Means of emergency egress

“Although Fire Safety Rules and Standards are available in India, enforcement of these regulations, leaves much to be desired”. – R. R. Nair

1.0 INTRODUCTION

The word ‘egress’ has its origin from Latin ‘egressus‘gone out. It means the action of going out of or leaving a place.Emergency egress is a method of exit which people can access safely in an emergency. Emergency access and egress are critical during an emergency situation such as fire. During a fire, timing and quick response are essential to save lives and property. Unobstructed egress ensures that building occupants can exit a building to safety, Every building or structure, new or old, designed for human occupancy shall be provided with exits sufficient to permit the prompt escape of occupants in case of fire or other emergencies.

An applicable egress strategy is considered as one of the key fire safety aspects, especially in high rise buildings. As occupants increases, the time taken to evacuate the building will also increase. It may be remembered here that above certain heights, the vertical distance to be travelled by an occupant may subject them to additional risks. In such cases, the egress system may require re-evaluation in order to consider alternate strategies, such as relocation, refuge areas, role of elevators, etc.

In the aftermath of 11th, September 2001, new attention has being paid to many issues especially emergency egress from tall buildings.

Adequate means of escape for the occupants of a building in the event of a fire are a fundamental aspect of both legal obligations and good fire safety planning. If escape routes are not correctly designed and sited, there is a potential for major loss of life. Occupants will be endangered in any building where the escape routes are open to, or inadequately protected against, penetration by smoke and fire.

The adequacy of means of escape depends upon the layout and construction of the building as a whole, so the provisions of means of escape is a key part of the design process. The design of exits and other safeguards shall be such that reliance for safety to life in case of fire or other emergency will not depend solely on any single safeguards. Thus an ideal egress system will depend upon the building design, its intended use and its location and many other factors. In many cases, some form of engineering analysis, is to be conducted to determine the time required to evacuate the building, either fully or partially under a series of given
scenarios.

The primary objective for any fire related egress design is to provide appropriate facilities to allow occupants to move from the area of hazard to a place of relative safety, from which access to a place of ultimate safety can be achieved. The concept of areas of relative safety is an important one for tall building egress design, because escape to ultimate safety could take a considerable amount of time to achieve. The stairways, separate fire compartments, areas of refuge, etc. are all examples of places of relative safety. It may be reminded here that an ideal place of relative safety or ultimate safety is a location outside of the confines of the building at street level.

2.0 STATUTORY PROVISIONS

Many provisions for means of egress are prescribed in building laws and regulations in different countries. Most of these provisions are basically in the form of rescriptive standards or codes. For example, in Australia, the provisions for means of egress is as per the Building Code of Australia, 1988. In Canada, the provisions are as per the National Building Code of Canada, 2010. In Japan, it is as per the Building Standard Laws, 1990. In the United Kingdom, it is governed by the Building Regulations, 1991 and various British Standards. In the United States of America, there are manystandards relating to egress, issued by OSHA. Besides, there are many codes and standards, issued by NFPA, relating to fire safety and specific ones are NFPA 101: Life Safety Code, NFPA 101B: Code for Means of Egress for Buildings and Structures. The 2015 version of the International Building Code (IBC), and International Fire Code (IFC), issued by International Code Council, are acclaimed as important documents on the subject.

As far as India is concerned, the National Building Code (NBC), 2005, is the principle code dealing with the provisions of means of egress. Besides, many State Governments, notably Andhra Pradesh, Delhi, Gujarat, Haryana, Himachal Pradesh, Karnataka, Kerala, Maharashtra, Orissa, Tamil Nadu, Uttar Pradesh and West Bengal have made fire safety regulations and most of the provisions in these rules are based on the National Building Code. Various Local Bodies in India, have also brought out Development Control Regulations (DCR) which also follow the provisions of the National Building Code, 2005.

Due to the limitations of space no attempt has been made in this article to make a comparison of the provisions available in various countries with regard to means of egress. However, this article will focus on various provisions available in the National Building Code, 2005; Fire Safety Regulations brought out by various states and Development Control Regulations brought by various Local Bodies in particular, Ahmedabad, Bangalore, Delhi, Mumbai and Navi Mumbai.

