasses out of the building
Where should a ladder be placed when breaking a window for ventilation?
Upwind side of the window, tip should be even with the top third of the window
What’s the minimum measurement for ventilation when cutting an opening?
4 foot by 4 foot
What should be in place prior to ventilation?
Two routes of egress, two safe exit routes
What is positive pressure ventilation least suitable for?
This kind of system will not work effectively if the building is not intact
What should be avoided when performing horizontal natural ventilation?
Opening a window on the upwind side first could push the fire into the uninvolved areas of the structure.
Which condition could cause smoke to stratify in a large building?
Sprinkler system activation
What is the stack effect?
The vertical air flow within buildings caused by the temperature- created density differences between the building interior and exterior or between two interior spaces.
What is a concern or hazard in a basement fire?
Fires originating in the basement will quickly involve the floor system. This results in a failure of the floor over the fire and early collapse.
What does sounding the roof mean?
To locate the structural supports before starting to cut.
What is an indication of slow moving smoke?
The smoke is cooler
How should you vent a basement?
Ventilate through exterior windows or doors.
What is plywood sheeting?
Used for roof decking
What is a smoke ejector?
A mechanical device similar to a large fan, used to force heat, smoke, and gasses out of a fire and draw in fresh air
What is horizontal ventilation?
Uses horizontal openings in a structure, such as windows and doors, and can be employed in many situations, particularly in small fires
What is a flashover?
The transition from a fire that is growing by igniting one type of fuel to another to a fire where all of the exposed surfaces have ignited
What is a jet siphon?
Assists in keeping the water level at the maximum capacity in the tank closest to the pumper
What is the trench cut?
A large opening ahead of the fire, removing a section of fuel and letting heated smoke and gases flow out of the building
What is the minimum distance between the center of a fire hydrant outlet, and the ground?
Minimum of 18in from the center of a hose outlet to the finished grade
What is another term for head pressure?
Elevation pressure
How is friction loss proportionate to a length of hose?
Any combination of flow and diameter longer the hose the more friction loss occurs
What is a grid system?
For water mains, it provides water flow to a fire hydrant from two or more directions and establishes multiple paths from the source to each area.
What is a tender?
A truck mounted mobile water supply apparatus
How is a wet barrel hydrant constructed?
Has separate valves to control the flow of water to each outlet
What is static pressure?
The amount of pressure in a system when the water is not moving. (potential energy)
How many gpm can a portable pump deliver?
Portable pumps can deliver as much as 500 gpm
How is the flow or quantity measured?
Volume
What is the flow of water?
Quantity of water flowing through a pipe, hose, or nozzle, measured in volume, usually gallons per minute
What does a hard suction hose do?
Hard rigid hose used to draft water from a static source.
What should be done to avoid a water hammer?
Always open and close fire hydrants valves slowly
Where are dump valves located?
Large opening from the water tank of a mobile water supply apparatus for unloading purposes
Where is the main valve located in a dry barrel hydrant?
Located at the base, several feet underground below the frost line
What are the 4 factors that determine friction loss?
- diameter of hose 2. valves or hose appliances 3. the volume of water traveling through the hose 4. the distance the water travels
When do you use a dump valve?
When unloading a mobile water supply apparatus
Know the color coding system and gpm for hydrants.
Class C 0-499 RED
Class B 500-999 ORANGE
Class A 1,000-1,499 GREEN
Class AA 1,500-up LIGHT BLUE
What is a secondary feeder?
(branch lines) distribute water to a smaller area
What is residual pressure?
The amount of pressure that remains in the system when water is flowing
What does the amount of energy in water mean?
Potential or kinetic energy
What is hydraulics?
Deals with the properties of energy, pressure, and water flow as related to fire suppression
What is elevation pressure?
The difference in height between the water in the tank and the underground delivery pipes.
How do you calculate how much a hose weighs when it’s charged?
What is a soft sleeve hose used for?
Allows as much water to flow from the suction side to the fire pump as possible.
What’s the difference between fog nozzles and smooth bore nozzles?
