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VENTILATING FIRES ABOARD SHIPS

(originally published in Safety at Sea International, May 1994.)

New ship designs including atriums on cruise liners need to take account of ventilation should a fire break out.

John Abell, Senior Lecturer at Southampton Institute's Maritime and Offshore Safety Section explains:

After the development of polyurethane foam by a German scientist in 1937, its use in furniture design and manufacture, especially from the mid 1960s, has meant that traditionally held concepts of fire development in places where this is located have radically changed. Prior to the use of foam in ship's Class A materials, wood, paper etc would still quickly smoke log large areas unless the fire was soon extinguished. The visibility in engine rooms has always reduced dramatically when oil has caught alight.

A series of large fires ashore in the 1950s and 1960s demonstrated that fires could not be successfully brought under control until ventilation had taken place. Tragically 48 people died in the Stardust Disco fire in Dublin in 1981, but the scientists were in no doubt that the outcome would have been far worse if the fire had not self-ventilated at an early stage allowing the irrespirable gases to convect away. Had the ceiling remained intact there would have been insufficient oxygen after 30 seconds of the initial flame up to sustain life.

The traditional Merchant Navy response is to batten down a fire, switch off the ventilation, cool the boundaries with water sprays and remove combustible material which is adjacent to the six sides of the box. In reality the problem may be compounded by casualties in the space, or passengers and crew who have delayed their escape by either not responding to the alarm bells or being unaware of the emergency. A fire broke out on the North Sea ferry TOR SANDINAVIA in 1989, below a loudspeaker. This was soon damaged which then caused two other loudspeakers not to function. Two passengers died from smoke poisoning. Reports of incidents indicate that some passengers and sometimes crew members will not respond to alarm bells ringing, whereas clear concise announcements are essential in order to describe the urgency required. Experimental work has shown that after the initial incubation period the heat release rates grows approximately as the square of the time which is accompanied by the development of large volumes of smoke.

In the early ambiguous stages of the fire growth people do not recognize the danger signs and carry on regardless until a very dangerous situation has occurred. The rapid decrease in visibility often leads to disorientation and, coupled with the ingestion of toxic gases, escape time can be very limited.

A large vessel was retrofitted with a generator prior to temporary lay-up. The sight glass on its diesel tank broke and was replaced by clear plastic hose. When the tank was being topped up it overflowed and the turbo blower on the generator ignited the diesel. The ensuing fire melted the plastic sight glass which caused the tank to empty. Three engineers went in to fight the fire wearing breathing apparatus although everyone had been accounted for and there was no risk to life. However, they made several entries, breaking the golden rule of "change the man not the air cylinder on his back." The shoreside fire brigade arrived and immediately opened a funnel flap to release the smoke and steam. Low pressure warning whistles had already been heard from inside the engine room. The visibility improved very quickly but the engineers were found dead, and totally separated in a space with which they were very familiar. Heat exhaustion had taken its toll. (See Fig. 1.)

Ship's design requires automatic closing of various systems: except perhaps for the sprinklers nothing will open automatically. However, the amended International Convention for the Safety of Life at Sea 1974 which came into force on January 1, 1994 states that "where ships are built after this date, public spaces spanning three or more open decks and which contain varying combustibles, the spaces must be equipped with a smoke extraction system." This is the first time that a purpose built smoke ventilation system has been required in ship design and will basically only apply to new passenger ship construction, although such systems have been commonplace ashore for many years.

One of the most difficult decisions to get right during fire-fighting is when to ventilate. Mariners immediately respond that the extra air induced will feed the fire which will consequently burn more violently. The Master of the SCANDINAVIAN STAR, during the fire-fighting by the shore authorities, intimated that he had been taught to box in a fire and yet the firefighters had been working through his ship opening doors everywhere.

The difficulties of fighting fires inside ships have few worse comparisons so that the benefits of correct ventilation are considerable.

• Crew and passengers can survive longer. Rescue teams can work far more effectively.
• The increased visibility enables the fire-fighters to locate the seat of the fire quickly, less water is used and the reduced steam that is created (water expands 1700 times to steam) is ventilated away.
• Heat and humidity rapidly saps the strength of a fire-fighter and the effective working duration of the breathing apparatus wearers can easily be halved.

The fire load or amount of combustible materials is very high in the accommodation but the fire risk in engine rooms is considerable. More efficient modern machinery is run at higher operating temperatures with a tendency to use heavier, cheaper fuels which have a lower self-ignition temperature. When these land on hot exhausts, large volumes of smoke are rapidly produced. The smoke is allowed to spread unhindered through a large and invariably undivided space. If extraction fans are left on to allow escape or during the initial fire-fighting attempt, the increased visibility and lowering of heat and humidity levels will be considerably advantageous to the fire-fighters.

The general philosophy in fighting fire in machinery spaces is to have one good attempt with portable equipment, after the alarm has been raised, or by a fast response by a breathing apparatus wearing emergency team. If the situation deteriorates then there is no question that there must be an immediate withdrawal, a muster, closing of ventilation flaps and release of the fixed installations. All of this appears to be straightforward but the muster is often difficult to complete especially when personnel evacuate by different exits and do not report to their muster point.

The temptation when a decision seems likely to be in favour of releasing the fixed installations is to switch off extraction from the space. If the muster is incomplete it may well lead to fatalities. The regulations require the ventilation to be stopped by mechanical means; this is often achieved by an electrical switch that is activated when the door to the release mechanism is opened. The alarm will immediately sound and on some vessels other systems will be stopped but once again Is everyone out? There are many examples of over enthusiastic Customs Officers tripping out a miscellany of machinery when rummaging, without prior notice, in the fixed installation release cabinet. This causes much delight to the engineers who must evacuate when the alarm sounds but then have to re-enter to reset the trips!

An old withdrawn "M" Notice (Notice to Mariners) tells us that once the carbon dioxide has been released the engine room must be left battened down for at least 36 hours. However, the thoughts at that time were that the fixed installation was the very last resort and the release was delayed. During fires, mariners have been reticent to release the fixed installations. Experiments carried out by the Americans have shown that carbon dioxide must be released within 15 minutes to completely extinguish a fire and limit the fire damage. The Master may need his engine power back as soon as possible because of the potentially dangerous position the ship is in, so providing that boundaries are sufficiently cool, an entry should be made as low down as possible. In cargo ships and some other vessels access from the propellor shaft is ideal. (See Fig. 2).

Communications are essential from the entry control officer to the ventilating team in the funnel area to open a flap as the fire team enters. Visibility will rapidly improve, the extinguishing medium will be used more effectively and the duration of the breathing apparatus sets will be longer as the heat and humidity decreases. Very hot superheated gases will be vented from the funnel and this area may need to be cooled but water should never be directed into the engine room when people are inside. Tankers do pose greater problems because entry at a lower level is rarely possible. (See Fig. 3)

Providing the conditions permit entry by cooling followed by careful door-opening, the fire fighters must get to a position below or adjacent to the fire if entry is essential and only then can the funnel flap be opened when the attack is ready.

The fire load is high in accommodations even though a considerable amount of material is fire-retardant. Air-conditioning systems on ships will vary considerably but it may be on partial recirculation where a certain percentage, say 70 per cent, is supplied from fresh air and the other 30 per cent continues to circulate. Unless this AC system is switched off immediately the smoke in one area will quickly spread to other areas.

