Ch. 2 Building Classifications and Structural Fire Resistance Flashcards Preview

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Flashcards in Ch. 2 Building Classifications and Structural Fire Resistance Deck (34)
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1
Q

Factors that influence fire behavior

A

Basic building classifications
Occupancy classifications
Fire or fuel load
Fire resistance

2
Q

5 major classifications

A
Type I - Fire resistive
Type II - Noncombustible or protected noncombustible
Type III - Exterior protected (masonry)
Type IV - Heavy timber
Type V - Wood frame
3
Q

Classification can help …

A

… firefighters determine the likelihood of structural collapse under fire conditions. They also indicate the degree of occupant safety provided by the building’s construction

4
Q

Classification and subclassifications of 3 digit numbers …

A

First digit - Fire resistance rating (in hours) of exterior bearing walls
Second digit - Fire resistance rating of structural frames or columns and girders that support loads of more than one floor
Third digit - Fire resistance rating of the floor construction

5
Q

Type I (Fire Resistive)

A

Classified by the presence of noncombustibles structural components that have fire resistance ratings within a specified range.

6
Q

Steel is a noncombustible …

A

… but not fire-resistive and must be protected to attain fire resistance

7
Q

Fire resistance …

A

… increases structural integrity during a fire

8
Q

Fire resistive …

A

… compartmentation provided by partitions and floors tends to limit or slow the spread of fire through a building.

9
Q

Examples of variation in fire-resistance

A

Bearing walls, columns, and beams - 2 to 4 hours, as specified by the local code and the construction classification
Floor construction - 2 or 3 hours
Roof deck and construction supporting the roof - 1 to 2 hours
Interior partitions enclosing stairwells and corridors - as specified by the local code : usually 1 to 2 hours
Partitions separating occupancies or tenants - as specified by local code

10
Q

Type I buildings …

A

…are most commonly constructed using a protected steel frame or reinforced concrete. Unprotected steel has no fire resistance. When steel is used in fire-resistive designs, it must be protected by an insulating material. The combination of the structural strength of steel and the insulation produce a fire-resistive structural assembly.

11
Q

Combustible material permitted are . . .

A
Roof coverings
Interior floor finishes 
Interior wall finishes and trims
Doors and door frames
Window sills and frames 
Platforms
Nailing and flurring strips
Light-transmitting plastics
Foam plastics subject to restrictions
12
Q

Type II Construction …

A

… allows a wider range of materials than Type I. In addition to steel and concrete block, glass and aluminum can be used with a limited structural role.

13
Q

Some building codes …

A

… contain a provision to omit the fire-resistive rating for a roof construction for some occupancy types when the roof is located more than 20ft above the floor. This can cause a Type II (non-combustible) building to be classified and inspected as a Type I (fire-resistive), which can be significant in the event of a fire.

14
Q

Type II - A (protected)

A

Require that structural components have one-hour fire resistance

15
Q

Type II - B (unprotected)

A

… allows structural components to be unprotected, meaning the major structural components have NO fire-resistance. The use of unprotected steel is the most common characteristic of unprotected, noncombustible construction

16
Q

The speed unprotected members will fail …

A

… depends on …
Ceiling height of the building
Size of the unprotected steel members
Intensity and duration of the exposing fire

17
Q

Type III - Exterior Protected/Ordinary

A

Frequently constructed with exterior walls of masonry, but any noncombustible material with the required fire-resistance can be used for the exterior walls.

18
Q

Type III Interior …

A
... structural components that are permitted to be partially or wholly combustible include :
Walls
Columns
Beams
Floors
Roofs
19
Q

Fundamental fire concern …

A

… with Type III construction is the combustible concealed spaces that are created between floor and ceiling joists and between studs in partition walls when they are covered with interior finish materials.

20
Q

Type III confined spaces …

A

… must contain appropriate fire stops

21
Q

Type IV Construction (mill construction) …

A

… is made of Heavy Timber. Like Type III construction, the exterior walls are normally made of masonry and the interior structural components are combustible

22
Q

Main differences between Type III and Type IV

A

Type IV construction - beams, columns, floors, and roofs are made of solid or laminated wood with dimensions greater than in Type III construction.

Concealed spaces are not permitted between structural components in Type IV construction

23
Q

Type IV does not use A and B subdivisions …

A

… designated 2HH is used instead.

24
Q

Type V construction

A

All major structural components are permitted to be of combustible construction. Many are required to have a 1-hour fire-resistance for structural components

25
Q

Fundamental problem with Type V construction …

A

… is the presence of extensive concealed voids.

26
Q

Light frame construction …

A

… was introduced in 1830s and is considered “the common currency of small residential and commercial buildings in North America today”

27
Q

Mixed construction …

A

… occurs where a new structure is built onto an existing structure of a different construction type

28
Q

Building construction and occupancy classification …

A

… are used together in building codes to establish limitations on the permissible heights and open areas of buildings

29
Q

12 Major Occupancy Classifications

A
Assembly
Educational
Day care
Health Care
Ambulatory health care
Detention and correctional
Residential
Residential board and care
Mercantile
Business
Industrial
Storage
30
Q

Fuel load …

A

…the total quantity of combustible material in a compartment

31
Q

The fuel load contributes to …

A

… the calculation of the fire load, the maximum amount of heat that can be released if all fuel is consumed.

32
Q

The fire load will vary …

A

… depending on the heat of combustion of the fuel load

33
Q

The fire load can be used …

A

… as an estimate of the total potential heat release or thermal energy to which a building may be subjected to if all combustibles become fully involved in fire.

34
Q

Buildings with combustible structural components …

A

… have an inherently greater fire load than noncombustible construction because the structural framing materials contribute a significant amount of fuel to a fire