Chapter 3 Building Construction Flashcards
Types of Building Construction
Type 1- Fire-resistive Type 2- Noncombustible or limited combustible Type 3- Ordinary Type 4- Heavy Timber Type 5- Wood Frame
Type 1
Fire Resistive
Provides structural integrity during a fire
- Structural members, including walls, columns, beams, floors & Roofs made of noncombustible or limited combustible materials.
- Fire-resitive compartmentation provided by partitions & floors tend to retard the spread of fire.
- Primary Hazard “Contents”
- FF can launch an interior attack with confidence
- Fire can spread by opening in partitions & improperly designed heating & cooling systems.
Type 2
Noncombustible or limited combustible
Similar to type 1. Degree of fire resistance is lower.
- Fire resistance ration on all parts of structure (exterior & interior load bearing walls, building materials.
- No fire resistance rating such as wood “can be used in limited quantities”
- Primary concerns, contents of building, Heat can cause structural supports to fail, Type of roof “Flat built-up roofs. Felts, insulation & tar
Type 3
Ordinary
-Exterior walls & structural members constructed of noncombustible or limited combustible materials.
- Interior members (Walls, Columns, Beams, Floors & Roofs are completely or partially wood.)
- Primary concern- Fire and Smoke spreading through concealed spaces.
Type 4
Heavy Timber
- Exterior & Interior walls & their associated structural members made of noncombustible or limited combustible materials.
-Other Interior structural members, including, Beams, Columns, Arches, Floors & Roofs, are made of solid or laminated wood with no concealed spaces.
(Old factories, Mills, Warehouses, Churches)
*Primary Hazard= Massive amounts of combustible contents, Tremendous amounts of Heat & Exposure protection problems.
Type 5
Wood Frame
-Exterior walls, bearing walls, floors, roofs & supports made completely or partially of wood or other approved materials.
- Commonly typical single-family residence
- Unlimited potential for fire extension with building of origin & to nearby structures
-FF must be alert for fire coming from doors & windows extending to the exterior of the structure.
Load Bearing Wall
Walls that take loads (Party walls)
Most exterior walls are load bearing walls
Party Wall
A load bearing wall that supports two adjacent structures.
Partition Wall
Divides two areas within a structure and is a non-load bearing wall
Wood
Reaction of wood to fire conditions depends on two factors
- Size of Wood
- Moisture content ( Green Wood)
Masonry
Bricks, Stones, Concrete ( Minimally affected by fire & Exposure to high temps)
- Commonly used for Fire Wall assemblies
Cantilever Wall
Free standing fire walls commonly found on large churches & shopping centers
Block Wall
May be load-bearing walls
Most Brick and stones walls are Veneer walls
Veneer Wall
Decorative & usually attached to the outside of some type of load-bearing frame structure.
Bricks
Stones
Blocks
- Rarely show any signs of floss of integrity or serious deterioration
- May Spall or lose small portions of their surface when heated
- May Crack but usually retain most strength & basic structural stability
- Motor between bricks, blocks, & stone are subject to more deterioration
Cast Iron
Rarely used in modern construction
*Primary Concern is stand pipe bolts or other connections can fail
Steel
Primary material used for structural supports in modern buildings.
- Elongate when heated (50’ beams may elongate as much as 4” @ 1000 degrees)
- If restrained @ ends it buckles & fails somewhere in middle.
Reinforced Concrete
Internally fortified with steel reinforcement bars or mesh.
- Doesn’t perform particularly well under fire conditions. Loses strength & Spalls
Gypsum
Inorganic product from which Plaster & Plasterboards are made
- High water content
- Provides insulation to steel & wood
Glass/Fiberglass
- Wire-reinforced glass has some thermal protection
- Typically used for insulation purposes
Two primary types of dangerous conditions that may be posed by a particular building
- Conditions that contribute to the spread & Intensity of the fire
- Conditions that make the building susceptible to collapse
Fire Load
Maximum heat that can be produced if all the combustible materials in a given area burn.
Heavy Fire Loading
Large amounts of combustible materials in an area of a building.
- Most critical hazard in commercial & storage facilites can quickly override sprinkler systems.
Collapse zone
One and a half times the height of the building
Lightweight & Truss Construction Hazards
Two most common
Usually fail in 5-10 minutes
-Lightweight metal steel bar bent at 90 degree with flat or angulated welded to top and bottom
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- Lightweight wood 2x3 or 2x4 connected by gussets.
Gusset Plates
Small metal plates (18 to 22 gage) with prongs that connect into wood 3/4”
Bow String Tusses
Building with large openings (car dealerships, Bowling alleys, Factories & Supermarkets)
Trusses are designed to work as a integral unti
- Some are in tension (Vertical & Horizontal stresses that tend to pull things apart)
- Some are in Compression ( Vertical & Horizontal stresses that tend to press things together.)
Construction, Renovation & Demolition
- Additional fire load & ignition sources( Open flames, Torches, Grinding, Cutting) by contractors
- Subject to rapid fire spread while partially completed, lack of doors and widows spread fire
- Arson, Poor house keeping prevents egress.