3.0 MEANS OF EGRESS

A means of egress is a continuous and unobstructed way of exit travel from any point in a building or structure to a public way and consist of three separate and distinct parts: the way of exit access, the exit, and the way of exit discharge. In other words, emergency egress is a continuous and unobstructed way of travel from any point in a building or structure to a place of comparative safety. A means of egress may include horizontal and vertical travel routes including intervening rooms, spaces, doorways, hallways, corridors, passage-ways, balconies, ramps, stairs, enclosures, lobbies, escalators, courts and yards.

3.1 Components of Egress

A means of egress components consists of three separate and distinct parts, viz.: (i) The Exit Access; (ii) The Exit and; (iii) The Exit Discharge.

3.1.1 The Exit Access:

The Exit Access is “that portion of the means of egress system that leads from an occupied portion of a building or structure to an exit”. It includes halls, corridors, aisles, and other walking or escape paths.

3.1.2 The Exit:

Exit is a passage, channel or means of egress form any building, storey or floor area to a street or other open space of safety. It includes exterior exit doors at ground level, exit enclosures, exit passageways, exterior exit stairs, exterior exit ramps, vertical exits, horizontal exits and outside exits.

• Vertical Exit: A vertical exit is a means of exit used for ascending or descending, between two or more levels, including stairways, smoke proof towers, ramps and fire escapes.
• Horizontal Exit: A horizontal exit is an arrangement which allows alternative egress from a floor area at or near the same level in an adjoining building or an adjoining part of the same building with adequate fire separation. The width of horizontal exit shall be same as for the exit doorways.
• Outside Exit: An outside exit is an exit from the building to a public way, to an open area leading to a public way or to an enclosed fire resistant passage leading to a public way.

3.1.3 The Exit Discharge:

The exit discharge is “that portion of a means of egress system between the termination of an exit and a public way which is a street, alley, or other paths dedicated for public use”. Normally a door to the outside or into a protected corridor leading to the outside.

4.0 NUMBER OF EXITS

The number and size of various exits shall be provided in the building is decided on the occupants in each room and floor, based on the Occupant Load, Occupant per Unit Exit Width, Travel Distance and Height Of the Buildings as per provisions of building bye-laws. For Occupant Load, Occupant per Unit Exit Width and Travel Distance reference may be made to 4.3, 4.4 and 4.5 of Part 4 NBC, 2005.

4.1 Occupant Load

As per Table 20 of Part 4, NBC, 2005, the Occupant Load for Residential, Educational, Institutional, Mercantile (Upper sale floors), Business & industrial, Storage and Hazardous are 12.5, 4, 15, 6, 10, 30 and 10 respectively.

4.2 Occupant per Unit Exit Width

As per Table 21, Part 4 of NBC, 2005, the Occupants Per Unit Exit Widthfor Residential, Educational, Institutional and Hazardous is 25; for Assembly is 40 and for Business, Mercantile, industrial and Storage is 50.

4.3 Travel Distance

Travel distance is an important parameter in deciding egress strategy. The total occupants from a particular floor must evacuate: 1 ½ minutes for Type 2 construction and 1 minute for Type 3 construction. The size of the exit door/exit way shall be calculated accordingly keeping in view the travel distance as per Table 22, Part 4, of NBC, 2005. It may also be noted that the Exits shall be so located as per the travel distance given in Table 22 of NBC, 2005. According to Clause 4.5.2 of Part 4 of NBC, 2005, the travel distance to an exit from the dead end of a corridor shall not exceed half the distance specified in Table 22, Part 4, of NBC, 2005, except in assembly and institutions occupancies in which case it shall not exceed 6 meters. Further it may be noted here that fully sprinkled building, the travel distance may be increased by 50% of the value specified.

As per Table 22, Part 4 of NBC, 2005, the Maximum Travel Distance for Type 1 & 2 construction for Residential, Educational, Institutional, Assembly, Business, Mercantile and Storage is 30 meters; for Industrial is 45 meters and for Hazardous is 22.5 meters. Similarly the Maximum Travel Distance for Type 3 & 4 construction for Residential, Educational and Institutional is 22.5 meters; for Assembly, Business & Mercantile is 30 meters.

