unit 6 concepts of egress design 1. 2 means of egress and their design should be based on an...

Unit 6Unit 6

Concepts of Egress Concepts of Egress DesignDesign

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Concepts of Egress Concepts of Egress DesignDesign

Means of egress and their design Means of egress and their design should be based on an evaluation of a should be based on an evaluation of a buildingbuilding’’s total fire protection system s total fire protection system and an analysis of the population and an analysis of the population characteristics and hazards to the characteristics and hazards to the occupants of that building. occupants of that building.

The means of egress design should be The means of egress design should be treated as an integral part of the total treated as an integral part of the total system that provides reasonable life system that provides reasonable life safety from fire.safety from fire.

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FUNDAMENTALS OF FUNDAMENTALS OF DESIGNDESIGN

The approach to designing means of The approach to designing means of egress first requires a familiarity with egress first requires a familiarity with the reactions of people in fire the reactions of people in fire emergencies. emergencies.

These reactions can differ widely, These reactions can differ widely, depending on the physical and mental depending on the physical and mental capabilities and conditions of building capabilities and conditions of building occupants.occupants.

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FUNDAMENTALS OF FUNDAMENTALS OF DESIGNDESIGN

Patterns of movement of people, singly Patterns of movement of people, singly and in crowded conditions, must also be and in crowded conditions, must also be understood.understood.

In buildings used as schools or theaters In buildings used as schools or theaters housing highly mobile occupants, for housing highly mobile occupants, for example, there are certain reproducible example, there are certain reproducible flow characteristics from persons exiting flow characteristics from persons exiting the buildings. the buildings.

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Human Factors

The design and capacity of doors, passageways, stairways, and other components in the total means of egress are related to the of egress are related to the physical dimensions of the human body. physical dimensions of the human body.

The tendency of people to avoid bodily The tendency of people to avoid bodily contact with others should be contact with others should be recognized as a major factor in recognized as a major factor in determining the number of determining the number of persons who will occupy a given space at any given time.

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Human Factors

Given a choice, people usually a choice, people usually automatically establish automatically establish ““territoriesterritories”” to to avoid bodily contact with others.avoid bodily contact with others.

Crowding people into spaces where less than 3 ft of space per person is available under of space per person is available under nonemergency conditions may create a nonemergency conditions may create a hazard. hazard. ..

Human Factors

When the average area occupied per When the average area occupied per person is reduced to 2. ft. or less, person is reduced to 2. ft. or less, contact will be unavoidable.contact will be unavoidable.

Needless to say, under the Needless to say, under the psychological stresses imposed during psychological stresses imposed during a fire, such crowding and contact could a fire, such crowding and contact could contribute to crowd pressures, resulting contribute to crowd pressures, resulting in injuries.in injuries.

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Factors Affecting Movement of People

In level walkways an average walking speed of 250 ft/min is attained under free-flow conditions, with 25 ft2 of space available per person.

Speeds of less than 145 ft./min result in shuffling, and, finally, a jam point is reached with one person every 2 ft.2.


Further, flow can be 50 percent greater in short passageways less than 10 ft. long than through a long passageway of the same width...

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A 2 ft. projection resulting in a 33 A 2 ft. projection resulting in a 33 percent reduction in width reduces the percent reduction in width reduces the flow rate by approximately 10 percent. flow rate by approximately 10 percent. A major obstruction, though, such as A major obstruction, though, such as that which occurs at a ticket booth or that which occurs at a ticket booth or turnstile, may interrupt the movement turnstile, may interrupt the movement of people and reduce flow rates.of people and reduce flow rates.

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A 2 ft. projection resulting in a 33 A 2 ft. projection resulting in a 33 percent reduction in width reduces the percent reduction in width reduces the flow rate by approximately 10 percent. flow rate by approximately 10 percent.

A major obstruction, though, such as A major obstruction, though, such as that which occurs at a ticket booth or that which occurs at a ticket booth or turnstile, may interrupt the movement turnstile, may interrupt the movement of people and reduce flow rates.of people and reduce flow rates.