As 153 out of the 158 deaths aboard the SCANDINAVIAN STAR were attributed to smoke inhalation, the investigating committee spent some time looking at the ventilation system. Smoke spread was so rapid that many of the passengers died in less than five minutes. Although the precise time the ventilation was stopped could not be ascertained, it appeared to be beneficial to some escaping passengers. The overpressure in the cabins prevented smoke from seeping in from the corridor; however, this showed that the cabins were tenable for longer until the high volumes of smoke in the corridors eventually smoke logged the cabins. The corridor, which was the escape route, could not now be used without respiratory protection. This was a very unusual fire because it was deliberately set in a corridor where normally there should be very little to burn. The alarm was raised from decks above the fire and so no smoke doors were closed near the fire seat.

Because there is no dedicated smoke extraction system aboard ships, apart from the forthcoming regulations for Atria, all vessels for years to come will have to use the ductings and other openings which are already part of the ship's structure, to ventilate hot gases away. There can unfortunately be no blueprint that can apply to the diversity of designs but ideas can be offered which will help the Master and his Senior Officers to use their existing systems to the best advantage.

The preservation and the safety of life is unquestionably the priority at sea. In accommodations the major risk of smoke spreading from a cabin to the corridor and then to the staircases can have a major effect on escape and evacuation procedures. Crew and passengers, who may not be in the fire zone may also have difficulty in reaching their muster station. The mass of hot smoky gases which are given off in a fire depends almost entirely on the air entrained into the hot phase before it reaches the smoke layer. The amount of smoke increases with height but it becomes cooler and more dilute at the same time. Once it has left the centre of the fire even small differences between the smoke and the surrounding air greatly speeds up smoke movement. When the smoke reaches the ceiling/deckhead it spreads laterally, often at rather high velocities, continuing until a vertical path is available or the smoke cools enough for it to sink and mix with ambient air.

It is therefore essential that when a fire starts in a cabin the door remains closed otherwise the escape routes will become smoke logged. (See Fig. 4).

By using the principle known as "opposed airflow" a minimum velocity of air at the opening flows from the adjacent room into the fire room, e.g. corridor with cabin where there is fire. The extraction system will not be able to remove a significant amount of the smoke produced, however a detector will allow early escape and, providing that cabin doors are self-closing, the fire is contained. The escape routes will remain clear for a sufficient amount of time to allow evacuation. As the cabin supply is stopped the extract will not work so efficiently, however when smoke doors are opened at the ends of the corridor there will be a tendency for fresh air to be drawn into the affected corridor; this should prevent smoke from flowing into the stairs. (See Fig. 5)

To summarize the requirements for this system to work:

• Cabin extraction is maintained
• Supply of air to the cabin is stopped
• Maintain air supplies to stairways
• Doors to be self-closing

A breathing apparatus team will be able to enter with jet spray nozzles into an area with better visibility than would have been if the extraction had been switched off.

Even with the best housekeeping standards, dust will accumulate in trunkings and there is no question that secondary fires may start but, during these early stages, the crew and passengers will have evacuated to a safe area. The bridge team will be able to consult their ventilation plans, establish patrols, and direct fire teams to the areas where fires may lie undetected.

In larger areas such as cinemas, lounges, restaurants and reception areas the same principle may be adopted by leaving the extraction on but stopping the supply. Extraction rates may be larger in these areas but if they are not the space will be tenable for those extra precious minutes, which will allow people to escape, before the smoke flows to other rooms via the doorways and other openings. Once evacuation is complete the fire doors can be closed.

A considerable amount of research work is being undertaken by various ventilation companies to develop dedicated smoke extraction facilities. ABB Fl?kt Marine AB of Sweden has carried out extensive full scale experiments on large passenger ferries. High volume supply and exhaust fans, which far exceed the capacities of the normal systems fitted, can remove a considerable amount of smoke which keeps the escape routes clear.

These developments are directed to passenger vessels where the life risk is very high compared to the cargo carriers. Passenger vessels which are in service now, some over 30 years old, will most likely be with us for many years to come. All ships will have to use the systems already fitted to the best advantage to remove smoke. Early detection is essential so that the fire can be contained and the steps taken in these first few minutes are crucial. The fact remains that if a fire team enters a smoke-logged area their progress will be painfully slow if they are unable to exhaust at least some of the smoke and steam.

Organophosphate Pesticide Exposures

By Rob Schnepp

You arrive on scene to find a 38-year-old female with a complaint of mild abdominal pain.?She states that she has vomited several times, 45 minutes after eating a cheeseburger at a local restaurant. She appears to be very anxious, a little sweaty and obviously uncomfortable; and she graphically describes numerous episodes of watery diarrhea. Her heart rate is 130 beats per minute and her blood pressure is 118/80. She has a runny nose, her pupils are about 2mm in diameter, and she is oriented but slow to respond to your questions. You listen to her lungs and find them to be ?wet? sounding with a respiratory rate of 32.

Any thoughts on what might be wrong? If the title of this piece had been ?Toxic Cheeseburgers: 10 Reasons Why You Should Never Eat Fast Food,? it?s entirely possible that you started thinking about food poisoning. While the signs and symptoms listed above may have lead you down that path, there were other things that should have seemed out of place. Would a patient suffering from food poisoning have pinpoint pupils and wet sounding lungs? Probably not.

I would not expect you to immediately determine an organophosphate exposure, but the point is that a patient of this type may present with mild signs and symptoms. It would then be up to you to make a differential diagnosis and provide the appropriate care. The reality is that this patient may be in serious trouble, and you could be standing at the rare moment when you can intervene at just the right time and truly make a difference.

Since this piece is not about toxic cheeseburgers, let?s get on with the discussion of organophosphates and the concept of proper recognition and the ultimate treatment of an acute exposure. It?s my goal to keep the reading light, informative, and easy to remember. Hopefully, you?ll log off with a better understanding of this group of chemicals, and you can apply it to your own neck of the woods.

At some point in your career, you?ve probably heard about the dreaded class of pesticides called organophosphates. It was most likely from some haz mat guy who said that you could be in real trouble if you were ever exposed to any and that you should take care to protect yourself at all costs. What didn?t get covered, probably, was what to do if you encounter somebody else who?d been exposed. Somebody like the poor guy who works in a bean field somewhere or the farmer who gets exposed to something in his barn that makes him feel all jittery and sick to his stomach. All of a sudden, you find yourself in a position where you wish you?d listened to that haz mat guy a few years ago.

Well, the good news is that you?ve got a second chance! We?ll cover some basics about this group of pesticides and provide you with a few nuggets to file away in case you ever run into this interesting group of chemicals. This is not an article about the chemical makeup of organophosphates per se; it?s more geared at providing medical treatment for the victim of an acute chemical exposure.

With that in mind, let?s look at organophosphates from a broad perspective, specifically their mission in the chemical world. The EPA, for example, looks at pesticides from this perspective: ?A pesticide is any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.? This concept alone should let you know that an unintentional exposure could turn out to be a very bad thing. The suffix -cide, in fact, literally means, ?to kill.? Pesticides, for example, are designed to kill pests, while rodenticides kill rodents, fungicides kill fungus, and so on and so forth ? you get the idea. The thing to keep in mind here is this; pesticides are designed ?to kill? pests, but they can be just as effective on humans. That?s what makes this group of chemicals so important: the profound health effects they will have on you or me, or the guy down the street.

Some common organophosphates you may have heard about, or even run into, are malathion, methyl-parathion, diazinon and a host of commercial compounds like Lorsban and Dursban. It?s interesting to note that the chemical nerve agents Sarin, Soman and Tabun are also classified as organophosphates; that should give you an idea of how nasty they can be.

So why are organophosphates so dangerous? First, as stated earlier, they are fairly common, especially in the farming industry, and very effective at doing their job ? killing things.

