5 fire safety principles

FIRE SAFETY FIRE SAFETY PRINCIPLESPRINCIPLES

4.04.0

The Fire Triangle:

Three elements - fuel, oxygen and heat - are required to start a fire.

The oxidation process will not be possible without any one of these elements.

Fuel (Fire Load)

Oxygen (Ventilation) Heat (Ignition)

Fire is a rapid oxidation process accompanied by the evolution of heat, light, flame and the emission of sound.

Definition and Causes of Fire2Intro

Ordinary combustible materials such as wood, cloth, paper, rubber and plastics, etc.

Class A:

Flammable or combustible liquids, flammable gases.

Class B:

Energized electrical equipment

Class C:

Fire involving:

Combustible metals such as potassium, sodium, magnesium and other reactive metals

Class D:

How to Suppress:

Use Water

Exclude air from burning materials

No Water; Use electrically non-conductive extinguishing agents such as gaseous systemsHeat-absorbing medium which is not reactive with burning metals

Intro Classes of Fire3

IntroFire Growth

2

Pre-flashover or growth phase

Stage 1:

FlashoverStage 2:

Fully developed fire (Stable phase)

Stage 3:

Decay (Cooling Period)

Stage 4:

Involves flaming combustion of an item and may lead to a spread of fire; or a smoldering, poorly-ventilated fire with substantial smoke.

Rapid change from a local fire to one involving all combustible materials in a room.

All materials in compartment are alight; maximum rate of heat release is dependent on either available ventilation or quantity of fuel.

Gradual consumption of fuel in the compartment.

Stages

Stage 1

Stage 2

Stage 3

Stage 4

Active Fire ProtectionDetection, activation and suppression

Passive Fire ProtectionResistance to heat and flames of fire rated constructions

Temperature Time

Slow rate of burning

Development of heat and flames

Load bearing capacity of materials is maintained. Prevention of fire spread to other

compartments.

This graph shows where active and passive fire protection will play an important part during the development of fire.

IntroFire Growth

2

Architectural Intervention during Fire Growth

Behavior of Fire and Smoke1

Vertical Shaft or Duct(Stack Effect) Suspended Ceiling

Ceiling Void

Smoke and Flame likely to re-enter Enclosed Area

Vertical Shaft or Duct

Outlet to adjoining space

Enclosed Area

Outlet to open air

1.00 m

Intro

Internal Fire Spread due to:

Internal Fire Spread between Rooms and Floors

ThroughVerticalShafts

Through Air Ducts

Through Ceiling and Collapsed Partitions

Through Non-Fire Rated Doors

Origin of Fire

Fire Spread2Intro

Fire Spread

Congested High Fire Load Areas

External Fire Spread due to:

Intro

Fire Spread

External Fire Spread due to:

Intro

Loss of Integrity of Fire Wall

Fire Spread2

Ignition of Materials



Ignition of MaterialsConvection Currents

Origin of Fire

Proximity of Buildings

IntroExternal Fire Spread due to:

Aims inFire Safety Design

A To prevent fire

B To safeguard the lives of occupants and

firefighters

C To reduce damage on the building, its contents,

and on surrounding buildings

Basic Principles

1Fire Avoidance

2 Fire Detection

3 Fire Growth Restriction

4Fire Containment

5 Fire Control

6Smoke Control

7 Escape Provisions

Definition & Implication

PrinciplesFire Avoidance11Reducing the possibility of accidental ignition of construction materials, as well as fittings and fixtures.

This implies:

a. keeping separate heat sources and materials which might ignite readily through proper planning and zoning

b. need to specify materials to reduce the risk of fire starting

c. reducing fire load

Basic

PrinciplesFire Avoidance11

For H

ospi

tals

(eg. Hospitals)Fire Zoning

Basic

For M

ost B

uild

ings

1. Life Risk Areas – areas in which all occupants are ambulant and able to move unaided away from a fire

- eg. Outpatient department; Service Zone

2. High Fire Risk Areas – areas which, due to their function, are more usually susceptible to an outbreak of fire, or to a rapid spread of fire or smoke.