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Methods of Calculating Egress

Two major principles are used to determine the necessary egress width. They are based on width. They are based on anticipated population characteristics anticipated population characteristics identified with a specific occupancy.identified with a specific occupancy.

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The Flow Method

This method uses the theory of evacuating a building within a specified maximum building within a specified maximum period of time. Flow rates were period of time. Flow rates were traditionally set at 60 persons per 22 in. traditionally set at 60 persons per 22 in. width/ min through level passageways width/ min through level passageways and doorways.and doorways.

The flow method most commonly used commonly used today is based on so much width of an today is based on so much width of an egress element per person served.egress element per person served.

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The Capacity Method

This method is based on the theory that sufficient numbers of stairways should sufficient numbers of stairways should be provided in a building to adequately be provided in a building to adequately house all occupants of the building house all occupants of the building without requiring any movement, or without requiring any movement, or flow, out of the stairways.flow, out of the stairways.

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The Capacity Method

The capacity method recognizes that evacuation from high-rise buildings is physically very buildings is physically very demanding. Further, evacuation of a demanding. Further, evacuation of a health care facility is likely to be slow. health care facility is likely to be slow. Thus, design criteria are established to Thus, design criteria are established to permit holding occupants within exits or permit holding occupants within exits or areas of refuge.areas of refuge.

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Application

The capacity and flow methods may both be applied to efficient egress design, egress design, depending on specific circumstances. depending on specific circumstances.

Where people are expected to be Where people are expected to be physically or mentally sick, aged, physically or mentally sick, aged, asleep, or incapacitated in any way, asleep, or incapacitated in any way, evacuation and use of the flow method evacuation and use of the flow method can be augmented with the capacity can be augmented with the capacity method.method.

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Design of Means of Egress

Proper egress design permits everyone to everyone to leave the fire-endangered areas in the leave the fire-endangered areas in the shortest possible time with efficient exit shortest possible time with efficient exit use.use.

Maximum permitted evacuation travel distances are related to the occupant to the occupant characteristics, occupant alertness, and characteristics, occupant alertness, and building fire protection.building fire protection.

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Depending on the physical environment of the structure, the characteristics of the the characteristics of the occupants, and the fire detection and occupants, and the fire detection and alarm facilities, fire or smoke may prevent alarm facilities, fire or smoke may prevent the use of one means of egress. Therefore, the use of one means of egress. Therefore, at least one alternative means of egress at least one alternative means of egress remote from the first is essential.remote from the first is essential.

Provision of two separate means of egress is a of egress is a fundamental safeguard.fundamental safeguard.

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NFPA 101 limits openings in exit enclosures to those necessary for access to the enclosure from normally occupied spaces and for egress from the enclosure.

• Penetration of enclosures by ducts or other utilities constitutes a point of weakness and may result in contamination of the enclosure during a fire and should not be permitted.

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Provisions for handicapped persons is an important consideration in the design of an in the design of an emergency means of egress from a emergency means of egress from a building. building.

A 32 in. doorway is considered the A 32 in. doorway is considered the minimum width to accommodate a minimum width to accommodate a person in a wheelchair.person in a wheelchair.


It also must be noted that mobility handicaps are are not the only type of handicap needing not the only type of handicap needing to be addressed. Hearing and sight to be addressed. Hearing and sight impairments, along with certain mental impairments, along with certain mental disabilities, must be considereddisabilities, must be considered

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LIFE SAFETY CODE

In general, saving building occupants from a fire requires the following, all of which are identified in NFPA 101:

1. Sufficient number of properly designed, unobstructed means of egress of adequate capacity and arrangement.

2. Provision of alternative means of egress for use if one means of egress is blocked by fire, heat, or smoke.

LIFE SAFETY CODE

3. Protection of the means of egress Protection of the means of egress against fire, heat, and smoke during the against fire, heat, and smoke during the egress time determined by the egress time determined by the occupant load, travel distance, and occupant load, travel distance, and load, travel distance, and exit capacity.