Second, most pesticides are toxic by all routes of entry into the body and have systemic effects. This means that an external exposure to the skin or eyes may cause damage to large-scale body systems like the cardiovascular system or the central nervous system. Damage to these critical body systems, specifically due to organophosphates, could include pinpoint pupils, vomiting, tachycardia and/or bradycardia, seizure-like tremors and respiratory arrest. These substances primarily act on the central nervous system, specifically as a cholinesterase inhibitor.

What this means in laymen?s terms is that an exposure may impair the way our nerves conduct an impulse throughout the body. Imagine for a moment that your body is wired like your house. The brain serves as the main service panel, and the nerves branch out through the body like runs of wiring. ?Some go to the kitchen, while others go to the living room and den. When everything works right, the lights go on and off when you flick the switch and all the appliances work like they are supposed to. But what if the wiring arcs, shorts out or becomes compromised? Maybe the lights came on like you expected, maybe they didn?t. Perhaps they stayed on and couldn?t be turned off no matter what you did. Basically, this is what an organophosphate does. It interferes with the uptake of a chemical compound called cholinesterase that turns off some of the chemical ?switches? in your body. In short, a chemical called acetylcholine is secreted by a nerve and travels across a tiny gap to another nerve or an organ that is to be stimulated. Once acetylcholine has completed its mission, the cholinesterase is supposed to break it down and stop the stimulation. This happens a zillion times a day without a problem in a normal, healthy adult; and the whole cycle is completed in a nanosecond. If a person becomes exposed to an organophosphate, however, things change. What happens now is that the acetylcholine does it job, but the specific organophosphate, methyl-parathion, for example, bonds to the cholinesterase and holds it hostage ? the cholinesterase can no longer break down the acetylcholine like it?s supposed to. The stimulated cells then go into a sort of hyperdrive and essentially burn themselves up. The manifestations of that excessive stimulation results in a group of symptoms called SLUDGE, which is an acronym for:

• Salivation
• Lachrymation (teary eyes)
• Urination
• Defecation
• Gastric disturbance
• Emesis

The patient may also appear anxious, have muscle tremors, diarrhea, bradycardia or even tachycardia, hypotension and pinpoint pupils. There may also be huge amounts of saliva in the mouth and upper airway, which could ultimately lead to airway compromise. All in all, he is in BIG trouble and the drugs you administer may not even save him. It stands to reason, then, that an acute exposure requires immediate and aggressive therapy; and even then, you may lose the patient.

How do you determine if your patient has been exposed to an organophosphate? A good scene survey perhaps, but more than likely it will the patient presentation and obtaining a good patient history. The part of the story omitted from the beginning of the article was this: The patient just started a new job with a lawn-care service and had spent the entire day applying some ?bug killer? that her boss told her to use. She ate the cheeseburger in the car on the way home. Would that have been a good piece of the puzzle to know earlier? Absolutely! But remember, it?s up to you to be the historian in most cases. If you?ve been running EMS calls for any length of time, you know full well that you literally need to drag information out of your patients. Usually, if you don?t ask, they don?t tell!

Organophosphate exposures create a unique group of symptoms, and you will need to fit the puzzle together properly in order to see them. Pinpoint pupils are a big clue, so make sure your secondary survey includes a pupil check. The patient may also be wheezing, with no history of asthma or other respiratory disease. Keep in mind that, in cases of mild overexposure, it may be the subtle things that tip you off.

So now you have determined that you have an organophosphate poisoning ? what next? The treatment is largely aimed at breaking the hold on cholinesterase. This is not an easy proposition and has to be done with drug therapy. Here again, thorough and safe decontamination must be completed to assure your own safety. Assuming the scene is safe and you have done a good job of decontamination, here are some guidelines:

BLS Actions

• Protect yourself first!
• Make every attempt to identify the source of the exposure.
• Do a good primary and secondary survey.
• Administer high-flow oxygen. The airway may also require lots of suctioning. Death due to organophosphate exposures is usually from hypoxia or respiratory failure secondary to neuromuscular failure.
• Obtain a full set of vital signs.
• Determine a baseline respiratory effort and rate and closely monitor for changes.
• Obtain a baseline mental status and monitor for changes.
• Put the patient in a position of comfort ? supine may not be the best.
• Rapid Transport ? don?t play doctor on the scene. Once you recognize the situation, get on the road!

ALS Actions (including all the above)

• Use pulse oximetry if within your scope. Any readings below 93% should indicate respiratory compromise.
• ECG: Monitor for tachycardia or bradycardia but remember treat the patient, not the monitor. Don?t immediately jump on cardiac treatment unless it?s hemodynamically significant. Changes in the heart rate may not respond to traditional cardiotonic drugs. In the case of an organophosphate, successful treatment of the underlying problem may correct cardiac disturbances.
• Large bore IV if applicable. You may be pushing huge amounts of IV fluids and drugs so make sure the line is patent. Take care to use aseptic techniques and ensure that the patient has been fully decontaminated prior to poking holes in his skin.
• Track respirations with a bag valve mask or intubate if necessary. Watch out for your own lungs when intubating or ventilating a patient with significant inhalation exposures. There may be swelling in the upper airway so intubate early if it is indicated.
• Administer 2-5 mg?s of atropine IV push or down the ET tube every 2-5 minutes. Your therapy is directed at drying up the secretions. Dilated pupils are an indicator of effectiveness as well as the restoration of an effective heart rate and the diminished effects of the SLUDGE. If administering the atropine via the endotracheal tube, double the IV dose or use high dose atropine diluted in 10 cc?s of saline. This keeps from adding a bunch of fluid to what may already be there. Atropine has no contraindications in this setting. Although it?s not in the scope of practice for most paramedics, the administration of pralidoxime (2-PAM) has been shown to be tremendously effective at treating organophosphate exposures. In regards to the nerve agents (Sarin, Soman, Tabun, etc.), pralidoxime is part of the standard drug therapy to be administered. It can be administered as an infusion at 1 gram over 30 minutes or as a 1 gram bolus. Other studies have shown that an IV infusion of pralidoxime at a rate of 500mg per hour may be effective. This is largely a treatment given in the hospital, but one you should be aware of. The therapeutic goal of either of these drugs is to dry the respiratory secretions and improve the oxygenation of the patient. It?s not unreasonable for a patient to receive more than 500mg?s of atropine in a 24-hour period. This may seem extreme, as we are accustomed to administering atropine in 0.5 and 1 mg doses, but should illustrate the benefit of sustained and aggressive treatment.
• The patient may also be seizing. If this occurs, treat for seizures per your local protocols.
• In the event of cardiac arrest, treat it like any other non-chemically induced code.

Other important components to treatment include things not traditionally associated with pre-hospital medicine. In the case of an acute exposure where you suspect organophosphates, make every attempt to identify the offending substance. It?s not as critical if you can?t make a positive ID in the first few minutes, but, down the road, should the patient become stable, it would be helpful to know. It?s also important to understand the need for thorough decontamination and personal protective equipment. The intent of this article is not to discuss the pros and cons of technical decon, but any responder should put this action at the top of the priority list when dealing with chemical exposures. It?s so important, in fact, that no treatment should begin until you are reasonably sure that you won?t become a patient yourself.

