means of egress system

Building Design and Construction

FIRE 1102 – Principles of Fire Science Reference: Chapter 4 of Cote, Fundamentals of Fire Protection

UAE Tamweel Tower

Objectives of Fire-Safe Building Design

1. Life Safety

2. Property Protection

3. Continuity of Operations

4. Environmental Protection

5. Historical Preservation

Life Safety • Achieved by early warning of a fire, extinguishment

of a fire, proper egress for prompt escape

• Can the occupants get out before the room becomes untenable?

– We know that flashover is a time when the room is untenable,

– However there may be a time before flashover where a room is untenable where concentration of fire gases (CO) can create such a situation.

• We can do modeling of how long it takes for occupants to evacuate out of a building and predict when a room becomes untenable.

• Human Behavior Research

Fire Modeling of Station Night Club Fire

Human Behavior Research

Property Protection • Materials that can be replaced which have a dollar

value assigned to them.

• Billions of dollars are lost due to fires each year.

• Achieved by installing proper fire extinguishing systems, compartmentation features to limit spread and construction of building materials.

Heritage Preservation

• Irreplaceable items and artifacts.

• Accomplished using appropriate fire extinguishing systems.

Mona Lisa Original Copy of Declaration of Independence

Hand Written Quran National Museum of Saudi Arabia

Continuity of Operations

• Getting back to business

• Accomplished by installation of proper fire extinguishing systems

Environmental Preservation

• Protecting our environment from fire and/or fire extinguishing agent.

• Installation of fire extinguishing systems that limit fire size, minimize run-off from water, using agents that do not adversely affect the ozone layer.

Types of Building Construction

• NonCombustible Construction

– Type I

– Type II

• Combustible Construction

• Type III

• Type IV

• Type V

Type I Construction Non-combustible

• Fire Resistive • Constructed of concrete

and protected steel • Columns and beams are

covered with fire resistive spray on material.

• Primary hazard are the contents in the structure.

• High-rise office buildings, shopping centers

Type II Construction Non-combustible

• Non-Combustible • Lower degree of fire resistance than

Type I. • Fire resistant rating on all exterior

and interior load bearing walls. • May have combustible non-

loadbearing partition walls. • Columns and beams are not

protected and will be exposed during a fire.

• Office buildings, warehouses, automobile repair shops.

Type III Construction Combustible

• Ordinary Construction

• Office buildings, retail stores, mixed occupancies with store on first floor and dwelling on second floor.

• Exterior walls of the building have 2-hr fire resistance rating and non- combustible

• Interior members (walls, beams, floors, roof) are made of wood

• Hazards: smoke and fire spread through concealed spaces

Type IV Construction Combustible

• Heavy timber (mill construction)

• Exterior/interior walls noncombustible material

• Interior structural members (beams, columns, arches, floors) made of solid or laminated wood with no concealed spaces

• Found in old factories, warehouses, churches

Type V Construction Combustible

• Frame construction

• Exterior and interior structural members made of wood

• Fire Hazard: unlimited potential for fire extension, fire extension to nearby structures

• Typical residential home

Construction Materials

Wood

• Combustible • Char forms at surface (acts as insulator)

– Good for heavy timber

• Used as different building elements – structural material – Siding – Flooring – Roofing underlayment – Interior finish – Furniture

https://www.youtube.com/watch?v=a3Q3wwRAGiw Great Chicago Fire 1871

Steel • Used to form frame of building

– Beams, girders, columns, bar joists

• Noncombustible

• Expands when exposed to heat

• Conducts heat

• Loses 40 – 50% of its strength when exposed to temps of 900 – 1100 °F

• Most codes require steel to be protected with sprinklers

• May be protected by encasement, spray-on, gypsum

Concrete Masonry

• Mixture of cement, water, and aggregate (rocks/stones)

• Very fire resistive but can spall when water is forced out of the concrete.

Glass

• Not fire resistive, but resists passage of smoke.

• Improve resistivity by adding wire mesh into the glass.

• Fire-rated glass will have

Gypsum and Plaster

• Plaster made from gypsum rock, crushed and ground into powder – Water added to create paste-like

substance

• Gypsum board – Sheetrock, drywall

• Excellent fire resistive protection – Water is major component

• Must make certain that penetrations (holes) are filled in. – Fire and smoke can pass through

holes in the wall.

Fire Testing of Building Materials

• ASTM E119 – Standard Test Method for Fire Tests of Building Construction Materials

– https://www.youtube.com/watch?v=lW72-L0_n_M

– ASTM (American Society for Testing and Materials)

• Involves placing floor, wall, roof or door assembly into a furnace and subjecting it to the heat rates specified in the time temperature curve for the duration desired.

Time Temperature Curve

• Fire severity expressed in terms of temperature and duration.

• This curve represents a severe building fire.

• Required fire ratings are prescribed in codes that advise as to how long a door, wall floor, etc. can withstand a fire.

Flame Spread Ratings • The materials first involved in fire

ignition or spread are the contents, furnishings, and interior finishes.

• Materials that are used as interior finish on walls and ceilings must meet certain standards to resist fire spread.

• Materials are tested in a device called Steiner Tunnel

• Flame spread rating is a relative measure of how material will allow fire to spread across the surface. – Rating of 0 –25 Class A (Cement

asbestos has a rating of 0) – Rating of 26 – 75 Class B – Rating of 76-200 Class C (Road oak

has rating of 100)

Smoke Spread • Control of smoke is important from both life

safety and property protection standpoint. • Smoke management does following things:

– Maintain tenability in means of egress system – Confine smoke spread to area or compartment of

origin – Assist firefighting operations by maintaining

conditions outside fire area – Reduce property loss and minimize business

interruption.

• Accomplish smoke management via – Pressure differential across physical barrier – Remove smoke by large volume air flows – Dilute smoke with “fresh air”

Mechanical Smoke Control System , Santa Monica, California https://www.youtube.com/watch ?v=a3Rg4VJVVfI