4. Subdivision of areas by proper construction to provide areas of refuge in those occupancies where total evacuation is not a primary consideration.

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LIFE SAFETY CODE

5. Protection of vertical openings to limit the operation of fire protection equipment to a single floor.

6. Provision of detection or alarm systems to alert occupants and notify the fire department in case of fire.

7. Adequate illumination of the means of egress.

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LIFE SAFETY CODE

9. Protection of equipment or areas of unusual hazard that could produce a fire capable of endangering the egressing occupants.

10. Initiation, organization, and practice of effective drill procedures.

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LIFE SAFETY CODE

11. Provision of instructional materials and verbal alarm systems in high-density and high-life-hazard occupancies to facilitate adaptive behavior

12. Use of interior finish materials that prevent a high flame spread or dense smoke production spread or dense smoke production that could endanger egressing occupants. that could endanger egressing occupants.

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LIFE SAFETY CODE

NFPA 101 recognizes that full reliance cannot be placed on any single safeguard, because on any single safeguard, because any single protective feature may not any single protective feature may not function due to mechanical or human function due to mechanical or human failure. For this reason, redundant failure. For this reason, redundant safeguards, any one of which will result safeguards, any one of which will result in a reasonable level of life safety, in a reasonable level of life safety, should be provided.should be provided.

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LIFE SAFETY CODE

NFPA 101 examines the various occupancy populations according to their perceived according to their perceived life safety hazard, which includes life safety hazard, which includes psychological and sociological variables psychological and sociological variables in addition to the physiological and in addition to the physiological and environmental factors.environmental factors.

LIFE SAFETY CODE

These occupancy classifications are classifications are assembly, educational, day care, health assembly, educational, day care, health care, ambulatory health care, care, ambulatory health care, detention/correctional, residential, detention/correctional, residential, residential board and care, mercantile, residential board and care, mercantile, business, industrial, and storage.business, industrial, and storage.

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Influence of Building Constructionand Design

Fire-resistance rated design does not rated design does not ensure the life safety of the occupants ensure the life safety of the occupants of such buildings. of such buildings.

However, the ability of a structural However, the ability of a structural frame to maintain building rigidity frame to maintain building rigidity under fire exposure is important to the under fire exposure is important to the maintenance of the fire resistance maintenance of the fire resistance protection of exit enclosures.protection of exit enclosures.

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The protection of vertical openings is one of the most significant factors in the design of significant factors in the design of multistory buildings, from the multistory buildings, from the standpoint of life safety and exit design. standpoint of life safety and exit design.

Because of the natural tendency of fire Because of the natural tendency of fire to spread upward in a building, careful to spread upward in a building, careful attention to details of design and attention to details of design and construction are required to minimize construction are required to minimize this effect.this effect.

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The influence on the life safety of the occupants by the materials used in building construction depends materials used in building construction depends primarily on whether the materials will primarily on whether the materials will propagate flame, support combustion, or create propagate flame, support combustion, or create dense amounts of smoke when exposed to a dense amounts of smoke when exposed to a fire initially involving the building contents.fire initially involving the building contents.

Exit requirements are based on buildings of conventional design. Unusual buildings, such as those design. Unusual buildings, such as those without windows or those with inoperable without windows or those with inoperable windows, call for special consideration.windows, call for special consideration.

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Although it might be possible to break fixed windows windows to provide those same advantages, this poses to provide those same advantages, this poses several problems.several problems.

Automatic sprinklers are considered a primary requirement for life safety in windowless requirement for life safety in windowless buildings, buildings with inoperable windows, buildings, buildings with inoperable windows, and underground structures.and underground structures.

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Influence of Interior Finish,Furnishings, and Decorations

NFPA 101 limits the flame-spread index NFPA 101 limits the flame-spread index classification of interior finish materials on classification of interior finish materials on walls and ceilings to a maximum of 200, walls and ceilings to a maximum of 200, based on the results of tests conducted in based on the results of tests conducted in accordance with NFPA 255, Standard Method accordance with NFPA 255, Standard Method of Test of Surface Burning Characteristics of of Test of Surface Burning Characteristics of Building Materials.Building Materials.