- eg. Kitchen or Boiler Room

3. High Fire Load Areas – areas which, because of their construction or contents, contain large amounts of combustible materials, thereby constituting a fire load in excess of that normally found

- eg. Gas Storage, Linen Closets

4. High Life Risk Areas – areas in which persons may reside and are not able to move unaided away from a fire.

- eg. Intensive Care Unit, Operating Department

LEGEND:

HIGH LIFE RISK

HIGH FIRE LOAD

HIGH FIRE RISK

BasicPrinciples(eg. Hospitals)Fire Zoning

Fire Avoidance1LIFE RISK

Choice of Materials and Knowledge on Material Performance

1

Steel- does not burn

- may buckle in fire- high conductivity

spreads heat- loses half its strength

in 550°C

Timber- combustible- little loss of

strength as charcoal formed insulates

wood core- spreads flames

Masonry- high fire resistance- cracks at 575°C- are subject to high temperatures during manufacture

Calcium Silicate- excellent thermal shock resistance- up to 1000°C- suitable for cladding structural members

Glass- standard float, toughened and laminated glass panes do not provide any fire resistance- monolithic fire-rated glass is available

BasicPrinciplesFire Avoidance21

Concrete-high fire resistance

- disintegrates at 400-500°C

- holes in concrete will expose steel structural

members

“the amount of material which is able to burn and release heat and smoke”

In a compartment, limiting fuel will help reduce the dangers of heat and smoke.

Building contents make up the majority of the fire load, since most fires start from the ignition of these contents.

The total amount of fuel in a building, its accessibility to fire engines, the availability of water, etc. will determine the level of fire resistance and the maximum size of a building compartment.

BasicPrinciplesFire Avoidance21Knowledge on Fire Load

1

Visual Fire DetectionTo visually expose FIRE RISK and FIRE LOAD areas to building occupants.

BasicPrinciples

Patient Room

Nurse Station

Patient Room

Sto

2Fire Detection

Lounge

fire-prone areas should be visually

accessible

provide peepholes on doors

BasicPrinciplesVisual Fire Detection

2Fire Detection

Makes use of manual and automatic (electric/ electronic) methods of informing the occupants in charge that a fire has occurred in a given location.

Heat and smoke alarm systems inside Fire Risk and Fire Load

areas.

BasicPrinciplesMechanical Fire Detection

2Fire Detection

Fire alarm systems must be accessible in all zones especially in

fire-prone areas.

Aimed at ensuring that the growing fire is extinguished immediately and at providing adequate time for firemen to arrive, control the fire and evacuate the occupants.

BasicPrinciples

Actively extinguishing or slowing down the development of a fire before the full involvement of the room. This is done by the room’s local occupants.

Means:1. Fire Extinguisher2. Water Supply3. Fire Blanket4. Bucket of Sand

3Fire Growth Restriction

Manual Means of Restricting Fire Growth

5

BasicPrinciples 3Fire Growth RestrictionRating of Fire Extinguishers

4:

Class A Extinguishers will put out fires in ordinary combustibles, such as wood and paper. The numerical rating for this class of fire extinguisher refers to the amount of water the fire extinguisher holds and the amount of fire it will extinguish

Class B Extinguishers should be used on fires involving flammable liquids, such as grease, gasoline, oil, etc. The numerical rating for this class of fire extinguisher states the approximate number of square feet of a flammable liquid fire that a non-expert person can expect to extinguish

Class C Extinguishers are suitable for use on electrically energized fires. This class of fire extinguishers does not have a numerical rating. The presence of the letter “C” indicates that the extinguishing agent is non-conductive

Class D Extinguishers are designed for use on flammable metals and are often specific for the type of metal in question. There is no picture designator for Class D extinguishers. These extinguishers generally have no rating nor are they given a multi-purpose rating for use on other types of fires

BasicPrinciples 3Fire Growth RestrictionTypes of Fire Extinguishers

4:

Dry Chemical extinguishers are usually rated for multiple purpose use. They contain an extinguishing agent and use a compressed, non-flammable gas as a propellant

Halon extinguishers contain a gas that interrupts the chemical reaction that takes place when fuels burn. These types of extinguishers are often used to protect valuable electrical equipment since them leave no residue to clean up. Halon extinguishers have a limited range, usually 1.2 to 1.8 meters. The initial application of Halon should be made at the base of the fire, even after the flames have been extinguished

Carbon Dioxide (CO2) extinguishers are most effective on Class B and C (liquids and electrical) fires. Since the gas disperses quickly, these extinguishers are only effective from 1.0 to 2.4 feet. The carbon dioxide is stored as a compressed liquid in the extinguisher; as it expands, it cools the surrounding air. The cooling will often cause ice to form around the “horn” where the gas is expelled from the extinguisher. Since the fire could re-ignite, continue to apply the agent even after the fire appears to be out

BasicPrinciples

-Categories: General Use, Institutional, Residential, Attics, Special Hazards, Storage

-3 heads: upright, pendent and sidewall

-Rated to 175 psi

3Fire Growth Restriction

Mechanical Means of Restricting Fire Growth

6

Sprinkler Specifications:

Sprinklers can be spaced from 3.6 to 6.0 meters apart.

