Thursday, November 21, 2013

FIRE PROTECTION IN BUILDING

It is  true that every building contains something which will easily catch fir  and it is practically  impossible  to eliminate completely the chances of fire in a building .  As a matter of fact, it is estimated that a fire breaks  out every 37 seconds each day in America  a nation fully advanced in   technology of building construction.  It is equally true the no building  material is fully fir-proof, Considering these facts,  the International Fire Prevention Congress passed a resolution in 1903 recommending the use of term fir-resisting in place of fir-proof as applied to the building  materials  and constructions.
 Thus, a fully fire-resistant building is fully  protected against any fire  which may occur in its contents.



 Following  facts in connection with the fire protection in buildings should  be remembered:
1) It is too expensive to make all the buildings fully protected  against fire.  As a matter of fact, the amount spent on  fire-resisting construction should be in relation to the reduction  in loss in case fir breaks out. The preventive measures include suitable planning’s, proper method of construction  and  The preventive  reduction in loss in case fire breaks out. The preventive measures include suitable planning’s, proper method of construction and  satisfactory means of escape.
2)  It does not necessarily follow  that a non-combustible material possesses more  power to resist fire. For instance, a timber post would resist fire in a better way than an unprotected R.S. joist.
3) It does not necessarily follow that a non-combustible material possesses more  The main purpose of making a building fire-resistant is the protection of life,  goods an activities  within the building.
4)  The  degree of fire resistance required will largely depend on the use of building. For  instance, a theatre or a town hall will demand greater degree of fire resistant resistance required will  largely depend on the use of building  . For instance, a theatre or a town hall will demand greater degree of  fire  resistant  construction than a warehouse or a go down.
5)  In case of fire-resistance required will largely depend on the use of building. For  instance, a  of consuming and destroying and the tragic part of it is that nothing is left to rise from the ashes except the fumes of smoke. The survivors of fire  are left to carry terribly the impact and impression of fire, both psychologically and physically. The provision of  suitable means of escape from fire should be made in relation to these dangers and the number of persons to be affected in fire-hazard. In order to reduce the chances of damage due to panic, the means of escape from fir afire should be located in such  a way that they remain unobstructed by smoke or fumes.  Reduce the chances of damage due to panic, the  means of escape from fire should be locate d in such a way  panic, the means of escape from fire should be located in such a way that they remain unobstructed by smoke or fumes. In  other words, the means of escape from fire should be easily accessible, unobstructed and clearly defined.
6) It is estimated that nearly 15000 people are killed by fire every year in our country. The  direct and indirect losses are estimated as more than 1000 cores and yet, there is no comprehensive regulation to insure fir prevention. 
7)  The experience the world  over had shown that if escape from a tall building  is not effected within 10 minutes or 15 minutes of the outbreak of fir, the temperatures as high as and dense poisonous smoke  fatally trap  the people within  the building. 
8)  It has also been seen that the fire-fighting equipment, normally available, like  snorkel, cannot go beyond 10 floors the highest of the turntable ladder reaches only up to  within the building 
9)  It had also been seen that the fire-fighting equipment, normally available, like  snorkel, cannot go beyond 10 floors  the highest of the turntable ladder reaches only up to 13 the floor.
