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Posts tagged ‘fire’

A to Z: Y is for Wye

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The “wye” is a connection that will split one hose into two different lines. These might be needed for long driveways where the fire engine can’t maneuver, houses set far back, or a multi-family structure with limited access. One type of these is referred to as a “water thief”, or a gated wye. This can be used to allow water to only go through one side of the connection or both at the same time. These usually have a 2 1/2 inch inlet and 2 1/2 inch outlets.

There is also the siamese coupling that will turn two smaller lines into one hose line. This is commonly used to avoid the loss of friction in long hose lays. It also adds additional lines on the fireground. These usually have 2 or 3 “female” connections coming into the appliance and one “male” connection for the discharge.

There’s also the Z-adapter, which is for connecting supplemental pumps into long hose lines. These are usually adapted from two gated wyes and a double female connection. Or a siamese may be connected to one outlet of the gated wye.

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A to Z: W is for Wildfire

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I was going to talk about Working fire today, but I already went into that a bit on Friday. So, instead I decided to write about wildfires. A wildfire is an uncontrolled fire in an area with combustible vegetation. There are three types of wildfires: bushfire(in Australia), Forest fire, or a brush fire. Around here, we don’t have many forest fires, although that’s probably what most people think of when they hear wildfire. We do have a lot of calls for brush fires during the summer however. A lot of times, these can be put out quickly, but some departments do have a truck dedicated to these outside fires. These are mostly pickup trucks that may have had the bed refitted to haul hose and other equipment needed.

By Kern County Fire Department [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)%5D, via Wikimedia Commons

Forest fires can be the most dangerous. And the wildland firefighters have more to contend with than just the flames. Most of these fires occur during the hotter months, so there’s already heat added to that of the fire. So, they can face heat stress, fatigue(as these fires aren’t easily or quickly put out), and even animal bites. The protective gear is heavy and can lead to heat exhaustion. Also wildfire behavior can be unpredictable. It only takes a shift of wind forĀ  the path of the fire to change. This can end up trapping firefighters who thought they were containing it.

By Bureau of Land Management [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)%5D, via Wikimedia Commons

There are some different methods of suppressing these fires. One is by dropping water and fire retardants from planes and helicopters. Also firelines can be made by digging trenches, cutting back trees, and also backburning. This seems counterintuitive, as it means setting fires to suppress a fire. But, these fires are smaller, controlled burns. However, since these are controlled, they can often be extinguished quickly and then there is no more fuel for the main fire to burn. Sometimes the two fires meet, though, but once again with nothing left to fuel it, the main fire can be more easily suppressed.

By U.S. Department of Agriculture (Flickr: 20120628-F-JQ435-046) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0) or Public domain], via Wikimedia Commons

Of course, once the fire is out, the danger isn’t over. These large fires often leaves areas smoldering, even if there aren’t flames and this poses a risk of re-ignition. So, the burn area needs to be completely cooled. And there’s still more work to be done after that. All the things done to put the fire out, along with the loss of vegetation, can cause soil erosion. Which can lead to more problems. To counteract this, waterbars can be built. Also, new plants and debris can be added to exposed soil to limit the damage.

 

Charred forest following a fire in the North Cascades, Washington. Ground vegetation is just beginning to return. Originally uploaded to the English Project by Bcasterline

 

 

A to Z: U is for Under Control

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When a fire is said to be “under control”, it means it’s no longer spreading and is currently contained. It does not mean that the fire is out yet. This is just one evaluation, or size-up, that can be made of a fire. Once it’s under control, that’s when they would move on to overhaul operations.

Some other stages a fire may be in during size-up include:

Incipient Stage: This is the beginning of a fire. It’s still small and may simply be put out with a handheld extinguisher.

“Smoke Showing”: Maybe not an “official” size-up term, but this means smoke can be seen from outside the structure. The fire may still be small, but it’s likely on the way to growing into more.

Working Fire: This has moved past the incipient stage and may be considered a “real fire”. It is considered “working” when it’s in the process of being suppressed. It will probably not be able to be put out by a single fire company. Instead, departments that are usually part of a pre-planned mutual aid may be called in, either to bring more engines or trucks, or to stand by in case they are needed.

Well Involved/Fully Involved: Fire, heat, and smoke are so wide-spread that interior access may be delayed until fire streams can be applied.

A to Z: R is for Rapid Intervention

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A Rapid Intervention Team or Crew(also referred to as RIT or RIC) is a team of two or more firefighters whose job it is to rescue any firefighters in distress. Some of the standards for the RIT team are that at least two fully equipped firefighters(full turnout gear as well as SCBA and any other tools needed) will be standing by whenever crew members enter a hazardous environment.

