The Proto is a type of rebreather that was made by Siebe Gorman . It was an industrial breathing set and not suitable for diving. It was made from 1914 or earlier to the 1960s or later. (Distinguish from "Proton", which is another sort of Siebe Gorman rebreather). Also known as proto suits .
99-446: Its breathing bag was worn on the chest. It had one or two oxygen cylinders, across the lumbar part of the back: often one, but this image shows two. Its duration in use was one or two hours, dependent on the size of oxygen cylinder fitted. Its absorbent ( tradename Protosorb) was loose in the bottom of the breathing bag, restrained by a perforated cloth partition, and not in a canister. It had two wide breathing tubes running from
198-418: A fire shelter " and should be "...at least four times the maximum continuous flame height." However this figure only takes into account the effects of radiant heat and does not consider topography nor wind. Safety Zones can be natural features such as rock screes, meadows, and river bars; or human-made features such a parking lots or areas that have been cleared of vegetation through mechanical means. One of
297-580: A 10/14 shift, in which the day shift works ten hours and the night shift works 14 hours. Firefighting personnel are split up into alternating shifts. Usually, the 24-hour shifts are followed by two days off. The shift personnel arrive for roll call at a specified time, ready to complete a regular tour of duty. While on shift, the firefighter remains at the fire station unless relieved or assigned other duties. In fire fighting, there are also people designated as fire wardens, also known as chief officers. Their duties vary, some may ensure evacuation of that part of
396-550: A fire hazard, so the more successful applications have been for space-suits, fire-fighting and mine rescue. A liquid oxygen supply can be used for oxygen or mixed gas rebreathers. If used underwater, the liquid-oxygen container must be well insulated against heat transfer from the water. Industrial sets of this type may not be suitable for diving, and diving sets of this type may not be suitable for use out of water due to conflicting heat transfer requirements. The set's liquid oxygen tank must be filled immediately before use. Examples of
495-413: A fire in a cellar or an underground car park with only a few centimeters of visibility may require long reconnaissance to identify the source of the fire. The "reading" of a fire is the analysis by firefighters of indications of thermal events such as flashover , backdraft or smoke explosion . It is performed during reconnaissance and fire suppression maneuvers. The main signs are: Spraying water on
594-430: A fire. Water extinguishes a fire by cooling, which removes heat because of water’s ability to absorb massive amounts of heat as it converts to water vapor . Without heat, the fuel cannot keep the oxidizer from reducing the fuel in order to sustain the fire. Water also extinguishes a fire by smothering it. When water is heated to its boiling point, it converts to water vapor. When this conversion takes place, it dilutes
693-402: A fraction of a second. Additional risks of fire are the obscuring of vision due to smoke, potentially causing a fall or disorientation ; becoming trapped in a fire; and structural collapse . "Three hours of fighting a fire stiffens arteries and impairs cardiac function in firefighters" according to a study by Bo Fernhall, a professor in the department of kinesiology and community health in
792-417: A large range of options are available depending on the specific application and available budget. A diving rebreather is safety-critical life-support equipment – some modes of failure can kill the diver without warning, others can require immediate appropriate response for survival. A helium reclaim system (or push-pull system) is used to recover helium based breathing gas after use by the diver when this
891-404: A loop configured machine has two unidirectional valves so that only scrubbed gas flows to the patient while expired gas goes back to the machine. The anaesthetic machine can also provide gas to ventilated patients who cannot breathe on their own. A waste gas scavenging system removes any gasses from the operating room to avoid environmental contamination. One of the functions of a space suit
990-412: A low burning fire can be devastating as it will ignite all of the oxygen along the way. It can also be heard from miles away as it has a concussive blast that adds to the effect. Firefighters need to have extreme communication at all times on the fire ground as one broken window at the wrong time could seriously harm anyone operating on the building. Depending on the heat of the fire, burns can occur in
1089-437: A lower pressure in the suit which gives the wearer better freedom of movement. Submarines , underwater habitats , bomb shelters, space stations , and other living spaces occupied by several people over medium to long periods on a limited gas supply, are equivalent to closed circuit rebreathers in principle, but generally rely on mechanical circulation of breathing gas through the scrubbers. Firefighting Firefighting
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#17327838236571188-425: A minimum of two Fire Wardens per floor. In this example, their duties include investigating any fire alarms (see if there really is a fire and if so, its nature), ensuring the fire department is contacted, directing the evacuation of the facility, activating or delaying activation of fire suppression equipment such as halon and sprinklers (delayed in case of a false alarm), meeting the fire department and taking them to
