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BUILDING CONSTRUCTIONIFSTA : Chapter 3

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BUILDING CONSTRUCTIONIFSTA : Chapter 3

• Additional reading:– IFSTA Essentials #4 – chapter 8, 9, 10

• Only for the information relating to building construction

• Some quiz, midterm and final questions will be from this material

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Learning Objectives• List and define five types of building construction.

• Identify the effects fire has on common building materials to enable firefighter’s to effectively attack the fire.

• Identify the different occupancies and their effects at a structure fire.

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Learning Objectives

• Identify the hazards of building construction during fire suppression operations.

• Identify construction features during size up.

• Identify indicators of structural failure or collapse during fire suppression operations

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Types of Building Construction

• Most building codes have 5 types of building construction.

• Many buildings include several types of construction.

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Type I: Fire Resistive Construction

• Structural members made of noncombustible / limited combustible materials.

• Construction intended to confine fire and its byproducts to a given location.

• Primary fire hazard is contents of structure.

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Type II: Noncombustible Construction

• Lower degree of fire resistance than type I.

• Fire resistance rating on all exterior and interior load bearing walls.

• May have combustible features, as materials with no fire resistance rating may be used.

• Generally have flat roofs with combustible felt, insulation and roofing tar.

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Why is Size-up Important?

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Type III: Ordinary Construction• Exterior walls & structural

members of noncombustible / limited combustible materials.

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

• Hazards: smoke and fire spread through concealed spaces.

• Fire stops to limit spread.

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Type IV: Heavy Timber• Exterior / interior walls

noncombustible material.• Interior structural members

(beams, columns, arches, floors etc.) made of solid or laminated wood with no concealed spaces.

• Found in old factories, warehouses, churches.

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Type V: Frame Construction

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Type V: Frame Construction

• Exterior and interior structural members made of wood.

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

• Typical residential home

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Platform Frame

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“Silent Flooring”

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Poor Construction Methods

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Fire Effects on Common Construction Materials – Wood

• May be used in load bearing and non-load bearing walls.

• Reaction of wood to fire conditions is based on the size of the wood and its moisture content.

• Water does not have a negative effect on wood’s structural strength.

• Plywood, particle board, paneling may be highly combustible, produce toxic gases and rapidly deteriorate under fire conditions.

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Fire Effects on Common Construction Materials -

Masonry• Brick, concrete, and stonework.• Commonly used for firewalls to separate connected

structures and prevent fire spread.• May be used as load bearing or veneer.• Minimally affected by fire & high temperatures.• Mortar joints between bricks, blocks may

deteriorate. (mortar mix is weakest part of wall)• Rapid cooling of masonry by water may cause

cracking or spalling.

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Fire Effects on Common Construction Materials - Concrete• Concrete is a mixture of portland cement, sand,

gravel and water.• Often used as a fire resistive protection for

structural steel (reinforced concrete).• May crack or spall if heated, indication of damage

& reduced strength.• Heating may cause bond between steel and

concrete to fail.• Concrete tends to absorb and retain heat.

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Fire Effects on Common Construction Materials –

Reinforced Concrete

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Fire Effects on Common Construction Materials - Steel

• Primary use of steel is for structural members.

• Steel is an excellent conductor of heat.• Steel loses strength as temperature increases• Steel structural members will elongate

when heated.• Water can cool steel structural members and

reduce risk of failure or collapse.

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Fire Effects on Common Construction Materials - Steel

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Fire Effects on Common Construction Materials - Plastic

• Becoming integrated to replace/improve common building materials

• Plastics are oil-based (hydrocarbons)• Two general types

– Thermoplastics (melt, deform, vapourize = burns!)

– Thermosets (decomposes, only burns with extreme temps)

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Fire Effects on Common Construction Materials - Plastic

• General Rule of Thumb when fighting fires involving plastics…– Burn fast

– Very intense heat

– Dense black smoke

– Extremely toxic

• Can resemble a Class B Fire (flammable liquids)

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BREAK TIME

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Roof Types

Three Main Types:(a) Flat(b) Pitched(c) Arched

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Occupancy Versus Type of Construction

• Occupancy creates the fire load.• Building codes specify building type based

on occupancy classification.• Fire code determines fire protection based

on building and occupancy use.• Occupancies are residential, commercial,

business, industrial and educational.• Each type has a number of hazards.

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Occupancy Hazards

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Building Uses

• Ontario Fire Code and Ontario Building Code separate buildings in groups A-F, as related to their major use (or major occupancy)

• With each type of building comes various requirements/restrictions on building construction

• Private dwelling residences are exempt (with some exceptions)

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Building Uses

• A – Assembly– Theatres, libraries, schools, large bars, pubs and restaurants

• B – Institutional (compelled to sleep over)– Jails, hospitals, orphanages, nursing homes

• C – Residential– Apartment buildings (common area) , group homes, houses, motels

• D – Business and Personal Services– Banks, barber shops, offices (medico legal), laundromat

• E – Mercantile– Markets, stores, shops, supermarkets, restaurants, bars and pubs

• F – Industrial– Flammable liquid plant, television studio, freight depot

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Firefighter Hazards:Structure Fires

• Change in occupancy creating an unusually heavy fire load.

• Dangerous stockpiling and excessive stock creating access problems.

• Unknown design errors, renovations, contractor short cuts.

• Arsonists traps or tampering with fire protection systems.

• Occupancy may not be what it appears. (drug lab, boarding house, group home, etc.)

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Construction Features Assessed During Size Up

What constructions features are important during size-up?

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Construction Features Assessed During Size Up

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Firefighter Hazards:Structure Fires

• Combustible furnishings & finishes.• Wooden floors / ceilings.• Large open spaces.• Synthetic materials.

• Lightweight & truss construction.

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Lightweight Wood or Steel Truss Construction

=Very Dangerous Firefighting

Conditions

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Truss Roofs

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Bowstring Truss!

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Beware of the Truss!

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Structural Collapse

• Every structure fire has the potential for collapse.

• Firefighters must be aware and look for indicators to collapse.

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Signs of Potential Collapse

• Prolonged exposure.(time)

• Distorted structural members.

• Fire on floors below heavy machinery and heavy loads.

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Signs of Potential Collapse

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Building Collapse Zone

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Size Up – What do you see?

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The Back?

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The Side?

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Summary

• Firefighters must know & understand building construction.

• There are five common types of construction.

• Firefighters need to be aware of the hazards associated with structure fires.

• Effects of fire on building materials.• Signs of structural collapse.