In areas protected with automatic sprinklers, In areas protected with automatic sprinklers, the use of materials with higher flame-spread the use of materials with higher flame-spread index classifications sometimes is permitted.index classifications sometimes is permitted.

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Influence of Interior Finish,Furnishings, and Decorations

Furnishings and decorations—particularly Furnishings and decorations—particularly furnishings play an increasingly important role furnishings play an increasingly important role in loss of life by fire. in loss of life by fire.

Decorations can be treated with a flame Decorations can be treated with a flame retardant. Furnishings, on the other hand, are retardant. Furnishings, on the other hand, are difficult to control and regulate as a fire difficult to control and regulate as a fire hazard, since they are not attached to, or part hazard, since they are not attached to, or part of, the building construction or of the interior of, the building construction or of the interior finish materialsfinish materials

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Influence of Psychological Influence of Psychological andand

Physiological Factors on Physiological Factors on EgressEgress

The psychological and physiological conditions The psychological and physiological conditions of the occupants must be considered, in of the occupants must be considered, in addition to the physical configuration factors addition to the physical configuration factors of the building, in planning means of egress.of the building, in planning means of egress.

Because of the orientation of some people Because of the orientation of some people toward total evacuation and escape from the toward total evacuation and escape from the building, it is possible that they may attempt building, it is possible that they may attempt to evacuate a building in the conventional to evacuate a building in the conventional “down and out” approach despite instruction “down and out” approach despite instruction to the contrary.(911)to the contrary.(911)

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In two serious high-rise office building fires in In two serious high-rise office building fires in São Paulo, Brazil, the occupants moved São Paulo, Brazil, the occupants moved upward to the roof when their downward upward to the roof when their downward movement was inhibited by smoke and heat.movement was inhibited by smoke and heat.

In the MGM Grand Hotel fire in Las Vegas, In the MGM Grand Hotel fire in Las Vegas, Nevada, in November 1980, there also was Nevada, in November 1980, there also was upward movement in the stairways to the roof upward movement in the stairways to the roof and to rooms on upper floors when downward and to rooms on upper floors when downward travel was made untenable by smoke and travel was made untenable by smoke and heat.heat.

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Influence of Psychological andInfluence of Psychological andPhysiological Factors on EgressPhysiological Factors on Egress

It should be noted that rarely have successful It should be noted that rarely have successful helicopter rescues from the roof been helicopter rescues from the roof been performed. performed.

Roof-mounted structures, antennas, and Roof-mounted structures, antennas, and similar items make close approach difficult.similar items make close approach difficult.

In a significant fire, thermal updrafts make In a significant fire, thermal updrafts make approaching the building hazardous.approaching the building hazardous.

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All exits need to be conspicuously marked, All exits need to be conspicuously marked, because people are likely to be unfamiliar because people are likely to be unfamiliar with the various exits from an area under with the various exits from an area under fire conditions and thus neglect alternate fire conditions and thus neglect alternate means of egress.means of egress.

It is also important that the means of It is also important that the means of egress from a building be used as a matter egress from a building be used as a matter of daily routine, so the occupants will be of daily routine, so the occupants will be familiar with their location and operation.familiar with their location and operation.

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NFPA 101 requires that the main exit of NFPA 101 requires that the main exit of assembly occupancies, which also assembly occupancies, which also serves as the entrance, be sized to serves as the entrance, be sized to handle at least half of the total handle at least half of the total occupant load of the building. occupant load of the building.

Some assembly occupancies are now Some assembly occupancies are now required to have a main exit that can required to have a main exit that can accommodate two-thirds of the accommodate two-thirds of the occupant load. occupant load.