In this chapter, some of the important aspects  of fire protection in  the building will be discussed.
CAUSES AND EFFECTS OF FIRE
 Following are the chief causes of fire in order of the toll or victims taken:
1)  Smoking in unauthorized places ad disregarding carelessly the lighted ends. Of cigarettes and matches;
2) Faulty workmanship with respect to the  electrical wiring; 
3)  Heating and cooking equipment;
4)  Children playing with matches;
5)  Open flames and sparks;
6)  Flammable liquids;
7)  Suspected arson;
8)  Suspected arson;
9)  Lighting; and
10)  Spontaneous combustion.
The home contains various different  materials and they produce different  gasses when ignited by fire. The effects of these gases are s follows ;;
1) Carbon monoxide : The gas hampers oxygen from reaching the brain. It is the most abundant of fire gases. It is invisible and odorless.
2)  Carbon  dioxide :  This gas affects the nervous system and it causes dioxins and pain in the respiratory system.
3)  Nitrogen dioxide :  This gas in extremely  toxic and it numbs oar deadens  the throat.
The human body can withstand temperatures  of only between and The smoke hampers vision and gases impair rational thought. In  many cases, a fire victim loses consciousness before he  had a chance to plan out an effective route to safety and thus, many people have  been killed by lack of clear thought rather than flames.
 The content of oxygen is normally 21 per cent in air. If  falls below  17 per cent during a fire, rational thought and muscle control become extremely difficult.
 When  the oxygen level falls below 6 per cent, the breathing stops and after about 4 minutes  to minutes without oxygen, the brain death occurs. 
 Following are some of the precautionary measures which can be taken to avoid or to minimize  the dangers of a fire;
1) Be sure that the cigarettes  and matches are thoroughly  extinguished before  throwing them in rubbish.
2)  Entrust the work of wiring and electrical installations to an expert.
3)  Evacuate  your home as soon as possible . Do not allow toxic  fumes to take control of your mind.
4)  Feel each door before you open it. If the handle of door is hot or if smoke  is seen coming from its bottom or sides, do not open the door. There are all the chances of meeting with a blast of fire  in such cases. 
5)  If there is smoke, crawl on your hands and knees  to safety. Heat rises to the ceiling and there is roughly a safety zone  between 3000 mm off the floor  and approximately  height of the door knob.
6) If your clothes catch on fire,  drop to the floor and roll to extinguish the flames.
7)  Never smoke in bed. A cigarette will continue to burn for about 24 minutes, if it is ignited and left alone. It takes only 10 minutes or 12 minutes, however with your evacuation plan, close every door behind you.
8)  Train your family members of staff members  for fighting a fire and acquaint them with the fire preventive measures.
FIRE HAZARDS
 The fire hazards are fo the following three types :
1.  Exposure  hazard
2. Internal hazard
3. Internal hazard
4.  Personal hazard.
 Each of the above type of fire hazard will now be briefly described. 
  1 Exposure hazard :  Sometimes a fire spreads  into a building through the open air from fire in other adjacent buildings or from across a road or other  divisions of the same building. The risk involved in such fire spreading is  known as the exposure  hazard.
2) Internal hazard :  This type f hazard concerns damage or destruction of the building itself and it si directly  related to the fire-load which, in turn, enables  the building to be graded when considered along with the duration of fire.
 3) Personal hazard :  The possibility of loss or damage to the life is referred to as the personal hazard and naturally  it is of permanent importance. The fire safety provision sshoudl be liberally provided  for this type of hazard and safe fire proof exits should be suitably accommodated in the design of building having more than one storey.