1287-550: A naturally hypoxic environment. They need to be lightweight and to be reliable in severe cold including not getting choked with deposited frost. A high rate of system failures due to extreme cold has not been solved. Breathing pure oxygen results in an elevated partial pressure of oxygen in the blood: a climber breathing pure oxygen at the summit of Mount Everest has a greater oxygen partial pressure than breathing air at sea level. This results in being able to exert greater physical effort at altitude. The exothermic reaction helps keep
1386-495: A naturally occurring element. Occupational exposures to silica dust can cause silicosis , lung cancer, pulmonary tuberculosis, airway diseases, and some additional non-respiratory diseases. Inhalation of asbestos can result in various diseases including asbestosis , lung cancer, and mesothelioma . Sources of metals exposure include burnt or melted electronics, cars, refrigerators, stoves, etc. Fire debris cleanup workers may be exposed to these metals or their combustion products in
1485-435: A number of hoses and electrical cables twisted together and deployed as a unit. This is extended to the divers through the diver umbilicals. The accommodation life support system maintains the chamber environment within the acceptable range for health and comfort of the occupants. Temperature, humidity, breathing gas quality, sanitation systems, and equipment function are monitored and controlled. An atmospheric diving suit
1584-454: A pendulum rebreather. Breathing hoses can be tethered down to a diver's shoulders or ballasted for neutral buoyancy to minimise loads on the mouthpiece. A mouthpiece with bite-grip , an oro-nasal mask , a full-face mask , or a sealed helmet is provided so that the user can breathe from the unit hands-free. A store of oxygen, usually as compressed gas in a high pressure cylinder, but sometimes as liquid oxygen , that feeds gaseous oxygen into
1683-422: A plan for the building that provides information about structures, firefighter hazards, and in some cases the most appropriate strategies and tactics for fighting a fire in that context. There are four elements needed to start and sustain a fire and/or flame: temperature, a fuel , an oxidizing agent (oxygen), and a chemical reaction. A fire can be extinguished by taking away any of the four components. The fuel
1782-485: A popular fire engine that was essentially a rectangular box on wheels filled using a bucket brigade to provide a reservoir while hand-powered pumps supplied sufficient water pressure to douse fires at a distance. Ancient Rome did not have municipal firefighters. Instead, private individuals relied on their slaves or supporters to take action. They would not only form bucket brigades or attempt to smother smaller fires, but would also demolish or raze nearby buildings to slow
1881-401: A portable apparatus carried by the user. The same technology on a vehicle or non-mobile installation is more likely to be referred to as a life-support system . Rebreather technology may be used where breathing gas supply is limited, such as underwater, in space, where the environment is toxic or hypoxic (as in firefighting), mine rescue, high-altitude operations, or where the breathing gas
1980-425: A wide enough bore to minimise flow resistance at the ambient pressure in the operational range for the equipment, are usually circular in cross section, and may be corrugated to let the user's head move about without the tube collapsing at kinks. Each end has an airtight connection to the adjacent component, and they may contain a one-way valve to keep the gas circulating the right way in a loop system. Depending on
2079-448: Is a profession aimed at controlling and extinguishing fire . A person who engages in firefighting is known as a firefighter or fireman. Firefighters typically undergo a high degree of technical training. This involves structural firefighting and wildland firefighting . Specialized training includes aircraft firefighting , shipboard firefighting, aerial firefighting , maritime firefighting, and proximity firefighting. Firefighting
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#17327838236572178-534: Is a common misconception. In 1833 fire insurance companies in London merged to form The London Fire Company Establishment. Steam-powered apparatuses were first introduced in the 1850s, allowing a greater quantity of water to be directed onto a fire; in the early 1930s they were superseded by versions powered by an internal combustion engine. In World War II the Auxiliary Fire Service , and later
2277-504: Is a dangerous profession due to the toxic environment created by combustible materials , with major risks being smoke, oxygen deficiency , elevated temperatures, poisonous atmospheres, and violent air flows. To combat some of these risks, firefighters carry self-contained breathing apparatus . Additional hazards include falls – a constant peril while navigating unfamiliar layouts or confined spaces amid shifting debris under limited visibility – and structural collapse that can exacerbate
2376-435: Is a small one-man articulated submersible of roughly anthropomorphic form, with limb joints which allow articulation under external pressure while maintaining an internal pressure of one atmosphere. Breathing gas supply may be surface supplied by umbilical, or from a rebreather carried on the suit. An emergency gas supply rebreather may also be fitted to a suit with either surface supply or rebreather for primary breathing gas. As
2475-534: Is an engineering control that can be used to avoid or minimize exposure to hazardous substances. When ventilation is insufficient or dust cannot be avoided, personal protective equipment such as N95 respirators can be used. The first step in a firefighting operation is reconnaissance to search for the origin of the fire (which may not be obvious for an indoor fire, especially if there are no witnesses), to identify any specific risks, and to detect possible casualties. An outdoor fire may not require reconnaissance, but