This is a result of the Station nightclub This is a result of the Station nightclub fire in West Warwick, Rhode Island, fire in West Warwick, Rhode Island, where 100 people died. where 100 people died.

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There are three critical parameters in There are three critical parameters in the effective use of the zoned the effective use of the zoned evacuation of personnel to areas of evacuation of personnel to areas of refuge within a building:refuge within a building:1. Proper construction to provide 1. Proper construction to provide compartmented areas that are protected compartmented areas that are protected from the effects of fire and smoke.from the effects of fire and smoke.



2. An effective verbal alarm system giving 2. An effective verbal alarm system giving clear and comprehensive instructions.clear and comprehensive instructions.

3. Effective evacuation drills to familiarize 3. Effective evacuation drills to familiarize the occupants with the way the system the occupants with the way the system functions. functions.

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Influence of Psychological andInfluence of Psychological andPhysiological Factors on EgressPhysiological Factors on Egress

It has been advocated that occupants in It has been advocated that occupants in fire-resistant, compartmented buildings fire-resistant, compartmented buildings used as hotels, motels, apartments, used as hotels, motels, apartments, dormitories, hospitals, and other health dormitories, hospitals, and other health care facilities should stay in their rooms care facilities should stay in their rooms rather than evacuate, because the rather than evacuate, because the rooms are the most adequate area of rooms are the most adequate area of refuge. This method has not been refuge. This method has not been adopted by NFPA 101 or by model adopted by NFPA 101 or by model building codes.building codes.

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Influence of Fire Protection Influence of Fire Protection EquipmentEquipment

It is unsuitable to rely totally on manual It is unsuitable to rely totally on manual or automatic fire extinguishing systems or automatic fire extinguishing systems in place of adequate means of egress, in place of adequate means of egress, because fire-extinguishing systems are because fire-extinguishing systems are subject to both human and subject to both human and

Under no condition can manual or Under no condition can manual or automatic fire suppression be accepted automatic fire suppression be accepted as a substitute for the provision and as a substitute for the provision and maintenance of proper means of egress.maintenance of proper means of egress.

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Influence of Fire Protection Influence of Fire Protection EquipmentEquipment

However, NFPA 101 does provide However, NFPA 101 does provide significant alternative methods of significant alternative methods of compliance for buildings protected by compliance for buildings protected by automatic sprinkler systems. automatic sprinkler systems.

In addition, automatic sprinkler systems In addition, automatic sprinkler systems and various automatic detection and various automatic detection systems are often installed in existing systems are often installed in existing buildings to compensate for problems buildings to compensate for problems with the means of egress.with the means of egress.

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DEFINITION OF THE TERMDEFINITION OF THE TERM“MEANS OF EGRESS“MEANS OF EGRESS””

A means of egress is a continuous path A means of egress is a continuous path of travel from any point in a building or of travel from any point in a building or structure to a public way that is in the structure to a public way that is in the open air outside at ground level.open air outside at ground level.

Egress consists of three separate and Egress consists of three separate and distinct parts:distinct parts:

1. Exit access. Portion of a means of egress 1. Exit access. Portion of a means of egress that leads to the entrance of an exit.that leads to the entrance of an exit.

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DEFINITION OF THE TERMDEFINITION OF THE TERM“MEANS OF EGRESS“MEANS OF EGRESS””

2. Exit. Portion of a means of egress that 2. Exit. Portion of a means of egress that is separated from the area of the building is separated from the area of the building from which escape is to be made by from which escape is to be made by walls, floors, doors, or other means that walls, floors, doors, or other means that provide the protected path necessary for provide the protected path necessary for the occupants to proceed with reasonable the occupants to proceed with reasonable safety to the exterior of the building.safety to the exterior of the building.

3. Exit discharge. Portion of a means of 3. Exit discharge. Portion of a means of egress between the termination of the egress between the termination of the exit and a public way.exit and a public way.