Travel distance limitations are usually taken into consideration for entry into the buildings protected egress system – typically the stairways. It may be noted that even if the vertical egress components are efficiently designed and people descend relatively unhindered within the stairways the time taken to reach ground level will increase due the onset of fatigue for evacuating occupants of varying fitness levels. Thus a time-based approach to egress may be more appropriate than a traditional distance-based approach. Thus time parameter, may form an integral element of egress goals or objectives.

5.0 GENERAL EXIT REQUIREMENTS:

An exit may be a doorway, corridor; passageway(s) to an internal staircase, or external staircase, or to a verandah or terrace(s), which have access to the street, or to the roof of a building or a refuge area. An exit may also include a horizontal exit leading to an adjoining building at the same level. Lifts and escalators shall not normally be considered as exits. Every exit, exit access or exit discharge shall be continuously maintained free of all obstructions or impediments for full use in the case of fire or other emergency. Every building meant for human occupancy shall be provided with exits sufficient to permit safe escape of occupants, in case of fire or other emergency. In every building or structure, exits shall comply with the minimum requirements of this part, except those not accessible for general public use. No building shall be so altered as to reduce the number, width or protection of exits to less than that required. Exits shall be clearly visible and the route to reach the exits shall be clearly marked and signs posted to guide the occupants of the floor concerned. Signs shall be illuminated and wired to an independent electrical circuit on an alternative source of supply. The sizes and colours of the exit signs shall be in accordance with IS-9457:1980, IS-12407:1988 & IS-12349:1988.

The colour of the exit signs shall be green. However, this provision shall not apply to residential occupancies less than 15 mts in height. The floors of areas covered for the means of exits shall be illuminated to values not less than One foot candle (10 lux) at floor level. In auditoriums, theatres, concert halls and such other places of assembly, the illumination of floor exit /access may be reduced during period of performance to value not less than 1/5 foot candle (2 lux). Fire doors with 2 hour fire resistance shall be provided at appropriate places along the escape route and particularly at the entrance to lift lobby and stairwell where a funnel or flue effect may be created, inducing an upward spread of fire to prevent spread of fire and smoke. All exits shall provide continuous means of egress to the exterior of a building or to an exterior open space leading to a street. Exits shall be so arranged that they may be reached without passing through another occupied unit.

6.0 ESCAPE STAIRCASES

All buildings, having area more than 500 sq. meters on each floor shall have a minimum of two staircases. They shall be of enclosed type; at least one of them shall be on external walls of buildings and shall open directly to the exterior, interior open space or to an open place of safety. Further, the provision of alternative staircases shall be subject to the requirements of travel distance being complied with.

6.1 Doorways

Every exit doorway shall open into an enclosed stairway or a horizontal exit of a corridor or passageway providing continuous and protected means of egress. No exit doorway shall be less than 1000 mm in width except assembly buildings where door width shall be not less than 2000 mm. Exit doorways shall be not less than 2000 mm in height. It shall open outwards, that is, away from the room, but shall not obstruct the travel along any exit. No door, when opened, shall reduce the required width of stairway of landing to less than 900 mm. Overhead or sliding doors shall not be installed. However, in the case of buildings where there is a central corridor, the doors of rooms shall open inwards to permit smooth flow of traffic in the corridor.Exit door shall not open immediately upon a flight of stairs. A landing equal to at least the width of the door shall be provided in the stairway at each doorway. The level of landing shall be the same as that of the floor, which it serves. Exit doorways shall be
openable from the side, which they serve without the use of a key. Mirrors shall not be placed in exit doors to avoid confusion regarding the direction of exit.

6.3 Corridors & Passageways

Exit corridors and passageways shall be of width not less than the aggregate required width of exit doorways leading from them in the direction of travel to the exterior. Where stairways discharge through corridors and passageways, the height of corridors and passageways shall be not less than 2.4 m. All means of exit including staircases, lifts, lobbies and corridors shall be adequately ventilated.

6.4 Internal Staircases

As per the NBC, 2005, the internal wall of staircase shall be of brick or reinforced concrete with a minimum of Two hours fire rating. Access to main staircase shall be through a fire /smoke check door of a minimum 2-hour fire resistance rating. Fire resistance rating may be reduced to One hour for residential buildings (other than hotels and starred hotels).