2574-604: Is based on the type of fires that the extinguisher is more suitable for. In the United States, the types of fire are described by the National Fire Protection Association . The earliest known firefighters were in the city of Rome. In 60 A.D., emperor Nero established a Corps of Vigils ( Vigiles ) to protect Rome after a disastrous fire. It consisted of 7,000 people equipped with buckets and axes who fought fires and served as police. In
2673-402: Is calcium hydroxide, which is relatively cheap and easily available. Other components may be present in the absorbent. Sodium hydroxide is added to accelerate the reaction with carbon dioxide. Other chemicals may be added to prevent unwanted decomposition products when used with standard halogenated inhalation anaesthetics. An indicator may be included to show when carbon dioxide has dissolved in
2772-420: Is important, such as in space stations and space suits. Lithium peroxide also replenishes the oxygen during the scrubbing reaction. Another method of carbon dioxide removal occasionally used in portable rebreathers is to freeze it out, which is possible in a cryogenic rebreather which uses liquid oxygen. The liquid oxygen absorbs heat from the carbon dioxide in a heat exchanger to convert the oxygen to gas, which
2871-613: Is less of a problem. The Soviet IDA71 rebreather was also manufactured in a high altitude version, which was operated as an oxygen rebreather. Anaesthetic machines can be configured as rebreathers to provide oxygen and anaesthetic gases to a patient during surgery or other procedures that require sedation. An absorbent is present in the machine to remove the carbon dioxide from the loop. Both semi-closed and fully closed circuit systems may be used for anaesthetic machines, and both push-pull (pendulum) two directional flow and one directional loop systems are used. The breathing circuit of
2970-427: Is more economical than losing it to the environment in open circuit systems. The recovered gas is passed through a scrubber system to remove carbon dioxide, filtered to remove odours, and pressurised into storage containers, where it may be mixed with oxygen to the required composition for re-use, either immediately, or at a later date. The life support system provides breathing gas and other services to support life for
3069-417: Is not welcome in hot industrial situations including in deep mines. It was used by firefighters and by rescuers in coalmines , long before open-circuit industrial breathing sets based on the aqualung became common. It appeared in news images of coalmine rescue squads. In 1908 the apparatus was chosen for use by rescuers from the newly formed Howe Bridge Mines Rescue Station . These sets were used in
Siebe Gorman Proto - Misplaced Pages Continue
3168-695: Is specially enriched or contains expensive components, such as helium diluent or anaesthetic gases. Rebreathers are used in many environments: underwater, diving rebreathers are a type of self-contained underwater breathing apparatus which have provisions for both a primary and emergency gas supply. On land they are used in industrial applications where poisonous gases may be present or oxygen may be absent, firefighting , where firefighters may be required to operate in an atmosphere immediately dangerous to life and health for extended periods, in hospital anaesthesia breathing systems to supply controlled concentrations of anaesthetic gases to patients without contaminating
3267-399: Is sufficient to freeze the carbon dioxide. This process also chills the gas, which is sometimes, but not always, desirable. A breathing hose or sometimes breathing tube on a rebreather is a flexible tube for breathing gas to pass through at ambient pressure. They are distinguished from the low-, intermediate-, and high-pressure hoses which may also be parts of rebreather apparatus. They have
3366-427: Is the earliest type of rebreather and was commonly used by navies for submarine escape and shallow water diving work, for mine rescue, high altitude mountaineering and flight, and in industrial applications from the early twentieth century. Oxygen rebreathers can be remarkably simple and mechanically reliable, and they were invented before open-circuit scuba. They only supply oxygen, so there is no requirement to control
3465-407: Is the substance being oxidized or burned in the combustion process. The most common fuels contain carbon along with combinations of hydrogen and oxygen. Heat is the energy component of a fire. When it comes into contact with a fuel, it provides the energy necessary for ignition, causes the continuous production and ignition of fuel vapors or gases so that the combustion reaction can continue, and causes
3564-522: Is then available again to react with more carbonic acid. 100 grams (3.5 oz) of this absorbent can remove about 15 to 25 litres (0.53 to 0.88 cu ft) of carbon dioxide at standard atmospheric pressure. This process also heats and humidifies the air, which is desirable for diving in cold water, or climbing at high altitudes, but not for working in hot environments. Other reactions may be used in special circumstances. Lithium hydroxide and particularly lithium peroxide may be used where low mass
3663-438: Is time to withdraw firefighters from a fire, and react calmly in emergency situations. The chief officer must direct the activities of a fire department and supervise all firefighting activities, requiring extensive knowledge of city layouts, the location of streets, fire hydrants and fire alarm boxes, and the principal buildings. A chief officer must be familiar with sources of fires, including explosives, hazardous chemicals, and