Smooth Bore nozzles - Produce a solid stream or column of water
Fog Stream nozzles- can be adjusted to produce a straight stream or to separate the water into droplets for fog streams
What happens to hoses during annual testing?
The hose is inspected and sorted based on service test pressures required by NFPA Standards. 200 psi for supply and 300 for attack lines.
What are the flows and gpms of attack hoses?
120- 180 GPM
What is the difference between a doughnut hose roll and a straight hose roll?
Donut - Both couplings are on the outside of the roll
Straight - male coupling on inside roll, female on outside roll
What is a booster hose?
1-Inch in diameter usually carried on a hose reel that carries 150 ft or 200 ft of hard rubber hose. Can be operated easily by one person but has limited flow.
What is considered a large diameter hose?
3 ½ inches or more.
What are the flows for a handline, master stream, and smooth bore?
Master stream: 350 - 1500 GPM
Handline: 60 - 350 GPM
Smooth bore: 50 PSI
What does coupling mean?
Used to connect or couple individual hose lines.
Why is a water thief different from a wye?
A water thief has an outlet for a 2.5in line
What is the nozzle pressure for a fog nozzle?
100 psi
What is a siamese appliance?
Combines two or more hose lines into one.
How should you clean a dirty fire hose?
Cool water, mild detergent, and a soft brush.
What hose diameter can be used in both a supply line and an attack line?
The 2 ½ hose can be used as either attack hose or supply hose.
How do you use a hose clamp?
Used to temporarily stop the flow of water in a hose line.
What are the advantages of a smooth bore nozzle?
They operate at a lower pressure and have more reach.
What are the advantages of an automatic adjusting fog nozzle?
Can deliver a wide range of flows.
Which attack line is appropriate for a dumpster fire?
Booster hose
According to tests conducted by UL, in order for ventilation to improve interior conditions, what must occur?
Ventilation must be coordinated with the application of water as close to the fire as possible
How can recirculation be eliminated during smoke ejection?
Completely block the opening around the fan
What is the greatest risk to firefighters performing vertical ventilation?
Roof collapse
Where is water directed during hydraulic ventilation?
Out a window or door
What is the disadvantage of positive pressure fans?
They can spread fire if used improperly
Which problem can be caused by using doorways as ventilation openings?
It compromises personnel entry and exit
Which item greatly increases risk during vertical ventilation operations?
Lightweight construction components
Which statement about the operation of HVAC equipment during fire ventilation operations is correct?
Some HVAC systems can be used for clearing smoke
Which structural component is composed of relatively small and lightweight components arranged in a series of triangles?
Truss
Which type of building is the most prone to the stack effect?
High rise
A dry hydrant provides access to a _____.
Static water source
An object in motion possesses which kind of energy as a result of that motion?
Kinetic
Firefighters may need to hold on to the ____ while filling a self expanding portable tank.
Collar
How close must a fire engine get to a static water source to be able to draft directly from it through a hard suction hose?
20 ft(6m)
How many gallons per minute can a tanker shuttle operation deliver without interruption?
Several hundred
In general, mobile water supply apparatus (tankers) carry _____ of water.
1000 - 3500 gal (3785 to 13,249 L)
Pressure in a water distribution system during average consumption is _____ pressure.
Normal operating
What is the maximum capacity of typical portable water tanks?
5000 gal (18,927 L)
What is the realistic minimum usable residual pressure from a water distribution system for firefighting operations?
20psi (138 kPa)
When water is motionless, which kind of energy does it have?
Potential
The NFPA recommends that a pumper carry a minimum of ____ of supply hose.
800 ft (242 m)
The two firefighter stiff arm method is used to:
Uncouple hose
Which coupling goes on the inside of a straight hose roll?
Male
Which device splits one hose stream into two hose streams?
Wye
Which is a function of a hose liner?
Reduce friction loss
Which is the best description of a hose jacket device?
Split metal cylinder
Which is the correct tool to tighten a hard suction hose connection?
Rubber mallet
Which is used to carry a self locking twin doughnut hose roll?
A loop of hose
Which type of valve is opened or closed by rotating a handle a quarter turn?
Butterfly
Which type of wrench is used to tighten and loosen couplings?
Spanner