Assumes that measures to control a growing fire may not be successful, hence its maximum size needs to be restricted both to reduce the risk and to allow effective firefighting.

Extend CHB walls up to slab

Provide 1 m. ledge to prevent spread of fire

- providing a 1-meter ledge to prevent fire from creeping up exterior walls into the floor above through windows.

This implies:

1. Fire cladding of structural components to ensure stability of structural frames.

2. The use of fire-rated walls and slabs to contain fire in rooms, sub-compartments and compartments so as to segregate areas where fire may occur.

3. Others:

- plugging all holes; extending CHB walls up to the slab;

BasicPrinciples 4Fire Containment

Definition and Implication

Fire-Rated Surface

Compartment

Compartment Sizes

The more combustible the contents of a building, the smaller the compartment should be.

Joints must be filled with non-combustible materials to prevent the spread of smoke or flame.

Objectives-To limit fire and smoke spread-To allow longer escape time-To reduce the maximum potential size of the fire

Containing fire-prone areas by means of fire-

resistiveenclosures

Definition


Sub-Compartment

Concepts of Fire Compartmentation2

Room


Concepts of Fire Compartmentation

LEGEND:

Rooms

Department


Fire Rating of Construction Systems3

Gypsum Walls

-Two layers 16mm type X gypsum wallboard or veneer base applied to each side of 62mm metal studs 400mm O.C.

-Two layers 16mm type X gypsum wallboard or veneer base applied to each side of 50mmx100mm wood studs 600mm O.C.

-One layer 16mm type X gypsum wallboard or veneer base applied to each side of 40mm metal studs 600mm O.C.

-One layer 12mm type X veneer base nailed to each side of 50mmX100mm wood studs 400mm O.C.

SteelWoodSteelWood

2 Hour1 Hour

Concrete Masonry Wall Units4 Hour2 Hour

4” 6”



Ceiling Systems

12mm gypsum wallboard applied to drywall furring channels. Furring channels 600mm O.C., attached with 18 gauge wire ties open web steel joists 600mm O.C. supporting rib metal lath on 28 gauge corrugated steel and 62mm concrete slab.

12mm gypsum wallboard applied to drywall resilient furring channels 600mm O.C. and nailed to wood joists 400mm O.C. Wood joists supporting 25mm T&G finish floor.

3 Hour2 Hour1 Hour

12mm25mm

STEEL RUNNERS

3-16mm FIRE RATED PANELS

35mm x 22mm ANGLE RUNNER

CORNER REINFORCEMENT

WIRE MESH



-Flush Metal Door-No Glass Permitted-3mm clearance at jambs-10mm clearance at non-combustinle floor-For openings in fire walls or walls that divide a single building into fire areas

-Maximum glass area 0.063 sq.m-6mm thk Wire glass in a steel frame-For openings in enclosures of vertical communications through buildings and in 2-hour rated partitions providing horizontal fire separations

-Maximum glass area: 0.83 sq.m-For openings in walls or partitions between rooms and corridors having a fire resistance rating of 1 hour or less

3 Hour2 Hour1 Hour

Door OpeningsFor 1.2m X 3.0m single hollow metal doors (ga.20 steel face), with labeled single-point or 3-point latching hardware, steel hinges or pivots

1.370m max

0.83m max

125mm min

125mm min

*Insulated building elements will not ignite in fire and will ensure passage of human beings without damage on the other side of the separating element.

Ability to prevent heat transfer from one face to the other face.

Insulation

Temperature increase

Load Bearing Capacity

Collapse or excessive deflection

Structural Performance: Building still stands during an emergency

Ability to carry load without collapsing

Integrity

Passage of flame

Ability to resist the development of crack or perforations so as not to allow passage of smoke and flame


Load Bearing Capacity, Integrity and Insulation

2

Covers those devices and systems which aid firefighters in actively extinguishing the fire and bringing it to an end earlier than a free-burning fire.

ensure that all areas inside and outside the building are covered by reach of the firehose

BasicPrinciples 5Fire Control

Definition and Implication

access road for firetrucks

Access Road


Fire apparatus should have unobstructed access to buildings.

