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A Brief Overview of the Current Knowledge of Fire

A paper I present for your examination wherein I provide an overview of the mechanisms of fire, how fires in buildings proceed, methods for suppressing fire and designs to reduce the risk of fires.  I present this paper for the approval of the Port-a-Lucine Society of Science as an examination of the current state of knowledge of matters pertaining to fire.

Mechanisms of Fire

For fire to occur three requirements must be air, heat and combustible material sometimes known as fuels.  In most cases for a fire to start air and a combustible material must be present and an external source of fire must be applied.  In a few cases the combustible material may also be the source of heat.  I have found by experimentation that under the right conditions and when soaked in the right chemicals a piece of cloth, such as an oily rag, may spontaneously ignite.  I suggest that this may explain a number of fires in the laboratories of my eminent friends that they have previously been unable to explain without blaming unseen enemies or the Inquisition.

There are three types of fuels commonly found in fires.  Tinder is small sources such as the remnants of pipe smoking, paper, textiles, hair and oil.  Kindling will ignite and burn under the influence of tinder and act as a small source for the continuing fire.  Kindling primarily includes small pieces of wood.  Bulk fuels are heavier pieces of wood such as joists and rafters in buildings; baled combustible materials such as rolls of cloth; and books.

Building Fires

Fires in buildings are progressive.  Most start in small, localised spaces, from a single source of ignition.  They frequently smoulder for some time, undiscovered, gradually building up till they involve the immediate space.  If they remain unchecked they spread to adjacent parts of the building.  If they continue they may spread to adjacent buildings and surroundings as happened during conflagrations that have destroyed numerous settlements from the smallest hamlet to the largest city.

The usual ignition sources are small and go unnoticed.  By studying records compiled by officials of state in Lamordia, Dementlieu, Mordent and Falkovnia I have found that cooking fires, smoking, heating fires and the careless handling of candles are the three most common causes of building fires in that order in those countries.

The majority of deaths from fires result from domestic fires at night.  One of the most common causes of fatal fires is people who fall asleep while smoking their pipe in the bed chamber and thus immolate themselves.  These fires account for very little of the cost of damage done by fire.  The major costs result from fires in warehouses and other commercial buildings where a fire can destroy a significant value of goods if it is not extinguished promptly.

There are a number of causes that may result in a building fire starting with multiple points of ignition.  Some fires begin with the ignition of a highly spread, highly flammable material such as spilt oil or the ignition of a build up of gas from either natural sources or as a result of an industrial process under or in a building.   In experiments I have found that sometime powders, such as the dust from corn found in buildings used to store corn after harvesting, may act like a gas and ignite explosively.

The second cause of multiple points of fire is the deliberate starting of a number of fires in an attempt to destroy a building or harm its inhabitants.  This form of attack is called arson in law and is looked on as a most heinous crime.  An arsonist by using multiple sources of fire can increase the likelihood of success of their attack.  The multiple points of origin of the fire however provide strong evidence of the arsonists activities to anyone experienced in examining the remains of a burnt building.

Building fires have four phases.  During the first phase, which lasts from a few seconds to several hours ignition occurs.  The second phase, lasts around ten minutes in most fires.  During this phase the fire spreads and grows.  It is unusual for bulk fuels, especially building materials, to be ignited during the first two phases of a fire.  The second phase culminates in flashover and it then moves into the third phase.  This lasts for around forty minutes and sees the fire build to its peak.  I have measured temperatures as high as 960ºR (1200°C) during this phase.  During the fourth phase the fire declines as it exhausts its sources of fuel.  Its temperature falls by about half for each hour that passes.

Design of Buildings

Many countries currently do not design with any consideration to fire.  Virtually all older cities are veritable fire traps with buildings too close together allowing fire to rapidly spread from one building to another.

Architects in the Society of Port-a-Lucine Architecture (SPA) have, since the great fire, worked with members of the Port-a-Lucine Society of Science to develop a method for the design of buildings to prevent a similar fire in future.  The Guild of Masons in Lamordia has also been active in this area but has come to a very different solution for the same problem.   Which of these philosophies will ultimately prevail will only be determined by time.

The Dementlieu method relies on confining a fire so that it remains within the building.  After consideration of conflagrations it was decided that this would be the best practice to prevent a disaster on a massive scale.  Roofs and walls are to be constructed of fireproof materials such as brick, stone and slate.  A buildings roof will be supported by heavy members that are unlikely to fail even after several hours of exposure to fire.  Buildings will be spaces so as to prevent flames and heat from openings such as windows allowing the fire to ignite nearby buildings.  The walls between adjoining buildings are to be solid from foundation to rooftop to prevent fires spreading from one to another.  Buildings will also be designed so that they will not easily catch fire if a nearby building is alight.  This will also be achieved using fireproof materials for the construction of the outside of the building.