Additionally, many organophosphate pesticides are mixed in a hydrocarbon media prior to application. This means that if the pesticide is in a liquid form, some sort of flammable liquid could very well be present. It?s not the flammability that should concern you so much, although you should consider the danger, but it?s the effect that most solvents have on latex rubber. Many of us in the EMS field use the standard latex rubber gloves for medical calls, but the problem with latex rubber and many hydrocarbons is this: they break down the latex like gasoline in a Styrofoam cup. That?s an extreme example, but your thinking should revolve around making sure you don?t wear any old gloves and assume you?ll be protected. Each particular substance may have unique incompatibilities with your gloves, so make sure that they will work before putting your hands on an exposed patient. It?s bad form to show up as a rescuer and end up in the hospital!

Under the best circumstances, chemical exposures are difficult to deal with. We become accustomed to dealing with heart attacks and trauma, but may feel a whole lot less comfortable with the kind of patient described at the beginning of this piece. The keys to being successful in this setting are to remember these 5 basic points:

• Provide for your own safety first!
• Try to ID the source of the exposure
• Decontaminate the patient if it?s your responsibility
• Provide the appropriate BLS or ALS measures
• Package the patient and transport

The final comment is directed at the single most important governing principle when dealing with chemical exposures:

Everything you do should be geared at moving the patient toward the hospital.

This is where the definitive care takes place. Don?t delay in getting the patient to the most appropriate facility in the shortest amount of time!

?

Forcible Entry Size-up & Tools

By Mike Lombardo

Size-up of the door and occupancy will help us select tools and give us an idea of what we will encounter inside the door. The direction a door swings and hinge locations are some of our size-up factors. The vast majority of residential buildings will have inward-swinging doors. This will also mean the hinges are on the inside of the door. An outward-swinging door in an occupancy of this type usually indicates a closet or basement entrance. An inward-opening door will generally signal a bedroom or bathroom. The threshold in a bathroom doorway is also a good size-up factor and can be a great guide during a search. In multiple dwellings, an outward-swinging door can be a danger sign. Utility closets will have outward-swinging doors that may contain haz-mats with which to contend. In public-housing-project buildings, we may find an elevator door that swings out. If this door has an inoperable interlock device, it may open to a shaft without an elevator at that floor. When dealing with outward-opening doors it must be remembered that the hinges will not always be visible, they may be recessed into the door.

The construction of the door, the frame, and wall, are also important to us. The type of door construction ? steel, wood, solid core, or hallow core ? will determine how we will place our prying tool. Some of our best indicators when looking at a door are the lock faces and keyways.? If we find a door with a faceplate and no keyway, for instance, we may want to consider an alternative entry point. It probably is not the primary door the occupants use and may be a very difficult door to force. When looking at a door, determine if there are bolt heads coming through that could indicate a drop bar is behind it. These bars may be simple 2 x 4?s dropped into an angle iron frame or elaborate mechanical bars that recess into a wall at the doorframe. Are there any keyways that are not at the edge of the door? If you find a keyway in the center or off-center you may be dealing with a lock that has a buttress to the floor. This could also indicate a lock with rods encased into the door that slide into the frame and wall in two or four directions. The doorframe construction will often determine what tools we use. For instance, a weak stop will prevent using hydraulic tools, such as the Rabbit Tool, a lightweight, hand-carried spreading device, because the stop will fail before the lock does. Or with a very strong door and frame set in a drywall partition wall, it will be easier to breach the wall rather than forcing the door.

The type of occupancy is also important. Doors at ?Sandy?s Muffins and Buns? will probably not be as tough a problem as a door on ?Christa?s Rare Jewels and Gold.? Occupancy can also be a factor when determining how much of a forcible entry problem we face. A fire in a large multiple dwelling, or worse, in a single room occupancy^[1], can cause a lot of stress for an IC when he has one truck at a fire on a lower floor of one of these. One idea is to send a team with a hydraulic tool (rabbit) to the floor above and force every door possible. This will allow other teams to move in and search without being spent from forcing each door.

There are three basic types of forcible entry operations: conventional, through-the-lock, and special operations (cutting, breaching, etc). Conventional forcible entry involves two methods: mechanical, which involves the use of hydraulic tools, and manual. Through-the-lock forcible entry involves removing part of a lock, then using a ?key? tool to duplicate the action of the key.?Special operations will involve using cutting tools and other equipment to force gates, roll-up doors and other types of high-security devices that would not be easily forced using conventional methods. Some boarded-up applications on vacant buildings may require special tools or operations.

The first operation we will talk about is manual forcible entry. The tools of choice are a Halligan tool and a striking tool, such as a flat-head axe, sledge, or splitting maul. The type of Halligan tool is important. Pinned or cast tools can fail. Forged tools are better. A tool with a bevel in the fork and slight bevel in the adz is preferred because it imparts more leverage than a straight fork or adz.? The fork must be narrow enough to allow it to be forced between the door and jam. Many Halligans on the market today are manufactured with a fork that is entirely too large, preventing it from getting into the jam. A pike axe is not a very good choice for forcible entry because it makes a poor striking tool. The consequence is that we end up chopping at a door, creating what I like to call ?fireman frustration marks.? A flat-head ax or maul is a much better choice. Heavier, rather than lighter, will help too. Eight-pound axes and ten- or twelve-pound mauls do a great job.

We have talked about a hydraulic tool (Rabbit) already. Other useful items are a rotary saw with a metal-cutting blade, a torch, battering ram (the kind the SWAT teams have are super), a K-tool, and some personal tools. I have carried, for quite some time, a pair of water-pump pliers. I have ground the ends down, and one end is heated and bent to create a short L. This gives me the two key tools that are found in the K-tool kit. Many lock cylinders, such as a pivoting deadbolt, can be pulled off with these pliers, allowing manipulation of the lock with the ?keys.? We must keep a good reversible screwdriver in our personal tool inventory. A shove knife is very handy also. With floor locks, such as ?The Club for a Home,? a shove knife will let us know if there is a lock at the floor level by sliding the knife in and hitting the lock or barrier.

This is a look at size-up and tools for some common forcible-entry problems you may encounter. There are many other tools on the market today, their application limited only by your imagination. Burglars keep the lock industry on their toes, but, unfortunately, we often find ourselves one or two steps behind the lock industry. It is imperative we continue to pursue new techniques while at the same remembering the basics.

	Left: Size-up should consider door, frame, and wall construction as well as locks present and door swing direction. This photo is an obvious reason why we should determine conditions behind a door before we try it. Below left: Bolt heads can signal a very difficult door! Below right: The inside of the door shows bars that slide more than two inches into the frame and wall.
Right: Not all Halligans are the same. Notice the difference in forks of the three tools. The tool at the top is the far superior tool.
Above: When we don?t have the correct tools we can end up with ?fireman frustration marks? on the door.	Above: Handy tools for forcible entry situations. From left to right, screwdriver, water-pump pliers (Channel Lock) with ends ground and bent to create ?key? tools, Vise Grips for securing padlocks during cutting operations and pulling slats on roll-up doors, and webbing to control doors while they are being forced. These are just a few of the many uses.

Garage Fire Considerations

Many articles have been written over the years about various methods to initially attack an attached-garage fire in dwellings. Because there are so many variations in building construction, I have found the need to tailor my initial attack depending on the results of the rapid size-up.

We must always remember to follow "RECEO"¹ in our decision-making process. I believe that one action common to all firefighters — once the initial size-up has been conducted and any rescue ruled out — is the tactic of checking the interior and advancing a line inside. Once inside, we must check the integrity of the interior door and check for fire above or below. If fire is present in the attic, we can usually confine the beast from underneath without opening the interior door; this action can minimize damage. Once the interior position has been taken, exterior lines may be used. This type of offensive requires ongoing communication between interior and outside companies.

