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fire science chapter 17 fire control

Terms in this set (68)

the IC or supervisor will decide where and from what direction to make entry for an interior fire attack. before entering a burning building, every member of the crew should perform a quick size-up and maintain a high level of situational awareness.
interior fire attack crews advancing hoselines must carry tools and equipment needed to open interior doors, check concealed spaces for fire extension, or to make an emergency exit. before entering the building, the FF assigned to the nozzle should open the nozzle fully to ensure adequate flow, check the pattern setting, and bleed air from the hoseline. *do not open the door until you have a charged hoseline and are ready to control the conditions encountered.

when an interior attack is going to be made on a structure fire, FFs should wait in a safe area near the building entrance. from this location extinguish visible fires around entry or exit points. when the attack crew moves to the building entrance, they should stay low and out of the doorway while the door is forced open. check the door for heat before opening with the back of a gloved hand, a TI, or applying a small amount of water spray to the surface of the door.

if the fire is ventilation controlled, cooling the hot gases overhead can reduce the risk of ignition potentially leading to flashover and provide a safer operating environment.

you must observe the smoke movement and air flow when the door is opened: fast air movement in at the bottom and smoke moving out at the top indicates an active fire. with the attack hoseline in place, open the door slightly, apply water to the hot gas layer, and wait 5-10 seconds to observe any reactions before entering the structure.

FFs must maintain control of the door as it is opened. place a rope hose or utility strap over the doorknob so that it can be quickly pulled closed if necessary. once the door is open and entry is made, chock the door to prevent it from closing on the hoseline.

because wind can cause unpredictable changes to the fire, you should attack with the wind at your back.
residential basements may be totally unfinished, partially unfinished, or completely finished. in an unfinished basement, the floor joists are exposed to the fire and will fail sooner than a ceiling protected with drywall.
factors that contribute to basement fires include:
-fuel loading, especially on the floor above the basement
-age of exposed joists
-hidden paths for fire in walls and ducts that could be exposed in basements
-use of lightweight construction materials that are susceptible to rapid collapse.

basement fires weaken the main floor of a structure creating a constant danger of structural collapse. during initial fire fighting operations, sounding the floor and using a thermal imager have been used to determine if the floor is safe to walk on. when the fire is extinguished, a visual inspection of the floor joists should be made before personnel are permitted to work on the first floor.

accessing the basement is also very dangerous. interior and exterior enclosed stairwells act as a flow path for smoke, flames and heat red gases, much like a chimney. attempting to advance an attack hoseline down an enclosed stairwell may be the only avenue available but it exposed FFs to tremendous hazards. if the first floor is determined to be unsafe, an exterior attack can be made through basement windows. if any openings into the basement exist, use it to apply water to the area before ventilating or entering the first floor. a penetrating or cellar nozzle can also be used if it can be installed without placing personnel on the weakened floor.
in an interior stairwell attack, it is critical that you have enough hoseline to reach the base of the stairs and an additional 6 to 8ft at the bottom to get through the door and out of the narrow area created by the doorway and stairwell.
basement fires are hot and opening a vent point to allow oxygen to enter is going to create more problems
*fire department personnel are not responsible for turning utilities back on and should not attempt to do so.

the sources of electricity are usually a commercial power company or an alternative power source in the form of solar panels, wind generators, or fuel-powered generators. in any case, electric service must be disconnected when there is a fire in the structure.

-commercial power supply: electric lines that may be aboveground or buried connect structures to the main power grid. if the lines are aboveground, they will run from the power company pole to a weather head and service mast which will extend down the side of the house to the electric meter box and shutoff. when shutting off the power, pull the handle on the side of the meter box down. in a residential structure, you can shut off the main circuit breakers and cut power to the structure; however, the meter box is the only location that will shut off power to the entire structure. *never touch a steel service mast
electrical power to the entire building should not be shut off until ordered because electrical power is necessary to operate elevators, air-handling equipment, and other essential systems in all types of occupancies.
both high voltage and low voltage systems may be found in many buildings. if power is shut off to the entire building or any device in it, the main power switch should be locked out and tagged out to prevent it from being turned back on before it is safe to do so.