No gas piping, electrical panels or AC ducts shall be allowed in the stairway. However service shafts/ducts may be permitted. Electrical shafts/ducts shall have not less than Two hours fire resistance. For other services shafts/ducts, the fire resistance shall be not less than One hour. Notwithstanding the detailed provision for exits, the minimum width for staircases shall be provided as: Residential buildings (1.0 m); Residential hotel buildings (1.5 m); Assembly buildings like auditorium, theatres and cinemas (2.0 m); Educational buildings up to 30 m in height (1.5 m); Institutional buildings like hospitals (2.0 m); all other buildings (1.5 m). The minimum width of tread without nosing shall be 250 mm for internal staircase of residential buildings. However, this shall be 300 mm for assembly, hotels, educational, institutional, business and other buildings. The treads shall be constructed and maintained in a manner to prevent slipping. The maximum height of riser shall be 190 mm for residential buildings and 150 mm for other buildings and the number shall be limited to 15 per flight. Handrails shall be provided at a height of 1000 mm to be measured from the base of the middle of the treads to the top of the handrails. Balusters/Railing shall be provided in such a way that the width of staircase does not reduce. The maximum gap between balusters shall be 150 mm.

The number of people in between floor landings in staircase shall not be less than the population on each floor for the purpose of design of staircase. The design of staircase shall also take into account the following:

1. The minimum headroom in a passage under the landing of a staircase and the staircase shall be 2.2 m.
2. No living space, store or other fire risk shall open directly into the staircase or staircases.
3. External exit door of staircase enclosure at ground level shall open directly to the open spaces or through a draught lobby, if necessary.
4. The main and external staircases shall be continuous from ground floor to the terrace level.
5. Lifts shall not open in staircase.
6. No combustible material shall be used for decoration/wall paneling in the staircase.
7. Beams/Columns and other building features shall not reduce the head room/ width of the staircase.
8. The exit sign with arrow indicating the way to the escape route shall be provided at a suitable height from the floor level on the wall and shall be illuminated by electric light connected to corridor circuits. All exit way marking signs should be flush with the wall and so designed that no mechanical damage shall occur to them due to moving of furniture or other heavy equipment. Further, all landings of floor shall have floor indicating boards prominently indicating the number of floor as per byelaws. The floor indication board shall be placed on the wall immediately facing the flight of stairs and nearest to the landing. It shall be of size not less than 0.5 m x 0.5 m.
9. Individual floors shall be prominently indicated on the wall facing the staircases.
10. In case of single staircase, it shall terminate at the ground floor level and the access to the basement shall be by a separate staircase. The second staircase may lead to basement levels provided the same is separated at ground level by a ventilated lobby with discharge points to two different ends through enclosures.

6.5 External Staircases

An external staircase is desirable to be provided for high rise buildings. External stairs, when provided shall comply with the following:

1. External stairs shall always be kept in sound operable conditions.
2. All external stairs shall be directly connected to the ground.
3. Entrance to the external stairs shall be separate and remote from the internal staircase.
4. Care shall be taken to ensure that no wall opening or window opens on to or close to an external stairs.
5. The route to the external stairs shall be free of obstructions at all time.
6. The external stairs shall be constructed of non-combustible materials, and any doorway leading to it shall have the required fire resistance
7. No external staircase, used as a fire escape, shall be inclined at an angle greater than 45O from the horizontal.
8. External stairs shall have straight flight not less than 1250 mm wide with 250 mm treads and risers not more than 190mm. The number of risers shall be limited to 15 per flight.
9. Handrails shall be of height not less than 1000mm and not exceeding 1200 mm. There shall be provisions of balusters with maximum gap of 150 mm.
10. The use of spiral staircase shall be limited to low occupant load and to a building not exceeding 9 m in height. A spiral stair case shall be of not less than 1500 mm in diameter and shall be designed to give adequate head room.
11. Unprotected steel frame staircase shall not be accepted as means of escape. However, Steel Staircases in an enclosed fire rated compartment of Two hours can be accepted as means of escape.