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CAPACITY OF MEANS OF CAPACITY OF MEANS OF EGRESSEGRESS

The capacity of exits is calculated using The capacity of exits is calculated using a capacity factor provided in NFPA 101. a capacity factor provided in NFPA 101. This capacity factor is given as This capacity factor is given as in./person and varies with the in./person and varies with the occupancy.occupancy.


The reason for these variations in exit The reason for these variations in exit capacity factors is to establish a capacity factors is to establish a consistent total evacuation time in consistent total evacuation time in different occupancies, based on the different occupancies, based on the physical ability, mental alertnesphysical ability, mental alertness, s, age, age, and sociological roles of the occupantsand sociological roles of the occupants

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Occupant LoadOccupant Load

Occupant load, or the number of people Occupant load, or the number of people to be expected in a building or an area to be expected in a building or an area within a building at any time for whom within a building at any time for whom exits must be provided, is determined exits must be provided, is determined by the actual anticipated occupant load.by the actual anticipated occupant load.

Occupant LoadOccupant Load

But not less than that number obtained But not less than that number obtained by dividing the gross area of the story by dividing the gross area of the story or the net area of a specific portion of or the net area of a specific portion of the building by the area in ft2 projected the building by the area in ft2 projected for each person. (or count seats)for each person. (or count seats)

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Doors should be side-hinged or pivoted Doors should be side-hinged or pivoted swinging type and should swing in the swinging type and should swing in the direction of egress travel, except in direction of egress travel, except in small rooms.small rooms.


In assembly occupancies, day-care In assembly occupancies, day-care centers, and schools, panic hardware centers, and schools, panic hardware should be installed on all egress doors should be installed on all egress doors equipped with latches that serve areas equipped with latches that serve areas with an occupant load of 100 or more.with an occupant load of 100 or more.

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Where doors protect exit facilities, as in Where doors protect exit facilities, as in stairway enclosures and horizontal stairway enclosures and horizontal exits, they normally must be kept exits, they normally must be kept closed to limit the spread of smoke. If closed to limit the spread of smoke. If open, they must be closed immediately open, they must be closed immediately in case of fire.in case of fire.


Although ordinary, fusible-link-operated Although ordinary, fusible-link-operated devices to close doors in case of fire are devices to close doors in case of fire are designed to close in time to stop the designed to close in time to stop the spread of fire, they do not operate soon spread of fire, they do not operate soon enough to stop the spread of smoke enough to stop the spread of smoke and are not permitted by NFPA 101.and are not permitted by NFPA 101.

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Sometimes, people keep self-closing Sometimes, people keep self-closing doors open with hooks or with wedges doors open with hooks or with wedges under the door. under the door.

Doors also can be blocked open to Doors also can be blocked open to provide ventilation, for the convenience provide ventilation, for the convenience of building maintenance personnel, or of building maintenance personnel, or to avoid the accident hazard of to avoid the accident hazard of swinging doors.swinging doors.


The following measures have been The following measures have been provided in the NFPA 101 to alleviate provided in the NFPA 101 to alleviate this undesirable situation:this undesirable situation:

1. Doors that are normally kept open 1. Doors that are normally kept open can be equipped with door closers and can be equipped with door closers and automatic hold-open devices that automatic hold-open devices that release the door and allow them to release the door and allow them to close when smoke detectors operateclose when smoke detectors operate..

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2. Doors that are normally closed can be 2. Doors that are normally closed can be equipped to open electrically or equipped to open electrically or pneumatically when a person approaches pneumatically when a person approaches the doorthe door

3. Doors that normally are closed can be 3. Doors that normally are closed can be opened and held open manually by opened and held open manually by monitors, as in schools.monitors, as in schools.

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Qualifications and limitations are Qualifications and limitations are applicable to each of these measures. applicable to each of these measures. One is that, in the event of electrical One is that, in the event of electrical failure, the door must close and remain failure, the door must close and remain closed unless it is opened manually for closed unless it is opened manually for egress purposes.egress purposes.