R

L

W

Bollards and fences used for traffic control must allow for sufficient open road width for fire truck

Site Access for Fire Control8:

30m> DEAD END

CUL-DE-SAC

T-TURN

Prevent time-consuming, hazardous back-ups at dead-ends by using T-turns and cul-de-sacs

MAX. 90 METERS

FIRE HYDRANT

Place hydrants at max. 3 meters from curb. Siamese connection to standpipes must be visible and within 60m from hydrant

SIAMESE CONNECTION

Utility poles, kiosks, sculpture, fountains, plant boxes can impede fire rescue operations

0.3m

Hydrant must be unobstructed; Fire hose connection should be at least 0.3m above grade

BasicPrinciples 5Fire ControlFiretrucks

75 ° (safeangle)

30 m

.

33 m.

Approx. 10 storeys8.5 m.

26 m.

75 °

25 m

.

Approx. 8-9 storeys6.7 m.

22 m.

75 °

20 m

.

Approx. 6-7 storeys5.6 m.

Aerial ApparatusSpecifications:

Provides access to a building, especially in high rise buildings, for fire brigades.

Is fully-equipped with firefighting equipment, service elevator, stair and lobby.

Provides a sufficiently secure operating base and a rest area in between firefighting operations.

Wet and Dry Risers

Elevator shaft

Fire-rated doors


Concept of the Firefighting Shaft

Measures which can assist to some extent occupants in the fire zone but are particularly needed for others in adjacent areas or compartments.

Techniques of Smoke Control

a. SMOKE CONTAINMENT/ BARRIER – technique of restricting the movement of smoke by the provision of fire resisting elements.

b. SMOKE DISPERSAL – technique of clearing smoke locally by provision of natural cross-ventilation or mechanical venting.

Make Up Air

Smoke Barrier

Smoke Plume

Shop

Mall

BasicPrinciples 6Smoke Control

Definition and Techniques2

Venting

Extraction of SmokeCeiling Reservoir

Low Pressure

High PressureUses barriers including

walls, floors and doors, to contain pressurized air generated by mechanical means to keep smoke away from protected areas such as escape staircases and corridors.

c. PRESSURIZATION – technique whereby air is blown into spaces which are designed to be kept clear of smoke.

BasicPrinciples 6Smoke Control

Definition and Techniques2

Cover a range of passive or active systems which permit the occupants to move or be moved to a place of safety within or to the outside of a building.

FIRE ESCAPE:fire escape stairs designed to be used daily for familiarity of escape routewell-maintained (not used as storage of junk)

CORRIDOR SYSTEM:direct, not tortuoussimple lay-outno barriers, cul-de-sacs, bottlenecksdoors open out, not ineasily detectible, not hidden from view

BasicPrinciples 7Escape Provisions

Definition

Escape Route Leading to:

Place of Safety

Place of Safety

StairwayEnclosure

c. Protected Stairway Enclosure

Place of Safety Place of Safety

Protected EscapeRoute

a. Protected Escape Route

Place of Safety

Place of Safety

Protected Lobby

b. Protected Lobby

To provide safety, the routes must

be properly protected from

the effects of fire and smoke for an

acceptable time period, usually a

minimum of 60 minutes.

This can be achieved by:

- Compartmentation

- Fire resistance of escape route structure

- Use of smoke control systems to keep smoke out of escape routes

Protected escape routes are designed in such a way that they lead to a place of safety, and once

inside the occupants are safe from the immediate danger from fire and smoke.


Protected Escape Routes1

Access through

Courtyards

exit courtyard

Alternative Means of Escape-Doors should be as far as possible from each other; preferably on opposite walls-Both doors should not open into the same compartment

compart-ment

courtyard

subcomp-artment subcomp-

artment

subcomp-artmentsubcomp-

artment

Place of Safety

Place of Safety


Alternative Means of Escape1

Reqd. width of escape route

Additional width to allow for door swing

Design width

Design width

90° min

90° min


Design of Fire Resisting Doors1

1. The presence of patients with various degrees of dependency and immobility on one hand and the constant presence of staff on the other.

2. It is assumed that there should be no reliance on external; rescue or such manipulative types of escape appliances as chutes or fire ladders.

3. The staff would be fully responsible in assisting patients within their area of control to a place of safety in an emergency.


Primary Considerations in theDesign for FIRE

Safetyof Hospitals1


Progressive Horizontal Evacuation1

END

FIRE SAFETY PRINCIPLES

5 fire safety principles

Design

load areas areas

high life risk areas

rapid spread

spread offire

high life riskhigh

high conductivity spreadsheat

construction materials

capacity of materials