In high-rise buildings, an additional staircase is recommended, as an emergency escape route. As per NBC, Clause 4.6.2, Part – 4 for all buildings above 15 meters, in heights should be provided with a second staircase. The width of the Fire Escape Staircase should not be less than 1.25 meters.

In high-rise building having twin towers a sky bridge connecting the towers can be used as an additional emergency escape route. For example the Petronas Twin Towers in Kuala Lumpur, the sky bridge is used for the horizontal transfer of occupants between the towers during a fire emergency (See Fig 01).

The internal view of the sky bridge of the Petronas Twin Towers which is used as an egress route between two towers (See Fig 02).

7.0 FIRE DOORS

A fire door is a door with a fire-resistance rating used as part of a passive fire protection system to reduce the spread of fire or smoke between compartments and to enable safe egress from a building or structure. In other words a Fire Door serves as a barrier to limit the spread of fire and restrict the movement of smoke (See Fig 03).

Doors equipped with internal windows must remain intact under fire conditions and hose stream impact resistance. Both the door leaf (the swinging panel of the door) and the door frame are required to meet the guidelines of the testing agency. The door frame includes the fire or smoke seals, door hardware, and the structure that holds the fire door assembly in place. Fire doors are sometimes rendered unable to provide its listed fire resistance. Sometimes fire doors have very large gaps at the foot of them, an inch or two even, allowing air movement. This can lead the occupants of a building to question their status as ‘real’ fire doors. Most fire doors are designed to be kept closed at all times. Some doors are designed to stay open under normal circumstances, and close automatically in the event of a fire. Whichever method is used, the door’s movement should never be impaired by a doorstop or other obstacle (See Fig 04)

It is also very important that where a fire door is installed, any gaps left in the opening between the wall and the door frame must be properly filled with fire resisting material. There are 20, 30, 45, 60 and 90-minute-rated fire doors that are certified by an approved laboratory. As per 4.8.4.1 of NFPA, testing of fire doors include a maximum door undercut of ¾ inch. As per D.5 of NFPA, corridors have a fire rating of 1 hour or less, and the fire doors in them are to have a fire rating of 20 min or 30 min, the intent of which is mainly to restrict smoke travel. As per 5.2.4 of NFPA requires annual inspections of fire-resistance rated door and frame assemblies. As per the NBC, 2005, Clause 4.2.9, Part 4, fire doors with a two hours fire resistance shall be provided at appropriate places along the escape route and particularly at the entrance of lift lobby and stair well, where a funnel or flue effect may be created inducing an upward spread of fire to prevent spread of fire and smoke.

8.0 FIRE LIFTS

As per the “NBC, 2005” (Clause 4.15), one lift in the building shall be designed and designated as fire lift. The fire lift shall meet the requirements specified in Annex C of Part 4, NBC, 2005, which reads as:

1. To enable fire services personnel to reach the upper floors with the minimum delay, one fire lift per 1200 sq. meters of floor area shall be provided and shall be available for the exclusive use of the firemen in an emergency.
2. The lift shall have a floor area of not less than 1.4 m2. It shall have loading capacity of not less than 545 KG (8 persons lift) with automatic closing doors of minimum 0.8 m width.
3. The electric supply shall be on a separate service from electric supply mains in a building and the cables run in a route safe from fire, that is, within the lift shaft. Lights and fans in the elevators having wooden paneling or sheet steel construction shall be operated on 24 volt supply.
4. Firefighting lift should be provided with a ceiling hatch for use in case of emergency, so that when the car gets stuck up, it shall be easily openable.
5. In case of failure of normal electric supply, it shall automatically change over to alternate supply. For apartment houses, this changeover of supply could be done through manually operated changeover switch. Alternatively, the lift shall be so wired that in case of power failure, it comes down at the ground level and comes to stand-still with door open.
6. The operation of fire lift should be by a simple toggle or two–button switch situated in glass-fronted box adjacent to the lift at the entrance level. When the switch is on, landing call points will become inoperative and the lift will be on car control only or on a priority control device. When the switch is off, the lift will return to normal working, when this lift can be used by the occupants in normal times.
7. The words ‘Fire Lift’ shall be conspicuously displayed in fluorescent paint on the lift landing doors at each floor level.
8. The speed of the fire lift shall be such that it can reach the top floor from ground level within one minute.