When we determine the fire has not spread to the interior, fire attack from the exterior has proven to be a very effective first option. Many dwellings have a side access door. This location is my first choice, as access is easier and streams are not apt to breach the firewall. However, in some cases the side-access door may not exist. In this situation, the attack can be initiated from the large garage-door opening. With the interior company still in place and attic exposed, any extension which might develop can be immediately confined.

A few considerations during this type of offensive are as follows:

• Access from the large garage door may be difficult to lift as springs or cables could have failed. Use care to avoid back injuries.
• If the large door is easily opened or already open, you must take safety precautions, which will include the need to prop the door in the open position. An 8-foot pike pole works well. Also, place a firefighter in charge of the door to avoid accidental closure. I recall an incident in San Francisco a couple of years back when a garage door accidentally closed. This happened to be the firefighters' only means of egress. The fire claimed the life of a 25-year veteran lieutenant and critically injured two others, one of whom was permanently disabled. Remember, no fire is routine, and we must always plan ahead to protect ourselves.

Note the garage side access door. If a significant number of locks are present, forcing entry may be time consuming. Consider punching a hole in the door to apply a stream. With a fully involved garage, going indirect may be the only option.

• Electric door openers and exterior locks will require forcible entry. If this challenge is presented, you can consider punching a hole in the door or use a garage window if one exists, and apply an exterior line using the indirect method. As we all may recall, Lloyd Layman explained years ago that applying water in a confined space would create a steam conversion ultimately squelching the fire. Note: If you have the luxury of arriving with an additional company which carries power tools use those resources to cut holes for access.
• Metal or wood roll-up doors with throw bolts may be too labor intensive for the initial company without forcible entry capabilities. If you are confronted with this complication and there is no side access door or window, your attack should be made from the interior immediately.

The window on the left leads directly into the garage. If no side access door is present, consider using garage windows to attack indirectly.

You might be asking yourself: "Since some of these actions seem like too much work, why not attack these fires the easy way, right from the interior door? Well, this tactic is one that is used around the country. However, my reasons for considering the alternate methods are as follows:

One of our responsibilities is to reduce property loss! If no interior extension is present, and we open the interior door to attempt extinguishment, all of the products of combustion flow directly into the interior causing unnecessary damage and reduction in visibility. I have seen this many times. The natural tendency is to put the line into operation from inside because "we were first in and this is our fire." Then we say to ourselves, "We are attacking this from the unburned, just like the book says." This initial line placement may not end up being the most glamorous assignment, but it will play an important role in the operation and preserve property. The owners will be grateful for our efforts to preserve their property, and with customer service being so important these days, we can only benefit from the good press.

Garage fires pose some interesting challenges, especially with regard to extension. Some examples are:

• Missing Firewall: Many occupants recognize the abundance of storage space which exists in the attic behind the garage firewall. Since access can be a problem for them, the firewall is removed. If this condition is present, our job is more difficult, as the fire can quickly communicate directly into the living quarters. This potential re-enforces the need to, on arrival, advance a line into the interior and pull the ceiling to check for extension.
• HVAC System: These systems are located inside the attached garage of many dwellings and pose a significant problem. The ductwork serves as a direct line for fire travel throughout the fire building. In single-story buildings, duct work runs under the dwelling and/or through the attic space. In two-or-more-story dwellings, it is common to find ductwork running through the concealed joist space of the floors. In any event, we must check for extension in these hidden spaces.

Note the interior firewall of this garage is intact. This may not always be the case. If the firewall is missing or has holes, fire will spread to the interior of the house. A line should be led to the interior of the house and positioned on the opposite side of the door where walls and ceilings should be opened and checked for fire extension. The door should remain closed to prevent steam,
smoke, and other products of combustion from entering the house. Note the ductwork from the heating, ventilating and air conditioning system. A failure of the ductwork will provide an avenue for fire and products of combustion to spread throughout the house. Before you leave the scene, check the integrity of the ductwork and ascertain that fire has not entered it.

I remember a fire a few years back in a wood-frame, two-story, single-family dwelling, built in the late '70s. The fire originated in the garage. Following extinguishment, and during the investigation, we noticed a wisp of smoke, with the exact location unknown. Further investigation revealed the fire had traveled through the HVAC ductwork and started various separate fires throughout the second floor. Besides being a total surprise, this turned out to be an extremely labor-intensive fire with an incredible amount of overhaul, the type you would expect from a fire in a building with balloon construction. This house looked like a war zone following our overhaul procedures.

Constantly evaluate the building throughout overhaul operations. Should you have the luxury of thermal imaging capabilities, consider using this tool. All of your efforts will pay off and reduce chances of a rekindle. Remember that a rekindle will neutralize any support from the property owner you may have gained earlier in the incident.

Consider that high-tech apparatus, pumps, hoses, water additives, nozzles, and personnel would be ineffective in ?putting the wet stuff on the red stuff? if hoses were unable to be attached to pumps and nozzles, and that fire-attack personnel could not effectively follow a hoseline out of a building (in an emergency) if sections of hose were not able to be connected together.

With these thoughts in mind, let?s consider how we can increase the effectiveness of most hose couplings when applied to fireground operations.

BOWL

Currently, most hose couplings are manufactured in male or female configurations. The portion of a coupling attached to a hose is referred to as a ?bowl.?

Interestingly, bowls are commonly produced with a straight cut at the rear of a bowl (where the hose enters a coupling). This results in a sharp edge that can restrict the movement of the hose when being pulled around corners in structures, and across concrete, asphalt, and other similar surfaces. This is graphically demonstrated by observing the abrasion marks on most couplings.

To minimize this condition, hose couplings can be ordered with ?tapered bowls? which eliminate the sharp edge at the end of the bowl, resulting in hoses that are much easier to pull around corners and across ground surfaces. (Notice the lack of abrasion marks on the tapered bowl ends).

Additionally, a tapered bowl does not have a tendency to ?hang-up? on a corner when being advanced in the interior of a structure. Remember that some hose manufacturers do not make hoses with a tapered bowl unless it is specifically requested (normally at a minimal cost).

DIRECTION OF TRAVEL

Occasionally, it is necessary for fireground personnel to follow hoselines for the following considerations:

• An attack team suddenly needs to follow their attack line out of a structure due to deteriorating conditions.
• It is suddenly determined an attack team needs to be rescued due to a flashover, building collapse, etc. Normally the most direct path to their probable location is for a search team to initially follow and search along the path of the attack line to the nozzle.

Although the concept of personnel following a hoseline to reach a specific location may seem simplistic, implementation can be difficult due to the following factors:

• Often, the development of an interior hoseline will not result in a straight hoseline between a nozzle and entrance (or exit) opening, since hoselines are usually looped and/or crossed by other hoselines.
• The need to determine which way to follow a hoseline may arise suddenly. (Remember, one direction will lead to the nozzle, and the other direction will lead to the exterior of the structure).

Therefore, it is imperative that personnel practice and become familiar with the concept of following a hoseline with only their hands as a reference point.

Personnel can easily determine the proper direction of travel along a hoseline if they are able to feel a coupling with their gloved hands. Here's how:

Assume a nozzle is connected to a male coupling. Following the hose behind male couplings will lead towards the pump (outside the structure), and following the hose behind female couplings will lead towards the nozzle (into the structure).

With practice, it is easy to distinguish between a male and female coupling by feel only. The lug on a female coupling is one-third to one-half the length of a lug on a male coupling. With this knowledge, any firefighter can grasp a coupling on a hoseline and quickly determine which direction will lead to a desired location as follows (assuming a forward lay):

• To reach the exterior of a building, follow the hose behind the male coupling.
• To reach the nozzle, follow the hose behind the female coupling.

