Training Fire Protection

8/10/2019 Training Fire Protection

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AIA Middle EastA309

Life safety- engineeringmeans of egressBahrain

Allan ComelloApril 17, 2013


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This presentation is protected by US and International Copyright laws.Reproduction, distribution, display and use of the presentation without written

permission of the speaker is prohibited.

Trinity Bahrain 2013

Copyright Materials


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1) Illustrates the safety challenges posed by high-rise buildings

2) Describes the requirements for fire protection and prevention

3) Describes system & design requirements, as per the standards,of Smoke Management Systems

4) Explains stair pressurization, components, and its working

5) Discusses passive fire safety elements in the building as a first line ofdefense in fire emergencies

6) Proposes strict adherence to standards and quality procedures for design,specification, installation and maintenance of stairwell pressurization componentsfor a safe means of egress

Course

Description


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Learning

Objectives

1. Participants will learn about safety challenges posed by high-rise buildings

2. Participants will have an understanding of the design specifications and

systems requirements of stairwell pressurization system as per the safetycodes and standards

3. Participants will gain knowledge about stairwell pressurization as an effectivesmoke management method in high-rise buildings

4. Participants will learn from the on-site experiences and examples provided


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Presenter: Allan Comello

LIFE SAFETY

Engineering Means of Egress


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"Any building greater than 23 meters (75.5 ft) in

height, where building height is measured from the

lowest level of f ire department vehicle access to the

floor of the highest occupiable story.

- NFPA 101 Life Safety Code (LSC) 3.3.27.7

High-rise building

NFPA : Height > 23m

I.B.C.: Height > 23m


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Each year, an estimated 15,500 high-rise structure fires cause60 civilian deaths, 930 injuries, and $252 millionin property loss

Three-quarters of high-rise fires are in residential structures

The leading cause of all high-rise fires is cooking (38%)

Four property types make up 50% of the high-rise firesreported (Apartments 44%, Hotels 2%, Hospitals, Clinics,doctors offices 2%; Other offices 2%)

69% of high-rise structure fires originate on the 4th floor or

below; 60% occur in apartment buildings; 43% originate in thekitchen

High-rise fires are inherently more difficult for occupantevacuation

Sources: NFPA and NFIRS

High- rise buildings- Fire statistics


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Challenges posed by high-rise fires

Temperature gradients leading to varying pressures throughoutthe structure result in rapid spread of smoke and flame

Fire fighting in multiple types of occupancies, includingresidential, commercial, restaurant, and underground parking,need to be approached differently

By design, exits from high-rise structures are limited. Thismakes the movement of people out of a building difficult inan emergency

Improper Installation, sequencing and irregular maintenanceof HVAC, Fire Fighting System & Fire Detection System

High-rise structure fires require significantly more personneland equipment to extinguish than do other types of fires


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Safe egress concerns

Fire extension & smoke spreadStack effectInadequate systemsand evacuation method

Engineering means of egress


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Fire extension & toxic smoke spread

Vertical design of high-rise buildings is susceptible to rapid fire extension

Common avenues for f ire spread

Poke-thru construction

Lapping

Radiated heat through flooring

HVAC ducting The gap between the exterior panels

and interior beams


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Fire & smoke spread rate

Fire can travel up to 70mph.

Smoke can travel at a speed of over 2m/s, this isfaster than the probable escape speed of an occupant


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Stack effect

Stack effect is defined as " the vertical, natural airmovement throughout a high-rise building caused

by the difference in the outside and inside air

temperatures.

Positive stack effect

Negative stalk effect

Influencing factors:

Airtight exterior walls

Air leakage between floors

Air temperature between floors

Differences between inside and outside

air temperature


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Inadequate Systems

Smoke management systems are required to meet specific

building codes for fire resistance. Failure of these systems canhinder fire department operations resulting in a large fire.