Firefighting lifts are becoming more and more popular for evacuation purposes. This method is particularly useful in super high-rise buildings, where the large vertical travel distances result in a number of significant problems like possible increase of exposure to smoke and fire, increased fatigue during evacuation and difficulty in safe evacuation of injured, infants, aged or disabled occupants. This new method has been incorporated in the design of many tall building in the world, for example Petronas Twin Towers in Kuala Lumpur, Malaysia and Burj Khalifa in Dubai, UAE.

9.0 REFUGE AREAS

A refuge area serves as an important means to rescue the occupants in the event of a fire in the building. As per Clause 4.12.3 of Part 4 and Annex – C – 1 – 11 of NBC, 2005, following provisions shall apply to all high rise buildings except multi-family dwellings where refuge area of not less than 15 sq. meters shall be provided on the external walls. In case of buildings having more than 24 meters in height, refuge area of 15 sq. meters or an area equivalent to 0.3 sq. meters per person to accommodate the occupants of two consecutive floors, whichever is higher, shall be provided as under: (i) For floors above 24 meters and upto 39 meters – One refuge area on the floor immediately above 24 meters. ii) For floors above 39 meters – One refuge area on the floor immediately above 39 meters and so on after every15 meters. The refuge area shall be provided on the periphery of the floor, preferably on a cantilever projection, open to air at least on one side, protected with suitable railings (See Fig 05).

The refuge area shall not be allowed to be used for any other purpose and it shall be the responsibility of the owner / occupier to maintain the same clean and free of encumbrances and encroachment to all times. Lifts and / or open type staircases shall not open into refuge area.However, residential flats in multistoried buildings with balcony, need not be provided with refuge area, however flats without balcony shall be provided with refuge area as given above.

10.0 EMERGENCY ESCAPE LIGHTING

As per Clause 4.16 of Part 4, NBC, 2005, emergency lighting shall be powered from a source independent of that supplying the normal lighting. Emergency lighting units shall conform to IS: 9583-1981. Escape lighting shall be capable of: (i) Indicating clearly and unambiguously the escape routes. (ii) Providing adequate illumination along such routes to allow safe movement of persons towards and through the exits. (iii) Ensuring that fire alarm call points and firefighting equipment provided along the escape routes can be readily located.

The horizontal luminance at floor level on the centerline of an escape route shall be not less than 10 lux. In addition, for escape routes up to 2m wide, 50% of the route width shall be lit to a minimum of 5 lux. The emergency lighting shall be provided to be put on within one second of the failure of the normal lighting supply. Escape lighting luminaries should be sited to cover the locations such as corridors, exit door, escape route, staircase, change of floor level, final exit, fire alarm call point,firefighting equipment, safety signs, etc. Emergency lighting systems shall be designed to ensure that a fault or failure in any one luminaire does not further reduce the effectiveness of the system.

The luminaires shall be mounted as low as possible, but at least 2 m above the floor level. Signs are required at all exits, emergency exits and escape routes, which should comply with the graphic requirements of the relevant Indian standards. Emergency lighting luminaires and their fitting shall be of non-flammable type. It is essential that the wiring and installation of the emergency lighting systems are of high quality so as to ensure their perfect serviceability at all times. The emergency lighting system shall be capable of continuous operation for a minimum duration of 1 hour and 30 minutes even for smallest premises. The emergency lighting system shall be well maintained by periodical inspections and tests so as to ensure their perfect serviceability at all times.

10.1 Illumination of Means of Exit.

Emergency lights shall be provided to the staircases and corridors. As per Clause 4.17 of Part 4, NBC, 2005, Staircase and corridor lights shall conform to the following: (a) The staircase and corridor lighting shall be on separate circuits and shall be independently connected so that they could be operated by one switch installation on the ground floor easily accessible to firefighting staff at any time irrespective of the position of the individual control of the light points, if any. It should be miniature circuit breaker type of switch so as to avoid replacement of fuse in case of crisis; (b) Staircase and corridor lighting shall also be connected to alternative supply.