This is the basis of the Two In, Two Out policy. Two firefighters should go in together. using a sort of buddy system, they maintain voice or visual contact at all time. if one needs to leave, they both need to. One shouldn’t stay behind. Of the two standing outside, one should be dedicated to accounting for the two firefighters inside and initiate a rescue if one of the interior firefighters is in distress. At times, another two would come on to stand by if these two are required to go in. Of course, not all departments will have enough crew members to make this possible. Sometimes there will be RIT crews at every entry point to a structure, but again, this will depend on staffing among other issues.

 

A to Z: Q is for Quad or Quint

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Both the Quad and Quint are trucks that combine functions of different trucks. The only real difference is how many functions they can perform.

The Quad combines four functions into one truck. It has a water tank and pumping capabilities and carries ground ladders and hoses. These go back as far as 1925 but are losing popularity now. Most departments are going to a Quint.

By Bidgee (Own work) [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)%5D, via Wikimedia Commons

As you may have figured out, The Quint combines five functions into one truck. As well as the different functions combined into a quad, the Quint also features an aerial ladder. There may be many reasons for going to the Quint. But, one of the main ones is staff shortages. This is especially true for volunteer departments(which I’ll be going into more about on Saturday). The optimal number for a safe and effective crew on a truck or engine is at least four firefighters. With staff shortages(and a declining number of volunteers), it’s easier to outfit a quint with a full crew than a truck and an engine.

By Joedamadman (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)%5D, via Wikimedia Commons

A to Z: P is for PASS Device

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A PASS device, or Personal Alert Safety System, is a device used by firefighters when entering a hazardous environment(also know as IDLH – Immediately Dangerous to Life or Health), particularly a burning building. This will emit a loud tone to let others nearby know a firefighter may be in distress.

This device is usually used in conjunction with a self-contained breathing apparatus(which I’ll have more on next week). The small battery powered device is attached to the harness of the airpack where it can be easily reached when needed. It can either be activated manually, when a firefighter realizes they are in trouble, or it will engage automatically if it doesn’t detect motion within 15-30 seconds. Older models could only be manually activated, but with a firefighter incapacitated, they would not be able to do that.

Most PASS devices have a muted warning, alerting the firefighter wearing it that it’s going to go off. This way they can move and reset the activation timer before a false alarm occurs. Of course, these still do occur at times. And some firefighters become desensitized to the sound, and immediate action isn’t taken when it should be, which can have deadly results. So, it’s important both to cut down on those false alarms and take action when it sounds.

A to Z: O is for Overhaul

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Overhaul, in firefighting, is the opening of walls, ceilings, and anywhere else the fire may have extended to that isn’t easily seen. When this fire extension isn’t extinguished, it will cause the fire to reignite and need to be put out again.

Overhaul is a dirty, dangerous, and time-consuming job. It’s done when the adrenaline from battling the blaze has worn off, and is one of the least desirable tasks during a fire. It’s also very necessary. Of course, this has to be balanced against leaving an undisturbed area for the fire to be investigated, among other concerns.

Some of the dangers of overhaul include: structural members, floor joists, ceilings, and walls that may be compromised; chimneys that may have lost support; and compromised stairways all mean a firefighter must remain vigilant. And as the main fire has been extinguished, they may become complacent. A few other problems can be debris(such as puddles of water and broken glass), a toxic atmosphere, and decreased visibility. Added to this is the fact the area is crowded with firefighters, who are likely already fatigued after fighting the fire, using hand and power tools which can lead to more problems.

The senses need to be relied on when performing overhaul, as well as understanding fire behavior. Observing the structure and how it’s built, knowing the way heat travels, and ductwork that could channel fire into other areas of a building all can help find areas where fire may be hidden.

Smoke coming from enclosed spaces is one good indicator of a hidden fire. As well as discoloration on studs, joists, and rafters. These spaces would need to be opened up and investigated for signs of fire. Thermal imaging can also help reveal some of these hidden fires. Listening for crackling or hissing sounds can also lead to more of these. However, with power tools running, hearing these sounds will be more difficult. Excess heat can also be detected by touching the back of your hand to walls, floors, or ceilings.

Some objects in a fire may require even more extensive overhaul, such as overstuffed chairs, sofas, and even mattresses. These should be removed from the structure and dismantled rather than allow a fire to be rekindled in them.

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