3762-427: Is to provide the wearer with breathing gas. This can be done via an umbilical from the life-support systems of the spacecraft or habitat, or from a primary life support system carried on the suit. Both of these systems involve rebreather technology as they both remove carbon dioxide from the breathing gas and add oxygen to compensate for oxygen used by the wearer. Space suits usually use oxygen rebreathers as this allows
3861-421: Is usually necessary to eliminate the metabolic product carbon dioxide (CO 2 ). The breathing reflex is triggered by CO 2 concentration in the blood, not by the oxygen concentration, so even a small buildup of CO 2 in the inhaled gas quickly becomes intolerable; if a person tries to directly rebreathe their exhaled breathing gas, they will soon feel an acute sense of suffocation , so rebreathers must remove
3960-542: Is wasted. Continued rebreathing of the same gas will deplete the oxygen to a level which will no longer support consciousness, and eventually life, so gas containing oxygen must be added to the breathing gas to maintain the required concentration of oxygen. However, if this is done without removing the carbon dioxide, it will rapidly build up in the recycled gas, resulting almost immediately in mild respiratory distress, and rapidly developing into further stages of hypercapnia , or carbon dioxide toxicity. A high ventilation rate
4059-778: The London Blitz , 700 fire men and 20 fire women, as known during the time period died as a result of heavy bombing, 91 of these perished at the same time defending London. By the end of the London Blitz, 327 firefighters had lost their lives. In January 1608, a fire destroyed many colonists' provisions and lodgings in Jamestown, Virginia . By the mid-1600s, Boston , New Amsterdam (later New York City ), and Philadelphia were all plagued by fires, and volunteer fire brigades began to form. In 1736, Benjamin Franklin founded
Siebe Gorman Proto - Misplaced Pages Continue
4158-601: The National Fire Service , were established to supplement local fire services. Before 1938, there was no countrywide standard for firefighting terms, procedures, ranks, or equipment (such as hose couplings). In the month of August in 1939 with war looking very possible the Fire Service's act of 1938 came into effect. This unified Great Britain's fire service and prepared them for the German war machine. During
4257-530: The Union Fire Company in Philadelphia, which became the standard for volunteer fire organizations. These firefighters had two critical tools: salvage bags and so-called bed keys. Salvage bags were used to quickly collect and save valuables, and bed keys were used to separate the wooden frame of a bed (often the most valuable item in a home at the time) into pieces for safe and rapid removal from
4356-419: The decompression status of the diver and record the dive profile . As a person breathes, the body consumes oxygen and produces carbon dioxide . Base metabolism requires about 0.25 L/min of oxygen from a breathing rate of about 6 L/min, and a fit person working hard may ventilate at a rate of 95 L/min but will only metabolise about 4 L/min of oxygen. The oxygen metabolised is generally about 4% to 5% of
4455-414: The 3rd century B.C., an Alexandrian Greek named Ctesibius made a double force pump called a siphona . As water rose in the chamber, it compressed the air inside, which forced the water to eject in a steady stream through a pipe and nozzle. In the 16th century, syringes were also used as firefighting tools, the larger ones being mounted on wheels. Another traditional firefighting method that survived
4554-447: The CO 2 in a component known as a carbon dioxide scrubber . By adding sufficient oxygen to compensate for the metabolic usage, removing the carbon dioxide, and rebreathing the gas, most of the volume is conserved. The endurance of a rebreather, the duration for which it can be safely and comfortably used, is dependent on the oxygen supply at the oxygen consumption rate of the user, and
4653-654: The College of Applied Health Sciences, and Gavin Horn, director of research at the Illinois Fire Service Institute. The conditions (observed in healthy male firefighters) are "also apparent found in weightlifters and endurance athletes..." Once extinguished, fire debris cleanup poses several safety and health risks for workers. Many hazardous substances are commonly found in fire debris. Silica can be found in concrete, roofing tiles, or it may be
4752-422: The London fire brigade from the 1950s till the early to late 1970s, when these rebreathers were replaced by compressed air sets which use a cylinder strapped to the back of the firefighter and the air fed through a hose to the firefighter's full face mask: this is their current type of breathing apparatus. Some had a whistle that automatically sounded when its oxygen cylinder pressure became low in use. This feature
4851-1209: The air or on their skin. These metals may include beryllium , cadmium , chromium , cobalt , lead , manganese , nickel , and many more. Polyaromatic hydrocarbons (PAHs), some of which are carcinogenic, come from the incomplete combustion of organic materials and are often found as a result of structural and wildland fires. Safety hazards of fire cleanup include the risk of reignition of smoldering debris, electrocution from downed or exposed electrical lines or in instances where water has come into contact with electrical equipment. Structures that have been burned may be unstable and at risk of sudden collapse. Standard personal protective equipment for fire cleanup include hard hats , goggles or safety glasses, heavy work gloves, earplugs or other hearing protection , steel-toe boots , and fall protection devices. Hazard controls for electrical injury include assuming all power lines are energized until confirmation they are de-energized, and grounding power lines to guard against electrical feedback, and using appropriate personal protective equipment. Proper respiratory protection can protect against hazardous substances. Proper ventilation of an area