The alternative source of supply may be provided by battery continuously trickle charged from the electric mains; and (c) Suitable arrangements shall be made by installing double throw switches to ensure that the lighting installed in the staircase and the corridor does not get connected to two sources of supply continuously. Double throw switch shall be installed in the service room for terminating the stand-by supply. The means of exit paths can be illuminated using Photo luminescent Egress Path Marking (See Fig 06).

11.0 OBSTRUCTION OF ESCAPE ROUTES

As per Clause 4.2.3, Part 4 of NBC 2005, every exit, exit access or exit discharge shall be continuously maintained free of all obstructions or impediments to full use in the case of fire or other emergency. The very purpose of keeping a provision for clean lobby is that during an emergency or in the event of a fire, the occupants should get out of the building without any obstruction. However, this rule is not being observed by many occupants especially those who occupy multistory buildings and high buildings.(See Fig 07, 08, 09 and10)

12.0 CONCLUSION

Ensuring Life Safety is the most essential aspect of all Building Codes. High rise and multi storey buildings pose many challenges in particular the large number of occupants and large vertical travel distance. Traditionally the means of escape strategy by and large is based on the principle of single stage evacuation. To achieve this, buildings are designed with stairways of sufficient width to enable all the occupants to evacuate simultaneously.

In high-rise building with large number of occupants, it has been found that single phase evacuation is a time consuming process and is impracticable. Thus the best method adopted today all over the world for evacuation in high-rise building is phased evacuation in which the building is evacuated in different phases in the event of fire. This system of evacuation has been incorporated in the buildings codes brought out by many countries and also NFPA 72.Probably an emergency lift control procedure is required to be developed for adoption in case of fire emergency.

As the height of the buildings are increasing day by day, conventional methods of evacuation have become more difficult. A new set of escape systems are now available for fast evacuation during an emergency. The new systems include, Rescue Chutes, Suspended Rescue Platforms (See Fig 11), Controlled Decent Devices, Non-Structural Depended Devices, etc.

Similarly, injured, infants, aged or disabled occupants can be now safely evacuated using special devices such as Wheelchair stair climbers (See Fig 12), Evacuation Chairs, etc.

After the introduction of the NBC, 2005, by and large, most of the State and Local Bodies have adopted many of the code provisions in their own Building Regulations. Delhi, Mumbai and Gujarat Regulations on the Life Safety and Fire Protection requirements of buildings are mostly based on NBC Part 4.

Although Fire Safety Rules and Standards are available in India, enforcement of these regulations, leaves much to be desired. Due to the vested interests and political pressures, implementation of some of the provisions in the regulations is rendered difficult, and code violations are frequent.Fortunately, the Judiciary in many States has been intervening in several cases of building codes violations in particular in cases involving, violations of Fire Safety Rules.

13.0 REFERENCES

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33. Nair, R. R.- Fire Safety In India – An overview, Industrial Safety Review, October 2013.
34. Nair, R. R.- Fire Safety Management, Industrial Safety Review, January 2014.
35. Nair, R. R.- Safety in High Rise Buildings, Industrial Safety Review, November 2011.
36. National Building Code of Canada, 2010, National Research Council, Ontario, Canada, 2010.
37. Occupational Safety and Health Administration (OSHA), USA, Means of Egress, OSHA Regulations, Part 1910 Subpart E.
38. The Building Regulations 1991 – Approved Document B, HMSO, 1991.
39. USA, National Fire Protection Association (NFPA): NFPA 72, NFPA 101 and NFPA 101B.
40. USFA and FEMA, courtesy for A typical Fire Double Door.

Mr. R. R. Nair has more than 50 years’ experience in Occupational Safety, Health & Fire Protection. He has carried out about 80 projects in SHE Pan India (Safety Audits, Accident Investigations, Environmental Studies, Hazard Identification and Risk Assessment (HIRA), Hazardous Zone Classifications, Fire Safety Audits in High Rise Buildings, etc.). He is author of 15 books and about 75 articles in various topics on SHE.
He can be contacted on:
M: +91 7045172050, Resi: +91 477 2266994
E-mail: ceo@shib.co.in / shib@vsnl.com
Website: www.shib.co.inp