FIRE-LOAD
 The term fire-load is used to indicate the amount of heat liberated in kilojoules per squaremetre of floor area of any compartment by the combustion of the content o the building and any combustible part of the building itself.
 The fire-load is determined by multiplying the weights  of all combustible materials by their respective calorific  values and dividing by the floor area under consideration. For instance, suppose a section of building had the floor area of and let in contain N of  combustible material having calorific value of
  The fire-load  is used  for the  grading of occupancies and as per  the fire-load  divided  into the following three classes :
1. Low fire-load
2.  Moderate fir-load
3.  High fire-load .
Table shows the grading of occupancies by the fire-load . It may be noted that different materials having the same weight and the same calorific value may present different  hazards on account of  their other properties such as speed of burning rate .  different hazards on account of their other  properties such as speed of burning, rate of ignition and liberation of dangerous fumes. For assessing the fire grading, the materials are classified as non-hazardous  and extra hazardous by considering their following  characteristics :
1.  Difficulty ot extinguish,
2.  Explosive tendencies,
3.  Generation of intense heat when burning, high inflammability,
4.  Liability to extend the fire zone,
5.  Liability ot intensify a fire and
6.  Spontaneous  combustion tendencies.
In order to limit fire spread, the following factors  factors are to be carefully  be carefully considered:
 Extinguishing and warning of fire should be made in the building. These equipments should be located at such places that they are easily accessible and readily visible. 
2) Materials of construction:  The structural elements of the building such as floors, partitions, roofs, walls should be constructed of fire-resisting materials. In  relation ot fire, the building materials are classified as be constructed of fire-materials. IN  relation of building such as floors, partitions, roofs, walls, etc. Should be constructed  materials. iN relation  to fire building materials are classified as combustible  materials and non combustible materials. During fire, the combustible materials combine exothermically with oxygen resulting in evolution of lot of heat and giving rise to flame. The  materials. On the other hand, the noncombustible materials, during fire, are decomposed  wood  and wood
Combustible materials and non with oxygen resulting in evolution of lot of heat and giving  are decomposed by heat with absorption of heat endothermically or oxidized  fire, are decomposed by heat These materials are therefore damaged and decomposed when high temperatures are reached, but they do not contribute  to the growth or spread of fire. The stones, bricks, concrete, metal, do not contribute ot the growth or spread of fire. The stones, bricks, concrete, metal, glass, clay products,  during fire, are decomposed by heat with absorption of heat  heat endothermic ally or oxidized with negligible evolution of heat. These materials are therefore damaged and oxidized with negligible evolution of heat.  These materials are therefore damaged and decomposed when high temperatures are reached, but they do not contribute to the growth or spread of fire. The stones,  bricks, concrete, metal, glass, clay products, tec. Are the example of non-combustible  materials.
 Means of escape : The building should be provided with suitable means of escape when fire occurs. This  is of paramount consideration in the design of theatres.  Cinemas, town halls , factories ad similar either public buildings.  In the design of theatres,  cinemas, town halls, factories and similar other public buildings.  Such means of escape will  serve as easy access to the fire-men.
   The above issue had also special attention to the modern day multi-storied buildings.  In case there is a fire in a particular  storey, the exit provisions  should be such that the occupants of the floor immediately above  and below  that storey must find suitable safe exit in reasonable time. For this purpose, the size of corridor, width of staircase  and location of staircase should be suitably decided by keeping in view the safety requirements.
  The National Building Code had covered the topic of  the fire protection in detail and some of the important provisions  are s follows :
1.  A separate fire lift should be provided  for use of fire brigade in the event of a fire.
2.  Every tall building  should have a minimums of two staircases. 
3.  No revolving door should  be have a minimum of two staircases.
4.  No revolving door should be treated as exits except in residential and mercantile occupancies.
5. The lifts and escalators should  not  of buildings should  be  as follows:
6.  Residential , education institutional ad hazardous 
7.  Business  The openings such as doors and windows I n the  sufficiently protected by suitable measures so as limit fire spread,
8.  It is desirable to subdivide large buildings into small  compartments or blocks so as to reduce the chances of fire spread to the whole of building.
GRADING OF STARUCTURAL ELEMENTS AND BUILDINGS
  The fire –load  is  determined by multiplying weights off all combustible  materials by their respective calorific values and  and dividing by the floor area  under consideration,  For instance, suppose  a section of building had the floor  area of and let it contain of combustible material having calorific value contain combustible material having calorific  value of 
 The fire-load is used for the grading of occupancies and as per  the fire-load is divided into the following three classes:
1) Low fire-load
2)  Moderate fire-load
3)  High fir-load.
 Table shows the grading of occupancies by the fire –load , It may  be noted that  different materials having the dame weight  and the same calorific value may present for assessing the fire grading, the materials are dangerous fumes. For assessing the fire grading, the materials are classified as non-hazardous  hazardous and extra hazardous by considering their following characteristics:
1 difficulty to extinguish,
1) Explosive tendencies,
2)  Generation of intense heat when burning,
3)  High inflammability,
4)  Liability to extend the fire zone,
5)  Liability to intensify  a fire, and
6) Spontaneous combustion tendencies.
In order to limit fire spread, the following factors are  to be carefully considered:
  Fire fighting equipment : The provision  of suitable equipment for edetecting, extinguishing and warning fo fire should be made in the building.  These equipments should be  located at such places that they ar easily accessibly and readily visible.
4) Materials of construction : The  structural  elements of the building such as floors, partitions, roofs, walls, etc. Should  be constructed of fire-resisting materials. In relation t fie, the building materials are  classified as combustible materials and non combustible materials. During fire, the combustible materials combine exothermincally with oxygen resulting I evolution of lot fo heat ad giving rise to flame. The wood and wood products, fibreboards, strawboards, etc. Are the examples of combustible materials. On the other hand, the non-combustible materials, during fie, ar decomposed by heat with absorption of heat endothermically or oxidized with negligible evolution of heat. These materials are therefore damaged and decomposed when high temperatures are reached, are therefore damlaged and decomposed when high temperatures are reched, but they do not contribute  to the growth or spread of fire. The stones, bricks,,  co0ncrete, metal, glass, clay products, etc. Are the examples of non-co0mbustible materials. 
5)  Means of escape :  The building  should be provided with suitable means of cse there is fire in modern day multi-storeyed buildings. The occupants of the floor immediately above the the exit provisions should be such that the occupants of the floor immediately above and below that storey
6)  Corridor, width of staircase and location of staircase should   be suitably decided by keeping in view the safety requirements.
7)  The National Building Code had covered the topic of the fire protection in  detail  suitably decidd by keeping in view the safety  requirements.

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