4950-603: The air that the staff breathe, and at high altitude, where the partial pressure of oxygen is low, for high altitude mountaineering. In aerospace there are applications in unpressurised aircraft and for high altitude parachute drops, and above the Earth's atmosphere, in space suits for extra-vehicular activity . Similar technology is used in life-support systems in submarines, submersibles, atmospheric diving suits , underwater and surface saturation habitats, spacecraft, and space stations, and in gas reclaim systems used to recover
5049-419: The ambient pressure breathing volume components, usually called the breathing loop in a circulating flow rebreather, and the make-up gas supply and control system. The counterlung is an airtight bag of strong flexible material that holds the volume of the exhaled gas until it is inhaled again. There may be a single counterlung, or one on each side of the scrubber, which allows a more even flow rate of gas through
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#17327838236575148-441: The ambient pressure breathing volume, either continuously, or when the user operates the oxygen addition valve, or via a demand valve in an oxygen rebreather, when the volume of gas in the breathing circuit becomes low and the pressure drops, or in an electronically controlled mixed gas rebreather, after a sensor has detected insufficient oxygen partial pressure, and activates a solenoid valve. Valves are needed to control gas flow in
5247-417: The breathing bag to either a strapped-in mouthpiece (used with goggles) or an industrial-type fullface mask known as a Vistarama face mask, with a curved window and an inner orinasal mask . The canister seen on the front of the bag was to cool the gas in circuit, as the absorbent gets warm as it absorbs carbon dioxide , and that warming of the gas in circuit is welcome when scuba diving in cold water, but
5346-470: The breathing gas is a mixture of oxygen and metabolically inactive diluent gas. These can be divided into semi-closed circuit, where the supply gas is a breathable mixture containing oxygen and inert diluents, usually nitrogen and helium, and which is replenished by adding more of the mixture as the oxygen is used up, sufficient to maintain a breathable partial pressure of oxygen in the loop, and closed circuit rebreathers, where two parallel gas supplies are used:
5445-692: The breathing volume, and gas feed from the storage container. They include: Oxygen sensors may be used to monitor partial pressure of oxygen in mixed gas rebreathers to ensure that it does not fall outside the safe limits, but are generally not used on oxygen rebreathers, as the oxygen content is fixed at 100%, and its partial pressure varies only with the ambient pressure. Re breathers can be primarily categorised as diving rebreathers, intended for hyperbaric use, and other rebreathers used at pressures from slightly more than normal atmospheric pressure at sea level to significantly lower ambient pressure at high altitudes and in space. Diving rebreathers must often deal with
5544-512: The building for which they are responsible; others may be responsible for fire control in a particular area, direct a crew in the suppression of forest fires, or function as fire patrolmen in a logging area. The chief officer is in charge of their firefighters during fires or emergencies, and is expected to command and control the overall situation while effectively combating a fire or other emergency. Chief officers must be able to evaluate their firefighters, use sound judgement when deciding when it
5643-406: The capacity of the scrubber to remove carbon dioxide at the rate it is produced by the user. These variables are closely linked, as the carbon dioxide is a product of metabolic oxygen consumption , though not the only product. This is independent of depth, except for work of breathing increase due to gas density increase. There are two basic arrangements controlling the flow of breathing gas inside
5742-401: The carbon dioxide absorbent: 4KO 2 + 2CO 2 = 2K 2 CO 3 + 3O 2 . A small volume oxygen cylinder is needed to fill and purge the loop at the start of use. This technology may be applied to both oxygen and mixed gas rebreathers, and can be used for diving and other applications. Potassium superoxide reacts vigorously with liquid water, releasing considerable heat and oxygen, and causing
5841-401: The ceiling in short pulses of a diffused spray (e.g., a cone with an opening angle of 60°) can be undertaken to test the heat of smoke: If the temperature is moderate, the water falls down in drops with a sound like rain; if the temperature is high, the water vaporizes with a hiss—the sign of a potentially extremely dangerous impending flashover. Ideally, part of reconnaissance is consulting
5940-438: The combustion qualities of materials in buildings, homes, and industrial plants . In certain jurisdictions, civilians can get certified to be a Fire Warden, and some cities require certain types of buildings, such as high rises, to have a certain number of Fire Wardens. For example, the city of Houston in the United States requires every tenant in a high-rise to have at least one Fire Warden for every 7500 sq. ft. occupied, and
6039-416: The complications of avoiding hyperbaric oxygen toxicity, while normobaric and hypobaric applications can use the relatively trivially simple oxygen rebreather technology, where there is no requirement to monitor oxygen partial pressure during use providing the ambient pressure is sufficient. Rebreathers can also be subdivided by functional principle as closed circuit and semi-closed circuit rebreathers. This