Active fi re protection systemsSmoke detectorsFire alarms systems

Sprinkler systemsHVAC systems

Passive fire protection systemsStair & lift lobby pressurizationFire resistant doors

Fire walls/ barriersFire dampersMotorised Smoke & Fire DamperSmoke Exhaust System at fire floor


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Methods of smoke control

Dilution

Buoyancy

Compartmentation

Smoke exhaust at fire floor

Purpose of Smoke-Control Systems

Inhibiting migration of smoke out of the source compartment

Inhibiting smoke from entering means of egress (maintainingtenable environment for evacuees) Maintaining a tenable environment outside of the sourcecompartment for emergency personnel

Protecting life Reducing damage to property

-NFPA 92A (2000)

Pressurization

Ai rflow (HVAC)


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Stairwell pressurization

A type of smoke-control system in which

stair shafts are mechanically pressurized,with respect to the fire area, with outdoor

air to keep smoke from contaminating

them during a fire incident.

- NFPA 92 A

ComponentsStair Pressurization Fans

Ductwork and Accessories

Pressure Relief Dampers

Fire Alarm Systems

Fire rated doorsBuilding Automation Systems (BAS)

Source: NFPA


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Working of Stairwell

Pressurization

1) Under normal conditions, the pressurization fan should not run and the dampers on the airintake and bypass ducts shall be closed

2) In a fire situation, through a signal from the fire alarm panel, the damper on the air intake

shall open . An end switch on the damper actuator shall signal the fan to run when thedamper is open

3) A pressure sensor installed in the stairwell shall control the bypass damper to maintain aconstant pressure of 50Pa within the stairwell

4) The fan should be wired for manual stopping5) It should be possible to override all controls and run the system through the firemans smoke

control panel

Roof

Fire Alarm Panel

Fire Mans smoke

Starter / ControlPanel

Staircase

Bypass Duct

Source: Trinity


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Stair pressurization fansStair pressurization systems utilize a single

fan with a ducted shaft to multiple injectionpoints or multiple fans distributed over theheight of the stair. Smoke exhaust fans mustbe rated and certified by the manufacturer forvarying temperatures to which they areexposed. The fans must have smokedetectors in their inlets to stop them from

injecting smoke into a protected compartment.

Fan status and on-off-auto override switchesare required at the firefighters smoke controlpanel. Excess pressures could deactivate fansystems, making them unusable for smoke

control.


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Egress system design, installation & coordination

Coordination between fans and dampers in smoke control systemsrequires consideration of the installation geometry, control sequence ofoperation, and sensor locations.

Mechanical and electrical concerns:

Fan volume and pressuresDamper tolerance to the pressuresStraight duct entrances to the equipment


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NFPA standards for HVAC equipment

HVAC equipment used for smoke control purposes shall bepermitted to be located within the conditioned space, withinadjacent spaces, or within remote mechanical equipment rooms.

HVAC systems used for smoke-control purposes shall beprovided with outside air for pressurization.

Where supply and return air systems are interconnected as partof normal HVAC operation, smoke dampers shall be provided toseparate the supply and exhaust during smoke-control operation.

Smoke dampers used to protect openings in smoke barriers orused as safety-related dampers in engineered smoke-controlsystems shall be listed and labeled in accordance with UL 555S.

Standard for Smoke Dampers. 92A


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Motorised Smoke & Fire Dampers (MSFD)The dampers used in smoke control systems mustbe Motorised Smoke & Fire Dampers and listed to

UL555S. They need to be evaluated for their abilityto operate under anticipated conditions of systemoperation. The connections to and from fans anddampers must take system effect into account. Highpressure losses due to construction geometry cancause insufficient pressure. Motorised Smoke & Fire

Dampers actuate with pneumatic actuation andelectrical actuation.

Emergency lighting

In buildings where artificial lighting is provided fornormal use and occupancy, exit lighting and the

illumination of the means of egress is required toassure occupants can quickly evacuate the building.

All emergency lighting must be installed and tested inaccordance with NFPA 111 (Full 1 hour test annuallyand 30-second test every 30 days.)


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Fire rated doors ensure adequatecompartmentation of buildings tocontain fire in the compartment inwhich it starts providing a means ofescape .

Fire Doors are regulated by thebuilding code and NFPA throughoutdesign, specification, installationand occupancy permitting.