The Lamordia rely on encouraging the fire, once it passes into the third phase to burn itself out as rapidly as possible while preventing it igniting nearby buildings.  To achieve this roof designs have been used in newer Lamordian settlements that cause the roof to collapse once the fire has taken hold.  This allows air to the fire encouraging it to burn more vigorously.  At the same time, as with Dementlieu design, fireproof materials are used on the outside of buildings to prevent them igniting even if burning embers land on them or they face a structure that is fully ablaze.

Both schools of design emphasise preventing other nearby buildings catching fire.  To this end in areas where buildings are closely packed a number of measures have been adopted that are common to both.

Where buildings adjoin each other, even where they share a common roof, the wall between them must be solid without any openings from the lowest point of the basement to the very top of the structure.  This prevents the spread of fire along the loft space in a series of buildings such as a row of craftsmen’s abodes as occurred in several fires in both Lamordia and Dementlieu.

Flammable materials are not used on the external surfaces of a building at all if it is within a yard of another building.  If it is separated by six yards from any other buildings it may have as much flammable material as its maker desires.  To achieve this thatched roofs have been abandoned in favour of the safer slate roofs and bricks are being used instead of wood for walls.

To protect those fighting a fire or attempting to escape from a building fire buildings are being constructed with vertical walls. They no longer increase their area by jutting into the space above the road with each storey.

The western nations, have seen a growth in the popularity of safer designs of cooking fires and heating fires in recent years and this will further reduce these as the sources of fires.

Other Types of Fire

A number of other types of fire present special dangers.  Forests in many lands are especially prone to forest fires during the dry summer months.   Heath and moorland fires affect others.  Natural fires are believed to mostly result from the action of lightning or careless people.  Peat bogs in Tepest and coal seams in Mordent have been known to burn for years underground if set alight.

There is little that can be done to control any of these fires unless they are discovered early in their life before they have spread beyond the capability of humankind to extinguish using beaters.  If they take hold and are not extinguished by rain they can do significant damage and destroy smaller settlements in their path.  It has been possible on a few occasions for the spread of such a fire to be controlled by the cutting of a wide firebreak ahead of the fire or around a threatened settlement.  To perform such a feat requires a huge effort by many people.

Methods of Fire Suppression

There are three methods to attack a fire and thus suppress it.  Each relies on attacking one of the fires three components.  An attack can either remove air, heat or combustible materials.

During the first and second phase a fire may easily be extinguished by smothering its source.  It is during these phase that the maximum opportunity for extinguishing a fire with the minimal damage to it and its contents exists.

The quantity of material ablaze and heat of the fire during the third phase make extinguishing it difficult.  However this can sometimes be achieved and it is often necessary to at least reduce the fires intensity in order that the rescue of people trapped in a building may be attempted or to prevent it spreading to adjacent buildings.  It is not uncommon to see more fire fighters damping down adjacent properties and using fire hooks to remove burning debris rather than fighting the fire itself.

Once the fourth phase is entered there is little chance of saving anything other than a building’s shell.  Valuable materials that have not been damaged by the fire itself have most likely been damaged by smoke or by water used to attempt to extinguish the fire.  Fire fighters continue to act to prevent the fire spreading to adjacent properties and to see that it doesn’t act as the source for another fire later.

When fighting fires a variety of devices and materials may be used.  Water and sand are both effective at extinguishing blazing materials.  Water is used by preference for most fire fighting due to its convenience but in the case of chemical fires, such as burning oil, sand is far more effective as the water doesn’t extinguish the flame.  Small fires may be extinguished by using wet cloths.  In most cases water and sand is delivered to the fire in buckets.  Experimentation has shown that it is most effective when applied to the base of the fire.

Fire hooks can be used to remove materials that are alight from a building without endangering those using them.  This may allow them to be more easily extinguished and to reduce the potential size of the fire by reducing its available fuel.  Fire hooks can also be used to remove small amounts of burning debris from other buildings to prevent them from spreading the fire.  In Vendel fire hooks are also used to encourage the collapse of burning buildings roofs to speed the fire.

Fire engines are maintained either by official organisations or companies in many larger cities.  They allow a quantity of fire fighting equipment and fire fighters to be arrive at a fire quickly.

Fire fighting pumps are a recent innovation.  Using manually operated pumps with connections to reservoirs of water attached to hoses allows a fire to be extinguished far more effectively.  Unfortunately they lack mobility and take up a lot of space in a building so few buildings have them.  Some innovators have gone one better and have created pump engines.  These consist of a pump mounted on a fire engine.  A hose is run to the nearest source of water and sprayed onto the fire through a second hose.

Sturdy boots, thick leather fireproof clothing and solid helmets are of use to those fighting fire.

A Note on Insurance and Fire Services

A  number of merchants are offering insurance against the results of fire along with other insurance.  Although this practice is seen by some as a form of gambling or extortion where it is properly operated it can provide a benefit to all those who subscribe to it.

In many cities Fire Services have established themselves.  These services charge individuals to extinguish fires at their property should a fire start.  Many services operate fire watchers who watch for fires from vantage points across the city or patrol their patrons properties when they are unoccupied at night.

impworks © Copyright Mark Caldwell 1996 - 2018