when alternative sources of energy are present, such as solar power or turbines, removing the meter or turning off the master switch may not turn off the power entirely. solar panels generate current whenever there is a light source and are always energized. for wind turbines, even if the power is turned off at the meter box, the power line from the turbine to the meter will remain energized.
many houses, manufactured homes, businesses, and industrial properties use natural gas or LPG for cooking, heating, or industrial processes.

natural gas: in its pure form, natural gas is methane, a colorless odorless gas; however, mercaptan is added to give it the smell of rotten eggs. natural gas is lighter than air and so it tends to rise and diffuse in the open. while it is nontoxic, it is classified as an asphyxiant because it may displace normal breathing air in a confined space.
when ordered, the natural gas supply to a structure must be shut off at the meter. the shutoff is an inline valve located on the owner supply side of the meter; that is, between the distribution system and the meter. it is the responsibility of the utility company, not the FD, to turn gas utilities back on.
caution: natural gas that leaks underground in wet soil can lose its odorant and become difficult to detect without instruments

liquified petroleum gas (LPG): refers to fuel gases stored in a liquid state under pressure. butane and propane are the two main gases in this category, although propane is the most popular. like methane, propane is colorless and odorless but mercaptan is added. also, it is nontoxic but is classified as an asphyxiant.
LPG is heavier than air and so will sink to the lowest point possible. the gas is explosive in concentrations of 1.5-10%. it is stored in cylinders and tanks near its point of use. the tank or cylinder is then connected by steel piping and copper tubing to the appliances the gas serves. an LPG leak will produce a visible cloud of vapor that hugs the ground. a fog stream of at least 100gpm can be used to dissipate this cloud of unburned gas.
the first arriving fire officer or FF must establish command. generally, there are three initial command options that should be relayed when command is taken.
1. nothing showing - when the problem is not obvious, the officer or FF should assume command of the incident and broadcast on the radio that "nothing is showing". that person should direct the other responding units to assume predetermined positions at the scene to allow for a maximum of deployment flexibility. the officer/FF then accompanies unit personnel on an investigation of the situation and maintains command using a portable radio

2. fast-attack - when the officer of FFs direct involvement is necessary for the unit to take immediate action to save a life or stabilize the situation, they should take command and announce that the unit is initiating a fast attack. personnel will continue the fast attack, which usually only lasts a short time, until one of the following situations occurs:
-incident is stabilized
-incident is not stabilized, but the officer/FF must withdraw to establish a formal incident command post (ICP)
-command is transferred

3. name the incident and establish the ICP - officer or FF should assume command by naming the incident and designating an ICP, giving an initial report on the conditions and requesting the additional resources needed.
-combat command: office/FF performs multiple tasks such as serving as IC, developing incident action plan (IAP), and performing active tasks such as advancing hoseline
-formal command: involves the company officer remaining at the mobile radio in the apparatus, assigning tasks to unit personnel, communicating with other responding units, and expanding the NIMS-ICS as needed by the complexity of the incident. in addition, the officer/FF must decide how to deploy the remainder of the unit.
even though water alone is an ineffective extinguishing agent for class B fires, it can be used in various ways to safely control them. remember that hydrocarbons (gasoline, kerosene, and other petroleum products) do not mix with water, and polar solvents (alcohols, lacquers) do mix with water.

-cooling agent: water can be used as a cooling agent to control class B fires and to protect exposures. water without foam additives is not particularly effective on lighter petroleum distillates (such as gasoline or kerosene) or alcohols. however, water applied as droplets in sufficient quantities can absorb the heat from fires in heavier oils such as raw crude and extinguish the fires.

-mechanical tool: water from hoselines can be used to move class B fuels to areas where they can safely burn or where ignition sources are more easily controlled. class B fuels must never be flushed down storm drains or into sewers. use appropriate fog patterns for protection from radiant heat and to prevent "plunging" the stream into the liquid. plunging a stream into burning flammable liquids causes increased production of flammable vapors and greatly increases fire intensity. slowly move the stream from side to side and "sweep" the fuel or fire to the desired location.

-crew protection: fog stream patterns can be used as crew protection when advancing to shut off liquid or gas control valves. although one hoseline can be used for crew protection, two lines with a backup line are preferred for fire control and safety.

when pressure vessels containing flammable/combustible liquids or compressed gases are exposed to flame impingement, apply solid streams from their maximum effective reach until relief valves close. a minimum of 500gpm must be applied at each point of flame impingement