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Another major maintenance difficulty Another major maintenance difficulty with exit doors is the exterior door that with exit doors is the exterior door that is locked to prevent unauthorized is locked to prevent unauthorized access or for other reasons. NFPA 101 access or for other reasons. NFPA 101 specifies that when the building is specifies that when the building is occupied, all doors must be kept occupied, all doors must be kept unlocked in the direction of egress.unlocked in the direction of egress.

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NFPA 101 also provides “Access NFPA 101 also provides “Access Controlled Egress Doors.” The code Controlled Egress Doors.” The code spells out several limitations for these. spells out several limitations for these. One of the limitations included is that One of the limitations included is that when an occupant approaches the door when an occupant approaches the door from the egress side, a sensor must from the egress side, a sensor must unlock it.unlock it.


Locks on a door that let people exit but Locks on a door that let people exit but not enter are satisfactory, but even this not enter are satisfactory, but even this type of lock may not be satisfactory for type of lock may not be satisfactory for security purposes.security purposes.

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Possible measures to prevent Possible measures to prevent unauthorized use of exit doors include unauthorized use of exit doors include the following:the following:1. An automatic alarm that rings when the 1. An automatic alarm that rings when the door is openeddoor is opened

2. Visual supervision such as wired-glass 2. Visual supervision such as wired-glass panels, closed circuit television, and panels, closed circuit television, and mirrors,mirrors,

3. Automatic photographic devices to 3. Automatic photographic devices to provide pictures of usersprovide pictures of users

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So-called exit locks, with a break-glass So-called exit locks, with a break-glass unit actuated by striking a handle with unit actuated by striking a handle with the hand, are not permitted by NFPA the hand, are not permitted by NFPA 101 unless installed in conjunction with 101 unless installed in conjunction with panic bars.panic bars.


Other types of break-glass locks and Other types of break-glass locks and electrical controls for releasing exits electrical controls for releasing exits from a central point are not permitted from a central point are not permitted by NFPA 101. The exception is an by NFPA 101. The exception is an occupancy where controls may be occupancy where controls may be necessary, as in health care or necessary, as in health care or detention and correctional occupancies.detention and correctional occupancies.

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Panic HardwarePanic Hardware

Egress doors in assembly, day-care, and Egress doors in assembly, day-care, and educational occupancies, such as educational occupancies, such as schools or movie theaters, normally are schools or movie theaters, normally are equipped with panic hardware. equipped with panic hardware.

Basically, panic hardware devices are Basically, panic hardware devices are designed to facilitate the release of the designed to facilitate the release of the latching device on the door when a latching device on the door when a pressure not to exceed 15 lb.is applied pressure not to exceed 15 lb.is applied in the direction of exit travelin the direction of exit travel..

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Horizontal ExitsHorizontal Exits

A horizontal exit is a means of egress A horizontal exit is a means of egress from one building to an area of refuge from one building to an area of refuge in another building on approximately in another building on approximately the same level.the same level.

Or a means of egress through a 2 hour Or a means of egress through a 2 hour fire barrier to an area of refuge at fire barrier to an area of refuge at approximately the same level in the approximately the same level in the same building that affords safety from same building that affords safety from fire and smoke fire and smoke

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NFPA 101 recommends 3 ft2 of space NFPA 101 recommends 3 ft2 of space per person, with the exception of health per person, with the exception of health care or detention and correctional care or detention and correctional occupancies, where 6 to 30 ft2 of occupancies, where 6 to 30 ft2 of space is recommended.space is recommended.


Horizontal exits cannot comprise more Horizontal exits cannot comprise more than one-half the total required exit than one-half the total required exit capacity, except in health care facilities, capacity, except in health care facilities, where horizontal exits may comprise where horizontal exits may comprise two-thirds, and in detention and two-thirds, and in detention and correctional facilities, where horizontal correctional facilities, where horizontal exits can comprise 100 percent of the exits can comprise 100 percent of the total exit capacitytotal exit capacity

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StairsStairs

Exit stairs are arranged to minimize the Exit stairs are arranged to minimize the danger of falling, because one person danger of falling, because one person falling on a stairway may result in the falling on a stairway may result in the complete blockage of an exit.complete blockage of an exit.

