2- Building Construction- Building Classifications and Structural Fire Resistance Flashcards
NFPA 220 details the requirements for each of the classifications and subclassifications of building construction. In it, each classification is designated by a three-digit number code. For example, Type I construction can be 4-4-3 or 3-3-2. What do these numbers mean?
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
Type ____ construction is classified by the presence of noncombustible structural components that have fire resistance ratings within a specified range.
Type I (fire-resistive)
When it pertains to Type I construction, examples of the variation in fire resistance by application include:
A) Bearing walls, columns, beams: _ to _hours
B) Floor construction: _ or _ hours
C) Roof deck/construction supporting the roof: _ to _ hours
D) Interior partitions enclosing stairwells and corridors: usually or hours
E) Partitions separating occupancies or tenants:
A) 2 to 4 hours
B) 2 or 3 hours
C) 1 to 2 hours
D) Usually 1 or 2 hours
E) As specified by local code
Type I buildings are most commonly constructed using a ________ frame or ________.
Protected steel ; reinforced concrete
Unprotected _____ has no fire resistance. When it is used in fire-resistive designs, it must be protected by an insulating material.
Steel
______ is an inherently noncombustible material with good thermal insulating properties.
Concrete
In Type I construction, combustible materials typically are permitted for such uses as:
Roof Coverings
Interior Floor Finishes
Interior Wall Finishes and Trims
Doors and Door Frames
Window Sashes and Frames
Platforms
Nailing and Furring Strips
Light-transmitting plastics
Foam Plastics subject to restrictions
Type II construction allows a wider range of materials than Type I. In addition to steel and concrete block, ____ and _____ can be used with a limited structural role.
Glass and Aluminum
Some building codes contain a provision to omit the fire-resistive rating for a roof construction for some occupancy types when the roof is located more than ____ feet above the floor.
20
Type II-A (protected) requires that structural components have ___ hour fire resistance. This construction type is similar to Type I but with a lower requirement for fire resistance.
One
The use of ______ is the most common characteristic of of unprotected, noncombustible construction (Type II-B).
Unprotected Steel
Type ___ construction is frequently constructed with exterior walls of masonry, but from a technical standpoint, any noncombustible material with the required fire resistance can be used for the exterior walls.
III
Type III construction commonly uses nominal _” x _” joists for floor construction.
2” x 10”
A fundamental fire concern with Type __ 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.
III
Concealed spaces in Type III construction must contain appropriate _______.
Fire stops
Type __ is commonly known as heavy-timber or “mill” costruction.
IV
Two important distinctions between Type III and Type IV construction are:
-In Type IV construction the beams, columns, floors, and roofs are made of solid or laminated wood with dimensions GREATER than in Type III.
-Concealed spaces are NOT PERMITTED between structural components in Type IV.
Type __ construction is the only construction type that does not include A and B subdivisons. Instead, the designation 2HH is used.
IV
Type IV (heavy timber) construction requires minimum nominal dimensions of __” x __” for floor construction, which is thicker than needed in Types III ad V construction.
6” x 10”
In Type __ construction, all major structural components are permitted to be of combustible construction. The basic method of construction consists of using a wood frame to provide the primary structural support.
V
Many Type V structures are required to have a __ hour fire resistance for structural components.
One
The fundamental problem with Type V construction is the presence of ________.
Extensive void spaces.
*They provide avenues for extension of fire within a building.
In modern practice, wood-frame (Type V) buildings are most often constructed using a method known as _________ construction. This technique was introduced to the US in the 1830s and eliminated heavy posts and beams, instead making use of smaller studs, joists, and rafters.
Light-Frame
The IBC contains ten major occupancy classifications:
_____ Group A; _____ Group B; _____ Group E; _____ Group F; _____ Group H; _____ Group I; _____ Group M; _____ Group R; _____ Group S; _____ Group U
Assembly (A); Business (B); Educational (E); Factories (F); High Hazard (H); Institutional (I); Mercantile (M); Residential (R); Storage (S); Utility and Miscellaneous (U)
NFPA 5000 and NFPA 101 identify 12 major occupancy classifications:
Assembly; Educational; Day Care; Health Care; Ambulatory Health Care; Detention and Correctional; Residential; Residential Board and Care; Mercantile; Business; Industrial; Storage
Fuel Load (total quantity of combustible material in a compartment) contributes to the calculation of the ______ (the maximum amount of heat that can be released if all fuel is consumed).
Fire Load
The fire load will vary depending on the _______ of the fuel load.
Heat of Combustion
______ = Weight of combustibles X their ______ , expressed in pounds per square foot.
Fire Load ; Heat of Combustion
Buildings with combustible structural components (Types III, IV, V) have an inherently _____ fire load than noncombustible construction (Types I and II).
Greater
*because the structural framing materials contribute a significant amount of fuel to a fire.
A fire load may not directly translate into an equivalent _________.
Structural Load
*A Type IV warehouse containing iron radiators would have a high structural load but a light fire load.
*A toy store would have a moderate structural load but a high fire load because most toys are combustible with combustible packaging.
_______ describes several properties of a material, including: Combustibility, Thermal Conductivity, Chemical Composition, Density, and Demensions.
Fire Resistance
_____ indicates the ability of a structural assembly to maintain its load-bearing capacity and structural integrity under fire conditions.
Fire Resistance
The ________ can be evaluated quantitatively and expressed in time units including hours and fractions of hours. They can be incorporated into building codes and include minimum requirements for structural components such as Beams, Columns, Walls/partitions, Floor/ceiling assemblies, and roof/ceiling assemblies.
Fire Resistance Rating
________ is the most common method used to determine fire resistance.
Laboratory Testing
The standard test used to determine fire resistance is _________.
ASTM E-110. Aka NFPA 251
The primary points of failure for fire resistant laboratory testing are:
–Failure to support an applied load
–Temp increase on the unexposed side of wall, floor, and roof assemblies of ____F above ambient temps
–Passage of heat or flame through the assembly sufficient to ignite cotton waste
–Excess temp on steel members
250F
To provide more accurate and useful data, fire resistance ratings for test specimens are expressed in standard intervals (15min, 30min, 45min, 1hr, 1.5hr, 2hr, 3hr, 4hr) and are rounded ____ to the nearest interval.
Down
*An assembly that fails at 1 hour and 10min into a test is rated as ONE HOUR.
The standard E-119 test evaluates the ability of structural assemblies to carry a ______ and to act as a ______.
Structural Load ; Fire Barrier