Additionally, before entering a structure for a search-and-rescue operation that will depend on a search team following a hoseline, determine (from the appropriate pump operator) the appropriate hoseline to follow into the structure, how many feet of line are into the structure, and what is the type of hose lay (forward or reverse). Remember that a 2?-inch line can be forward or reverse and 1?-, 1?-, and 1-inch lines are forward only. Every firefighter should be familiar with this concept.

OPERATIONS

Of all the hose sizes that are available to fireground personnel, what size of hose is most commonly used to extinguish fire? Answer: 1?-inch. The reason is simple: 1?-inch hoses can be implemented by one firefighter; they are capable of 200 gpm; AND they are capable of extinguishing most fires.

However, some fires require more than 200 gpm in concert with the ability to deliver that water to the seat of a large fire. Question: Why do a high percentage of fireground pictures in fire service magazines depict 1?-inch lines being used on large fires that require ?firepower?? Answer: When 1?-inch lines are commonly used for the ?day-to-day? fires, they will also be used on larger fires.

Furthermore, have you also wondered why spray nozzles are commonly used for defensive operations when these types of fires often require depth and penetration of hose streams? Answer: As the spray nozzle is the most flexible nozzle, it is normally pre-connected to master stream appliances and attack lines. Therefore, unless a company officer specifically requests the use of a specific hose or appliance with the appropriate nozzle that will effectively deliver the appropriate amount of water to the necessary location, fireground personnel will not be as effective as their equipment is capable of making them.

Flashover

By Vincent Dunn

?

Flashover!?It is the most dangerous time of a fire.?When the room bursts into flame, flashover has occurred. The scientific definition of flashover states it is caused by the radiation feedback of heat. Heat from the growing fire is absorbed into the upper walls and contents of the room, heating up the combustible gases and furnishings to their auto-ignition temperature.?This build up of heat in the room triggers flashover.

Flashover Time-Temperature Curve

Temperature of Fire
?	Time of Fire

Flashover signals several major changes in a fire:

1. It is the end of an effective search and rescue in a room; it means the death of any person trapped in the blazing room ? either civilians or firefighters.
2. It signals the end of using a portable extinguisher to extinguish the fire; an attack hoseline is required after flashover occurs.
3. It signals the end of the growth stage and that the fire is in the second stage of combustion ? the fully developed stage.
4. Finally, flashover signals the change from contents to a structure fire. This is the beginning of the collapse danger. Structural collapse potential starts in the fully developed stage and becomes the greatest in the decay stage of a fire ? after the fire has been extinguished.

Flashover does not occur at every fire. Sometimes flashover does not take place. At some fires flashover does not occur for a long period of time. However, flashover may occur suddenly, without warning and just when firefighters arrive on the scene. Firefighting is dangerous enough; we do not want a surprise at a fire operation.

When operating at a fire, chiefs and firefighters may want to delay flashover inside a burning room. By delaying flashover, you can "buy" several minutes which may be critical. For example, you may want to delay flashover to make a search and rescue of the burning room or allow a firefighter to go above a fire to make a rescue of a trapped victim. Or, you may want to delay flashover to gain several minutes when there is a delay in the placement and operation of the first attack hoseline.

Three Ways to Prevent Flashover

1. Venting: By venting doors and windows of a burning room you release the build up of heat in the room. This is most effective during the early part of the growth stage when a room is filled with smoke and not too much heat. This slows down flashover by releasing heat from the room delaying the radiation feedback effect. This venting also improves visibility for a search in a smoke-filled room.
2. Not venting: At some fires, the exact opposite may delay flashover. By not venting and, instead, closing the doors or windows to the burning room, you may delay flashover. This is most effective when the room is full of smoke and large amounts of heat, and the fire is at the end of the growth stage, shown in the above time temperature curve, just before flashover is about to occur. The logic behind the tactic of not venting is flashover is delayed in a superheated room by starving the fire of oxygen, which slows down the combustion rate, which, in turn, slows down the build-up of heat in the room. This slows down the radiation feedback effect. The combustion rate a fire depends on many factors, but the greatest effect on a fire is the amount of oxygen being supplied to the blaze. An example of when you might close a door and not vent a fire to delay flashover would be when there is a delay in stretching a hoseline, all persons are out of the burning room, and it is too hot to enter for a search and rescue.
3. Portable extinguisher: The discharge of a portable extinguisher can cool the heat down in a burning room temporarily and delay flashover.

To avoid getting trapped by flashover, firefighters must know the warning signs of flashover.

Warning Signs of Flashover

There are two warning signs which may signal the danger of flashover: heat mixed with smoke and "rollover."

1. Heat: When heat mixes with smoke, it forces a firefighter to crouch down on hands and knees to enter a room to perform search and rescue. This must be considered a warning sign that flashover may occur. Heat buildup in a smoke-filled, burning room is a triggering event for flashover. If the heat in the smoke-filled room causes us to crouch down near the floor, we must consider the danger of flashover. If there is little or no heat mixed with smoke then the danger of flashover is less severe.
2. Rollover: Rollover is fire-department jargon for the appearance of sporadic flashes of flame mixed with smoke at ceiling level. It is usually seen outside a burning room when the first attack-hose team waits for water to be supplied to the hoseline. When the door to the burning room is partially opened and smoke is flowing out into the hallway, the smoke may ignite into sporadic flame. Rollover is caused by heated combustible gases in smoke, which ignites into flashes of flame when mixed with oxygen in the air. Rollover precedes flashover. Rollover is another warning sign of flashover, which may be seen in the smoke coming out of the tops of doorways or window openings of burning rooms before flashover occurs.

Whenever one of these warning signs is seen and a flashover danger exists, defensive search procedures must be used by firefighters. Standard tactics and procedures must be curtailed and defensive search-and-rescue procedures substituted when there is a danger of flashover.

Defensive Search Procedures

There are two defensive search procedures that can reduce the risk of death and injury from flashover:

1. At a doorway: A firefighter should check behind the door for the victim, then enter the hallway or room not more than five feet, sweep the floor, look for unconscious persons, call out and listen for a response. If no response is forthcoming, close the door and wait for the hoseline. As the attack hoseline advances, conduct a search and rescue behind the line, searching room and space outward from the hoseline.
2. At a window: When a window breaks from either the heat of the fire or because it is opened by the firefighters and superheated smoke and rollover are seen in the smoke, preventing a firefighter from entering, the firefighter should crouch down below the heat and sweep the area below the windowsill with a tool. In some instances a person may collapse at the window and fall right below the sill. If a victim is found, a firefighter might be able to crouch below the heated smoke and flashes of flames coming out the window and pull the victim out of the window to safety.

After a flashover occurs, the point of no return is reached, a point beyond which a trapped firefighter will not survive and will not reach the door or window he or she entered. How far inside a burning room can a firefighter be and still escape back out the door alive ? and not suffer serious bums after a flashover occurs? The million-dollar question is: how far into a superheated burning room that appears about to flashover should a firefighter enter?

Beyond five feet is the point of no return. We can figure this distance out by putting together several facts. For example, tests conducted in 1960 in California discovered that fire temperatures of 280?-320? F cause intense pain and damage to exposed skin. Also the average temperature in a room that flashes over is 1000?-1500? F. And, time and motion tests in the Handbook of Fire Protection reveal that the average person moves 2? feet per second when walking. Now, the question is: how long can a firefighter?s protective clothing take 1000?-1500? temperatures before the firefighter receives serious burns. If there is 1000? flame in a burning room that has just flashed-over and a firefighter is five feet inside the room, and crawls back to the doorway at 2? feet per second, he will feel 1000?-1500? heat on exposed portions of skin or through the fire gear for two seconds. The firefighter may not receive any burns. If you say you can enter 10 feet into a room about to flashover and it does, and you try to escape you will experience 1000?-1500? for four seconds. Fifteen feet inside a room that flashes-over, and you must crawl back to the door for six seconds. Think about it.