Compartmentation &

Fire resistant doors


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Fire rated doors- codes and standards

Doors from the building to the smoke proof enclosures vestibule must be 1 -hour fire rated.-IBC 1020 and NFPA 101

Doors from the smoke proof enclosures vestibule to the stairwell must be not less than 20-minute fire rated.-IBC 909 and 909

Stairwell doors, which can be locked, must be provided with automatic electrical unlocking from the centralstation. Telephones or other two-way communication systems must be provided at not less than every fifth

floor inside the stairwell.-IBC 403

Provide a sign at each floor level landing five feet above the landing that is visible when the door is openedor closed. The sign must indicate the floor level, the terminus of the top and bottom of the stair enclosure,and the identification of the stair.-NFPA 101

Doors located in smoke barriers shall be self-closing or shall be arranged to close automatically upon the

activation of the smoke control system.- NFPA 92A-5

Stairwell pressurization systems shall be designed to achieve the required pressure difference with a singledoor open to the interior of the building.- NFPA 92A-5


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The components of the means of egress shouldstrictly adhere to quality standards and NFPAspecifications

It is critical that on an outbreak of fire the

components of the means of egress have thecapacity to withstand fire and pressure variations

Openings in smoke barriers, number of doors open,door capacity and resistance are integral to safe exit

Guidelines to be followed for installing fire doors,frames and hardware at the stairwell opening

Design & engineering of egress components


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The required capacity of the pressurization fansincreases as area created by a partially open

stairwell door increases

Designs shall incorporate the effect of outdoortemperature and wind on the performance of thesmoke management system.

A door in a means of egress should be side-

hinged and must swing in the direction of theexit

Locks on doors in the means of egress shallopen the door with not more than one releasingoperation

A latch or other fastening device on a door shallbe provided with a releasing device that can bereadily operated under all conditions.


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Facility Managers should keep vigil on theuse of quality fire safety items

manufactured by certified and experiencedcompanies.

Fire alarm system to be designed, installed,

inspected, tested, and maintained per

NFPA 72

Luminescent markings to egress pathsas per NFPAs Life Safety Code will helpbuilding occupants reach an exit faster


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Lessons learnt from on-site experience

There should be separate ducts for stairwell pressurization rather than usingMasonry Shaft for air to avoid air leakages and get proper pressurization.

All ducts used for Pressurization and Smoke Exhaust System shall be firerated, many contractors are using normal GI Ducts which defeats thepurpose.

Elevator hoist ways have proved to be readily available conduit for movementof smoke throughout buildings in past fires. This is because the leakagethrough elevator doors and elevator hoist ways. The building stack effect hasprovided the driving force that has readily moved smoke into and out of theloosely constructed elevator hoist ways. Methods of correcting this problem

include:1) Exhaust of the fire floor

2) Pressurization of elevator lobbies

3) Construction of smoke tight elevator lobbies

4) Pressurization of the elevator hoist way

5) Closing elevator doors after automatic recall


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Lack of periodical testing and maintenance of the egress components lead tosystem failure. A written record of the inspection shall be signed and kept for

the annual inspection of the local authorities.

Functional testing of fire door and window assemblies shall be performed bycertified companies.

Adequate latching and closing force need to be maintained for doors


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Inadequate or faulty Smoke Management Systems often lead tolarge fire

Commonly observed flaws include: The failure of one component often leads to the failure of

other fire protection systems

Improperly set pressure reducing valves

Electrical system failure

It is paramount that local legislation imposes strict rules for the properinstallation, maintenance and service of fire safety items that are part ofthe means of egress


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References

NFPA 101- Standards for Life Safety

NFPA 80 - Fire door assembly inspection NFPA 80- Fire Doors and other opening

NFPA 101- Occupancy classification

AHRAE Chapter 52- Fire and Smoke Management.

NFPA 90 A- Standard for Installation of Air Conditioning and Ventilation Systems

NFPA 92A- Recommended practice for smoke control systems

NFPA 105- Standard for Smoke Door Assemblies and Other Opening NFPA 252- Standard Methods of Fire Tests of Door Assemblies

Wild, J.A., Fans for Fire Smoke Venting, Woods Air Movement Ltd

Technical Paper WTP20,1989

Klote, J.K. and Milke, J.A., Design of Smoke Management Systems,

American Society of Heating, Refrigerating and Air-conditioning

Engineers, 1992. Felker, Larry, Heating/Piping/Air Conditioning Engineering, 2004.


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This concludes The American Institute of ArchitectsContinuing Education Systems Course

Allan Comello+971509204011

Training Fire Protection

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