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#17327838236576138-473: The diluent, to provide the bulk of the gas, and which is recycled, and oxygen, which is metabolically expended. Carbon dioxide is considered a waste product, and in a correctly functioning rebreather, is effectively removed when the gas passes through the scrubber. There have been a few rebreather designs (e.g. the Oxylite) which use potassium superoxide , which gives off oxygen as it absorbs carbon dioxide, as
6237-485: The district or city street system they will have to negotiate in order to perform their duties. They must meet minimum physical fitness standards and learn various firefighting duties within a reasonable period Examples are: Specialized areas of operations may require subject-specific training. Examples are: Full-time career firefighters typically follow a 24-hour shift schedule, although some fire departments work 8- or 12-hour shifts. Australian firefighters work
6336-439: The diver continues to inhale. Oxygen can also be added manually by a button which activates the demand valve. Some simple oxygen rebreathers had no automatic supply system, but only the manual feed valve, and the diver had to operate the valve at intervals to refill the breathing bag as the volume of oxygen decreased below a comfortable level. All rebreathers other than oxygen rebreathers may be considered mixed gas rebreathers, as
6435-416: The exhaled gas is discharged directly into the environment. The purpose is to extend the breathing endurance of a limited gas supply, while also eliminating the bubbles otherwise produced by an open circuit system. The latter advantage over other systems is useful for covert military operations by frogmen , as well as for undisturbed observation of underwater wildlife. A rebreather is generally understood to be
6534-443: The fact that Rome had no fire department, by creating his own brigade—500 men strong—which rushed to burning buildings at the first cry of alarm. Upon arriving at the scene, however, the firefighters did nothing while Crassus offered to buy the burning building from the distressed property owner, at a miserable price. If the owner agreed to sell the property, his men would put out the fire; if the owner refused, then they would simply let
6633-584: The fire. The first American attempt at fire insurance failed after a large fire in Charlestown, Massachusetts in 1736. Later in 1740, Benjamin Franklin organized the Philadelphia Contributionship to provide fire insurance, which was more successful. The Contributionship adopted "fire marks" to easily identify insured buildings. Firefighting started to become formalized with rules for providing buckets, ladders, and hooks, and with
6732-719: The formation of volunteer companies. A chain of command was also established. A firefighter's goals are to save lives, protect property, and protect the environment. A fire can rapidly spread and endanger many lives, but with modern firefighting techniques, catastrophe can often be avoided. To prevent fires from starting, a firefighter's duties may include public education about fire safety and conducting fire inspections of locations to verify their adherence to local fire codes . Firefighting requires technical proficiency of operational tactics, equipment, and scene awareness. Firefighters must also have, or be able to acquire, knowledge of department organizations, operations, and procedures, and
6831-410: The gas composition other than removing the carbon dioxide. In some rebreathers the oxygen cylinder has oxygen supply mechanisms in parallel. One is constant flow ; the other is a manual on-off valve called a bypass valve; both feed into the same hose which feeds the counterlung. Others are supplied via a demand valve on the counterlung. This will add gas at any time that the counterlung is emptied and
6930-435: The granules by size, or by moulding granules at a consistent size and shape. Gas flow through the scrubber may be in one direction in a loop rebreather, or both ways in a pendulum rebreather. The scrubber canister generally has an inlet on one side and an outlet on the other side. A typical absorbent is soda lime , which is made up of calcium hydroxide Ca(OH) 2 , and sodium hydroxide NaOH. The main component of soda lime
7029-679: The immense heat generated by a fire, even without direct contact with the flames (direct flame impingement), such as conductive heat and radiant heat , can cause serious burns even from great distances. There are a number of comparably serious heat-related risks, such as burns from hot gases (e.g., air), steam, and hot and/or toxic smoke . Prolonged, intense exertion in hot environments also increases firefighters' risk for heat-related illnesses, such as rhabdomyolysis . Accordingly, firefighters are equipped with personal protective equipment (PPE) that includes fire-resistant clothing such as Nomex or polybenzimidazole fiber (PBI) and helmets that limit
7128-475: The inspired volume at normal atmospheric pressure , or about 20% of the available oxygen in the air at sea level . Exhaled air at sea level contains roughly 13.5% to 16% oxygen. The situation is even more wasteful of oxygen when the oxygen fraction of the breathing gas is higher, and in underwater diving, the compression of breathing gas due to depth makes the recirculation of exhaled gas even more desirable, as an even larger proportion of open circuit gas
7227-401: The intermediate reaction, the carbonic acid reacts exothermically with sodium hydroxide to form sodium carbonate and water: H 2 CO 3 + 2NaOH –> Na 2 CO 3 + 2H 2 O + heat. In the final reaction, the sodium carbonate reacts with the slaked lime (calcium hydroxide) to form calcium carbonate and sodium hydroxide: Na 2 CO 3 + Ca(OH) 2 –> CaCO 3 + 2NaOH. The sodium hydroxide