Lessons Learned

Firefighters should know the definition of flashover ? a room bursting into flames. They should know the warning signs of flashover. Also, firefighters must know how to delay it. And most importantly for firefighters' safety and survival, they must know defensive firefighting procedures ? how to search and stay alive.

Your options are limited. You are the only truck company on the first-alarm response--the second-due truck is a mutual-aid response. For the critical initial stages of the operation, it's only you, your driver and one firefighter. You direct the firefighter to force entry into several units ahead of the extending attic fire as you and your driver ladder the roof and prepare to ventilate the building.

In this scenario, the truck officer has correctly identified a potential problem. The fire in the end unit has extended into the common attic space and will extend horizontally to the other end of the building unless it is stopped. When the officer and driver reach the roof, strategic objectives will be as important as tactical operations if the truck officer is to be effective within minimal time and staffing constraints.

The strategy for roof ventilation operations will be offensive or defensive. The primary focus of offensive roof ventilation is to create a ventilation opening over or as close to a fire as possible, as safety permits. This type of ventilation is designed to do the following:

• vertically channel a fire and its by-products
• limit horizontal extension in a structure
• remove heat and smoke from a structure
• minimize the potential for flashover and backdraft
• increase the safety of fireground operations

If offensive roof ventilation operations have been completed, if they cannot be performed for safety reasons, or if fire already has self-vented through the roof, defensive roof ventilation operations should be completed if necessary. The purpose of defensive roof ventilation is to create an opening ahead of a horizontally extending fire to change the horizontal direction and extension of fire, heat, and smoke to a vertical direction, thereby reducing or eliminating the horizontal fire spread.

Defensive roof ventilation is usually accomplished by the strip (or trench) vent. The strip vent is a long, narrow opening in the roof decking, generally from exterior wall to exterior wall (or fire wall to fire wall) and approximately three feet wide, ahead of the horizontally extending fire. This opening allows you to strategically channel and redirect the fire, slowing horizontal extension and facilitating knockdown. With a strip vent you are, in effect, "drawing your line in the sand" against the fire. Usually, committing to a strip vent means that you have a well-advanced structural fire that is moving horizontally over a large area at such a rate that you cannot stop it with offensive venting tactics, given on-hand resources. (Editor's note: The term "defensive" ventilation is convenient because it rightly differentiates between the strip vent and other methods of roof ventilation. However, there is not connection between defensive fireground strategy. The strip vent is only "defensive" from the aspect of "letting the attic fire come to you." Venting of any kind is inherently an aggressive operation. Likewise, effective strip venting requires aggressive, offensive tactics by engine and truck crews operating from interior positions--for example, pulling ceilings and knocking down fire in adjacent occupancies/exposures, etc.)

The strip vent has been used successfully as the primary vent opening in a variety of fire situations in a variety of structure and roof types, but all these successful operations shared common factors--the fire was such that offensive venting either could not be accomplished or had limited effectiveness, fire was in control of a large area of common attic or cockloft space, an aggressive interior attack still could be made from unburned or partially involved portions of the structure, there was a significant attic area over which the fire had to spread, the strip vent could be made in an effective and timely fashion, and a strategic decision by the commanding officer was made to "sacrifice" the heavily involved portion of the structure to save the rest.

Many factors influence the strategic decision to vent defensively. These include building and roof construction, fire conditions, fire load, manpower, building dimensions, firefighter experience and training, and so on. Time is critical. The officer must ask himself, 'Given my resources, the extent of the fire, roof construction, personnel safety, and so forth, can my personnel make a 30' or 50' or 70' long, 3' wide opening in the roof in the time it will take the fire to reach that point? What is my return on investment for this tactic? Will a sizable vertical vent (offensive) opening as close as possible to the fire area delay fire spread significantly and, most important, improve conditions such that personnel can operate effectively and safely in interior positions?' The officer in command must weigh many factors. Communication with fireground companies is essential to acquire the needed information on which sound decision making is based.

General roof venting tactics

Prior to a roof-cutting operation perform/address these tactical and procedural considerations:

Ladder and approach from the uninvolved area. A minimum of two ladders should be raised away from or opposite the location of a fire. This allows personnel to start and return to the strongest portion of the building and their means of egress.

Ladder the strong areas of the building roof. Normally, the strongest portions of the building are at the corners. Avoid placing ladders over horizontal openings (that is, windows, doors, etc.). Other areas that offer strength are hips, valleys, and ridges.

Raise the fly of an extension ladder/aerial above a parapet or roof for visibility. If a ladder is a primary means of egress from a roof, make it easy to locate. Therefore, do not limit the extension of a ladder above a roof/parapet to three or four feet.

Deploy properly equipped and adequate personnel. Roof ventilation operations are simplified and safety and accountability increased when a minimum of two firefighters are used. Consider the following equipment the basic minimum necessary to accomplish roof ventilation operations:

• complete turnout gear and SCBA
• portable radio
• pickhead axe (used for prying and as a backup for power saws)
• pike pole, trash hook, or other suitable tools for removing cut sections of roof decking
• power saws--Historically the rotary saw has been widely used as a viable roof ventilation tool although size, weight and the "gyroscopic" effect of the blade often detract from its effectiveness. In applications other than metal-deck roofs, the modern chain saw has proven to be a superior roof ventilation tool because of its effectiveness and ease of use--which often translates into firefighter safety.

• minimum four-cubic-inch engine size, adequate for multiple layers of roofing material
• 16" to 20" sprocket tip guide bar (cooler running chain and reach)
• large air cleaner (increased time in smoky conditions)
• muffler guard (usually a piece of aluminum on the front of the muffler, which minimizes maintenance and cleanup operations)
• carbide-tipped chain (superior to standard chains). A new carbide chain can successfully cut through 14-gauge steel without ruining the chain).

• What is the fire's location and is fire showing through the roof?
• Is the roof stable? Is a portion of the roof sagging? Are there heat blisters?
• Does the roof have ventilators, vent pipes, or skylights, and are they issuing smoke?
• What are interior/attic conditions? Communicate with interior fire attack crews and the incident commander.

• corrugated metal indicates a metal-deck built-up roof with open web bar joists
• 1" x 6" sheathing indicates a conventionally constructed roof
• plywood on a newer building is an excellent indicator of lightweight construction.

• visual size-up (what areas of the roof are issuing fire or smoke?)
• small inspection/indicator openings (kerf cut, etc.) which can be cut with an axe or power saw in the roof decking and used to determine the location and extension of fire.

Sound the path of travel. Sounding with an axe, pike pole, trash hook, or other suitable tool in front of your intended path of travel will help verify the roof's safety. Remember, don't sound with your feet--they are connected to your body.

Work toward the ladder/means of egress. Ventilation cuts should be designed to start in the weakest portion of a roof (toward the fire) and finish in the strongest portion of roof (away from the fire).

Keep the wind at your back. When possible, ventilation cuts should be planned to keep the wind at the back of personnel.

Cut only as deep as necessary. Unless otherwise necessary, ventilation cuts should be cut through roof decking only. Cuts deeper than roof decking increase the possibility of cutting through structural members.