Stairs must be wide enough for two Stairs must be wide enough for two persons to descend side by side, thus persons to descend side by side, thus maintaining a reasonable rate of maintaining a reasonable rate of evacuation, even though aged or evacuation, even though aged or mobility-impaired persons may slow the mobility-impaired persons may slow the travel on one side.travel on one side.

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StairsStairs

NFPA 101 specifies a minimum 11 in. NFPA 101 specifies a minimum 11 in. tread and a maximum 7 in. riser for new tread and a maximum 7 in. riser for new stairs. stairs.

Landings should be provided to break up Landings should be provided to break up any excessively long individual flight. any excessively long individual flight.

Continuous railings are now Continuous railings are now recommended for new stairs.recommended for new stairs.

New stairs more than 60 in. wide should New stairs more than 60 in. wide should have one or more center rails.have one or more center rails.

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StairsStairs

Stairs can serve as exit access, exit, or Stairs can serve as exit access, exit, or exit discharge. When used as an exit, exit discharge. When used as an exit, they must be in an enclosure that meets they must be in an enclosure that meets exit enclosure requirements or outside exit enclosure requirements or outside the building and properly protected.the building and properly protected.

Exit access stairs that connect two or Exit access stairs that connect two or more stories are vertical openings and more stories are vertical openings and must be protected as a vertical opening.must be protected as a vertical opening.

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StairsStairs

Doors on openings from each story are Doors on openings from each story are essential to prevent the stairway from essential to prevent the stairway from serving as a flue.serving as a flue.

In general, stairway enclosures should In general, stairway enclosures should include not only the stairs, but also the include not only the stairs, but also the path of travel from the bottom of the path of travel from the bottom of the stairs to the exit discharge, so that stairs to the exit discharge, so that occupants have a protected, enclosed occupants have a protected, enclosed passageway all the way out of the passageway all the way out of the buildingbuilding. .

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Smokeproof EnclosuresSmokeproof Enclosures

Smokeproof enclosures provide the Smokeproof enclosures provide the highest protected type of stair highest protected type of stair enclosure recommended by NFPA 101. enclosure recommended by NFPA 101.

Smokeproof EnclosuresSmokeproof Enclosures

Access to the stair is only by balconies Access to the stair is only by balconies open to the outside air, vented open to the outside air, vented vestibules, or mechanically pressurized vestibules, or mechanically pressurized vestibules, so that smoke, heat, and vestibules, so that smoke, heat, and flame will not spread readily into the flame will not spread readily into the tower even if the doors are accidentally tower even if the doors are accidentally left openleft open

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Exit PassagewaysExit Passageways

NFPA 101 specifies that an exit NFPA 101 specifies that an exit enclosure should not be used for any enclosure should not be used for any purpose that could interfere with its purpose that could interfere with its value as an exit and is strictly limited value as an exit and is strictly limited by the code. by the code.

Furthermore, penetration of the Furthermore, penetration of the enclosure by ducts and other utilities enclosure by ducts and other utilities may violate the protective enclosure.may violate the protective enclosure.

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Exit PassagewaysExit Passageways

The door openings in exit enclosures The door openings in exit enclosures should be limited to those necessary for should be limited to those necessary for access to the enclosure from normally access to the enclosure from normally occupied spaces. occupied spaces.

Therefore, doors and other openings to Therefore, doors and other openings to spaces such as boiler rooms, storage spaces such as boiler rooms, storage spaces, trash rooms, and maintenance spaces, trash rooms, and maintenance closets are not allowed into an exit closets are not allowed into an exit passageway.passageway.

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Fire Escape StairsFire Escape Stairs

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unit 6 concepts of egress design 1. 2 means of egress and their design should be based on an...

Documents

flow rates

means of egress design

movement of peoplea

crowding people

reactions of people

freeflow conditions

total means of egress

movement of peoplefurther