7326-435: The internal pressure is maintained at one atmosphere, there is no risk of acute oxygen toxicity. This is an underwater diving application, but has more in common with industrial applications than with ambient pressure scuba rebreathers. Different design criteria apply to SCBA rebreathers for use only out of the water: Mountaineering rebreathers provide oxygen at a higher concentration than available from atmospheric air in
7425-534: The large volumes of helium used in saturation diving . The recycling of breathing gas comes at the cost of technological complexity and specific hazards, some of which depend on the application and type of rebreather used. Mass and bulk may be greater or less than open circuit depending on circumstances. Electronically controlled diving rebreathers may automatically maintain a partial pressure of oxygen between programmable upper and lower limits, or set points, and be integrated with decompression computers to monitor
7524-505: The location of the alarm or to the fire past any security or locked doors, and, if necessary, fighting the fire until the fire department arrives. The U.S. Forest Service publishes guidelines for the minimum distance a firefighter should be from a flame. As stated in the National Wildfire Coordinating Group's Incident Response Pocket Guide: "A safety zone is an area where a firefighter can survive without
7623-458: The major hazards associated with firefighting operations is the toxic environment created by combusting materials. The four major hazards are: To deal with such hazards, firefighters carry a self-contained breathing apparatus (SCBA; an open-circuit positive pressure system) to prevent smoke inhalation. These are not oxygen tanks (oxygen as a powerful fire accelerant would represent a grave risk when combined with virtually anything combustible in
7722-450: The oxygen in the air above the fire, thus removing one of the elements that the fire requires to burn. This can also be done with foam. Another way to extinguish a fire is fuel removal. This can be accomplished by stopping the flow of liquid or gaseous fuel, by removing solid fuel in the path of a fire, or by allowing the fire to burn until all the fuel is consumed, at which point the fire will self-extinguish. One final extinguishing method
7821-400: The personnel under pressure in the accommodation chambers and closed diving bell. It includes the following components: The life support system for the bell provides and monitors the main supply of breathing gas, and the control station monitors the deployment and communications with the divers. Primary gas supply, power and communications to the bell are through a bell umbilical, made up from
7920-402: The photo, benefit from easier field repair if a tear or hole while helical corrugations allow efficient drainage after cleaning. Breathing hoses are usually long enough to connect the apparatus to the user's head in all attitudes of their head, but should not be unnecessarily long, which will cause additional weight, hydrodynamic drag , risk snagging on things, or contain excess dead space in
8019-468: The presence of fire) but use compressed air in a similar manner to SCUBA diving gear . A firefighter's SCBA usually hold 30 to 45 minutes of air, depending on the size of the tank and the rate of consumption during strenuous activities. While this gear helps to eliminate the risks, firefighters are still exposed to smoke, toxic dust, fumes and radiation that have contributed to firefighters being 14% more likely to develop cancer. Obvious risks associated with
8118-470: The problems encountered in a toxic environment. The first step in a firefighting operation is reconnaissance to search for the origin of the fire and to identify the specific risks. Fires can be extinguished by water, fuel or oxidant removal, or chemical flame inhibition; though, because fires are classified depending on the elements involved, such as grease, paper, electrical, etcetera, a specific type of fire extinguisher may be required. The classification
8217-418: The rebreather, known as the pendulum and loop systems. In the pendulum configuration, the user inhales gas from the counterlung through a breathing hose, and exhaled gas returns to the counterlung by flowing back through the same hose. The scrubber is usually between the breathing hose and the counterlung bag, and gas flow is bi-directional. All of the flow passages between the user and the active absorbent in
8316-467: The scrubber are dead space – volume containing gas which is rebreathed without modification by the rebreather. The dead space increases as the absorbent is depleted. Breathing hose volume must be minimised to limit dead space. In the loop configuration, the user inhales gas through one hose, and exhales through a second hose. Exhaled gas flows into the scrubber from one side, and exits at the other side. There may be one large counterlung, on either side of
8415-621: The scrubber contents from freezing, and helps reduce heat loss from the user. Both chemical and compressed gas oxygen have been used in experimental closed-circuit oxygen systems – the first on Mount Everest in 1938 . The 1953 expedition used closed-circuit oxygen equipment developed by Tom Bourdillon and his father for the first assault team of Bourdillon and Evans ; with one "dural" 800l compressed oxygen cylinder and soda lime canister (the second (successful) assault team of Hillary and Tenzing used open-circuit equipment). Similar requirement and working environment to mountaineering, but weight