Predetermine your path(s) of egress. Always know how to safely exit a roof. Generally, exit a roof from the same area you used to walk onto it. Never get cut off by fire from your means of egress.

Consider the principle of distance for time. Strip ventilation can be a time- and personnel-consuming operation. Therefore, if strip ventilation is necessary, place enough distance between the extending fire and the strip operation to allow the strip to be completed before the fire can travel pass the strip opening.

Consider timing in strip ventilation operations. Since strip ventilation operations can be a time- and resource-intensive operation and an opening can accelerate the travel of fire toward its location, conduct strip operations as two distinct operations. The first operation is to cut the strip; the second is to open the strip.

Coordinate interior attack operations with strip ventilation operations. To be successful, strip operations also require the ceiling under (or as close as possible to) the strip opening be removed to allow access for a hose line into the attic to extinguish the attic fire. This operation requires coordination and communication between roof and interior personnel.

Make sure the strip cut is made from wall to wall. If not, fire could pass around the ends, destroying the vent's effectiveness.

The roof must be walkable. The strip vent operation is a power-saw operation. While the strip cut originated in flat-roof applications, experience has shown that it can be used successfully on pitched roofs, provided the pitch does not compromise firefighter safety.

Wood roofs--against the construction. Strip ventilation openings that are cut against the construction will require additional cuts and time to complete compared with strip ventilation openings cut with the construction. To cut against the construction:

• Make two parallel cuts about three feet apart across the rafters and section of roof to be ventilated. Depending on staffing and equipment, these cuts may be made singularly or simultaneously.
• Make cuts between the rafters every 16 or 24 inches, depending on the spacing of roof members. This produces small sections nailed to single rafters. These panels are easily hinged in the form of louvers or removed.
• Remove or hinge the panels. Pry up with a suitable hand tool to remove or hinge the cut sections.

• Make two parallel cuts on either side of a rafter. These cuts should be near the outside rafters.
• Make crosscuts between the parallel cuts about every four to six feet. This enhances removing plywood and/or multiple layers of roofing materials.
• Remove the cut panels of decking. Each 4' to 6' panel is nailed to the centre rafter and is easily removed or louvered.

• Make the first cut along the length of the rafter, as close as possible to the rafter without cutting it.
• Mirror this cut along the second rafter, again as close to it as possible.

Metal-deck roofs. Although the methods necessary to strip ventilate metal-deck roofs are similar to those of wood roofs, initiating a strip ventilation operation in a metal-deck roof is enhanced by a two-step process that consists of removing the insulation or composition covering and then removing the metal decking from the bar joists. This is due to the fact that metal cutting blades are not effective in cutting through the insulation/composition covering. For example, a strip opening cut against the construction can be accomplished as follows:

• Using a chain saw or rotary saw with a wood-cutting blade, make two parallel cuts about three feet apart. It is only necessary to cut through the layers of composition and insulation. Let the teeth ride on top of the metal corrugations.
• Make crosscuts every four feet between the parallel cuts. This ensures that the cut sections of composition/insulation are easily removed.
• If the metal decking under the cut sections is cold, strike the sections to be removed with an axe or similar tool. This will loosen the tar or adhesive bond between the metal corrugations and the layers of composition/insulation, facilitating removal. If the metal decking is warm, the cut sections should be easily removed.
• Remove the cut sections and place on the roof away from the fire.
• Two parallel cuts are now made through the metal decking with a rotary saw and metal-cutting blade similar to cuts made in the insulation/composition layers.
• Crosscuts are then made between the metal bar joists. This process ensures that each of the metal sections is attached to a single bar-joist only and is easily louvered and removed with minimal effort.
• Although this task is easily accomplished, it is a time- and blade-consuming operation.

OPPOSING HANDLINES

By Vincent Dunn

MIKE SMITH
Washington, D.C. Fire/EMS Deputy Chief

We live in stress-filled times. For those who are parents it seems to be a constant for us to be transporting someone somewhere. For those working two jobs or going to school while also being members of the fire service it seems that we are able to accomplish many things at once giving us that can do attitude. Does this impact our performance on the fire ground?

On the fire ground how do fire fighters run out of air? Why do truss collapses occur trapping or killing firefighters? Why do fire fighters get caught in flashover conditions? Why do fire fighters get lost and then succumb to the fire conditions? Why do Incident Commanders get caught short on requesting resources while their people are battling conditions on the interior? How long will it take for a Rapid Intervention Team, RIT, to rescue and extricate one or more fire fighters?

A colleague in Providence, Rhode Island, Lt. Greg Crawford, runs one of the very best SCBA classes in the country, in my opinion. His approach is confrontational to the participants but after taking the class no one will leave without understanding and appreciating the connection between the life of the wearer and the equipment. No one will ever again go into a hostile IDLH atmosphere without knowing how long his or her SCBA will last under duress.

The truss collapse in Hackensack, New Jersey, occurred in 1978. Many thousands of hours of presentations have been given to members of the fire service on the dangers and limitations of truss construction. The building industry has actually taken truss construction to new heights of danger with the advent of TGI beams and increasing use of micro-lams. We continue to attempt to outlast the collapse time frame with trusses when the simplest avenue is when trusses are identified with a fire under them then all members get out and fight the thing from the exterior.

Flashover occurs when the temperature within a room or space increases to a level that ignites all of the materials within. But there is a definite time line to this event. And there are telling cues upon arrival signaling that this event is forthcoming. Rollover is a 90% valid cue that flashover is imminent. We have encapsulated our fire fighters to such an extent that they have been denied many of their natural thermometers such as ears.

Firefighters can get lost in a closet if they are inexperienced. Too many however have gotten lost in areas where they should not have been. A commercial structure with a confirmed fire within creates many thousands of square feet of space, which can thwart the safety of fire fighters within. When units arrive and they report little or no smoke visible everyone should become more aware not more complacent. There needs to be someone or some company assigned to monitor conditions in these structures. Yes, many 90 times out of a hundred the job will not be anything but it's that ten times that make the difference. Furthermore no company should enter these structures without safety lines and escape routes or fall back positions. Also, we often don't use all of the tools at our disposal. A 1 ? or 1 ? handline has about a 40 foot reach while a 2 ? handline has a 100 foot reach. Do the numbers or set up unmanned monitor streams.

Too many Incident Commanders piecemeal help requests. A wise old chief taught me "you can always send them back if you don't need them, but you can't make them appear when you don't have them". This seems simple enough. The size up given is the first picture an IC has and they must act quickly if they are going to get ahead of the fire curve. For those who rely on mutual aid you have to know how long that help will take and limit your crew's involvement until the help arrives. The worst scenario has to be when rescues are needed and your are stretched to the absolute limit on manpower. There is no room for error and if your people get into trouble you have absolutely no resources to assist them. It's a question of risk versus gain where your personnel are the bet.

The question of RIT still perplexes many of us in the fire service. For some it's the panacea for aggressive behavior with limited manpower. There are some that post two fire fighters and refer to that a staging a RIT group. This is so far from the reality of the situation. I have had the distinct to train with the people in this country who are the absolute wizards of RIT. These are people from FDNY, Philly, Jersey City, Pittsburgh, Worcester, Providence, and LA County. We seem to learn something new each time we teach RIT HOT ops. A few common experiences seem to hold constant:

• The first crew has the responsibility of finding the victim/s, getting them on new air
• Assessing the situation for resource requirements
• Other units must provide handlines and equipment
• The first team will not be the team who brings you out
• You have 4 minutes to get the victim/s on fresh bottles
• The first crew should carry MINIMUM tools no more than lights, radios, camera, rope/tag lines and a few forcible entry tools