8514-463: The scrubber, or two smaller counterlungs, one on each side of the scrubber. Flow is in one direction, enforced by non-return valves, which are usually in the breathing hoses where they join the mouthpiece. Only the flow passage in the mouthpiece before the split between inhalation and exhalation hoses is dead space, and this is not affected by hose volume. There are some components that are common to almost all personal portable rebreathers. These include
8613-436: The scrubber, which can reduce work of breathing and improve scrubber efficiency by a more consistent dwell time . The scrubber is a container filled with carbon dioxide absorbent material, mostly strong bases , through which the exhaled gas passes to remove the carbon dioxide. The absorbent may be granular or in the form of a moulded cartridge. Granular absorbent may be manufactured by breaking up lumps of lime and sorting
8712-442: The service, they may be made of a flexible polymer, an elastomer , a fibre or cloth reinforced elastomer, or elastomer covered with a woven fabric for reinforcement or abrasion resistance. If the woven layer is bonded to the outside surface it protects the rubber from damage from scrapes but makes it more difficult to wash off contaminants. Breathing hoses typically come in two types of corrugation. Annular corrugations, as depicted in
8811-518: The spread of the fire. However, there is no mention of fires being extinguished, rather they were contained and burned themselves out. Ancient Rome did not have an organized firefighting force until the Vigiles were formed during the reign of Augustus . The first ever Roman fire brigade was created by Marcus Licinius Crassus . Fires were almost a daily occurrence in Rome, and Crassus took advantage of
8910-423: The start of the 1800s, insured buildings were identified with a badge or mark indicating that they were eligible for a company's firefighting services. It is a common belief that buildings not insured with a particular company were left by its firefighters to burn, unless they happened to be adjacent to an insured building, in which case it was often in the company's interest to prevent the fire from spreading. This
9009-652: The structure burn to the ground. After buying many properties this way, he rebuilt them, and often leased the properties to their original owners or new tenants. Prior to the Great Fire of London in 1666, some parishes in the UK had begun to organize rudimentary firefighting crews. After the Great Fire, Nicholas Barbon introduced the first fire insurance. In order to reduce insurance costs, Barbon also formed his own fire brigade , and other companies followed suit. By
9108-511: The transmission of heat towards the body. No PPE, however, can completely protect the user from the effects of all possible fire conditions. Heat can cause flammable liquid contained in tanks to explode violently, producing what is called a BLEVE (boiling liquid expanding vapor explosion). Some chemical products such as ammonium nitrate fertilizers can also explode, potentially causing physical trauma from blast or shrapnel injuries. Sufficient heat causes human flesh to burn as fuel, or
9207-416: The type include: A cryogenic rebreather removes the carbon dioxide by freezing it out in a "snow box" by the low temperature produced as liquid oxygen evaporates to replace the oxygen used. This may be compared with some applications of open-circuit breathing apparatus: The widest variety of rebreather types is used in diving, as the consequences of breathing under pressure complicate the requirements, and
9306-421: The vaporization of solid and liquid fuels. The resulting self-sustained chemical chain reaction is complex and requires fuel, an oxidizer, and heat energy to come together in a very specific way. An oxidizing agent is a material or substance that will release gases, including oxygen, when the proper conditions exist. It is crucial to the sustainment of a flame or fire. Using water is one common method to extinguish
9405-425: The water of the soda lime and formed carbonic acid, changing the pH from basic to acid, as the change of colour shows that the absorbent has reached saturation with carbon dioxide and must be changed. The carbon dioxide combines with water or water vapor to produce a weak carbonic acid: CO 2 + H 2 O –> H 2 CO 3 . This reacts with the hydroxides to produce carbonates and water in an exothermic reaction. In
9504-414: The water within to boil, leading to potentially severe medical problems. Furthers risks include the occurrences of backdrafts . Backdrafts occur when there is a large amount of oxygen introduced to an oxygen-depleted fire. If a fire is compartmentalized and most or all of the oxygen has been burned up, there is a high risk of backdraft if something such as a window or door is opened. Introducing oxygen to
9603-452: The wearer. The reducing valve was of the constant feed type. Breathing bag A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. Oxygen is added to replenish the amount metabolised by the user. This differs from open-circuit breathing apparatus, where
9702-558: Was introduced following the death, in January 1958, of two London firemen at the fire that occurred at the Smithfield Central Meat Market in central London. The first version was designed by Fleuss and Davis in about 1906-1910. It had equal balance back and front of the wearer, and avoided projections on the back that could catch when crawling through holes. The more vulnerable parts were in front in sight of
9801-533: Was the bucket brigade, involving two lines of people formed between the water source and the fire. Typically, men in one of the lines would pass along the full buckets of water toward the fire while in the other line women and children would pass back the empty buckets to be refilled. In the 17th century the first "fire engines" were made, notably in Amsterdam. In 1721, the English inventor Richard Newsham made
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