2 Structural Fire Resistance Building Classifications Flashcards
Fire resistance
The ability of structural assembly to maintain its load bank and structural integrity under fire conditions
Combustibility
Nature of the building structural system will impact the rate of fire growth
Fire resistance rating
Reading assigned to a material or an assembly after standardized testing by independent organization that identifies amount of time material or assembly of materials will resist a typical fire as measured on standard time temperature curve
In addition to classifying buildings by construction type building codes by
Their occupancy
In the case of walls petitions and ceilings fire resistance also means
The ability to act as a barrier to fire
True/false fire resistive construction is not prone to structural failure under fire conditions
True
Building codes will have requirements for fire resistance for these structural elements
Beams, columns, walls and partitions, floors and ceiling assemblies, roof and ceiling.
Building code will typically require the columns supporting floors and the fire was just a building the fire resistance rating of
Three hours
Walls enclosing a exit stairwell typically have a fire resistance rating of
One or two hours to protect the stairwell
There are three means by which the fire resistance of structural assemblies can be determined
Conducting standard fire resistance testing laboratory
Performing analytical calculations to determine the resistance to a standard fire test
Employing analytical structural fire engineering design methods based on exposure characteristics
The most commonly used method of determining fire resistance is
Laboratory test
The earliest known fire test on building materials were conducted in Germany
1884 to 1886
In the United States the first known fire test were conducted in
Denver Colorado 1890 with subsequent test in New York City 1896
NFPA 251
Standard method of tests for fire and durance building construction and materials
NFPA 251 is also designated as
ASTM E-119
What is the temperature curve in a fire resistance test furnace
1000° at five minutes, 1550° at 30 minutes 1700° at one hour, 1850° at two hours, 2000° at four hours, 2300° at eight hours
Because components are you there structural loadbearing or not the test results will be classified as
The bearing or non-non-bearing based on their intended use
The strengths and floor and ceiling assembly is affect the extent to which an assembly may
Rotate or expand exposed to temperatures affecting his ability to support a load
Structural fire systems test conducted they continue until
The specimen fails for the specified fire endurance for which the specimen being tested his reachEd
Primary points of failure for fire resistance test are
Failure to support and applied load, temperature increase on unexposed side of fall floor and roof of 250° above ambient temp
Passage of heat or flame through assembly enough to ignite cotton waste
Excessive temperature on steel numbers
Underwriters laboratory
Independent fire research testing lab that certifies equipment and materials
Failure point temperature on steel will depend on
How the steel is being used
Fire resistance rating for test specimen including fire doors and windows are in standard intervals of
15 minutes, 30 minutes, 45, one hour, 1.5 hour, two hours, three, four hour
Rated assemblies may perform differently in actual situations because
In the real world workmanship and materials encountered may vary
Fire stop
Solid materials used to prevent or limit vertical and horizontal spread of fire in hollow walls floors ceilings penetration of utility chases or fire rated assemblies
Fire rating test does not provide information on
Performance of object other than specified, evaluation to which assembly generates products of combustion, degree of limitation for the passage of smoke, fire behavior of joints between elements, measurement of flame spread over material surface, effect on fire endurance through openings in specified material
Joint systems for floor to wall and wall-to-wall connections are tested in accordance with
UL standard 2079 Standard for fire test of joint systems
Penetration of reading materials and building construction is a fire concerned because
It may not be properly fire stopped
Fire resistance directory
Directory that lists building assemblies that have been tested and given fire resistance rating’s published by UL
In 1997 American Society of civil engineers, and society of fire protection engineer’s, jointly developed standard calculation of fire resistance known as
ASCE/SFPE 29 Standard calculation methods for structural fire protection
Standard calculation methods for structural fire protection is limited to use wi
Structural steel, plain and reinforced concrete, timber and wood, concrete masonry, Clay masonry
The most commonly used method of satisfying building code requirements for structural fire resistance
NFPA 251 standard time temperature test
Noncombustible
In capable of supporting combustion under normal circumstances
Most commonly used test for determining combustibility
ASTM E 136 Standard test method for behavior of materials in a vertical tube furnace at 750°C
In the fields a fire protection in building code and code enforcement buildings are classified in what five groups
Type I, fire resistive Type ii, noncombustible for protected noncombustible Type III, exterior protected (masonry) Type iv, heavy timber Type v, wood frame
The classifications of building construction type are based on two attributes
Fire resistance and combustibility
NFPA 220
Standard on types of building construction
Further division of each type of building classification is done in which manner
Subclassification designated by three digit number code
The first digit in building classification subclassification means what
First digit refers to the fire resistance rating and hours of exterior bearing walls
What does the second did you mean for subclassifications of building type
Second digit refers to fire resistance rating of structural frames or columns and garters that support load more than one floor
What does the third digit mean in the subclassification of building types
Third digit indicates the fire resistance rating of the floor construction
What do building code to use to establish limits on the height an area of buildings
Use the type of construction and building occupancy in connection with sprinkler systems and separations
Generally type I building’s, bearing walls, columns, and beams are required to have a fire resistance rating of
2 to 4 hours depending on the code and construction classification
Type I floor construction is required to have fire resistance of
Two or three hours
Type i roof deck and construction supporting roof must have fire resistance of
One or two hours
Interior partitions and closing stairwells and hallways are required to be fire resistant in type I buildings for
Usually one or two hours
Partitions that separate occupancies or tenants and type I buildings and also required to be fire resistant when
depending on firecode
Some building codes contain a provision to omit the fire resistive rating for your roof construction and type one for some occupancies when the roof is
More than 20 feet above the floor
Type I. The fire resistive compartments provided by partitions and floors tend to
Slow the spread of fire through a building
Building code usually permit limited use of combustible materials type I construction typically permitted are
Roof covering, interior floor finish, interior wall finishing trim, doors and frames, window sashes and frames, platforms, nailing and furring, light transmitting plastics, restricted foam plastic
Two most common methods of constructing type I buildings are
Using reinforced concrete or protected steelframe
In a steel frame building, unprotected steel has no fire resistance. In order to be used in type I construction it must
Be protected by insulating material of varying thicknesses to achieve different ratings
Type ii construction can either be
Protected or unprotected
Type ii A structural components required to have what for the fire resistance rating
One hour
In type II B rating structural components are
Unprotected
Building code allows the use of combustible material in type II Similar to
Those and type I construction
Unprotected noncombustible building and collapse under fire conditions point at which unprotected members will fail depends on
Ceiling height, size of unprotect steel members, intensity and duration of fire
Protected noncombustible construction provides a degree of structural fire protection similar to
Type one depending on fire resistance provided
Interior structural members of type III construction may be
Protected or unprotected
Type III a construction is required to have a fire resistance rating for interior members of
One hour
Type III b construction has what requirements for interior structural member fire resistance
No fire resistance requirement
Type III construction is permitted to have with dimension smaller than type iv construction using typically what size beam joist
2 x 10”
Type iv construction the minimum dimensions for floor joist construction
6 x 10”
Primary fire concern and type III construction is
Void spaces between floor and ceiling joists and between studs and partition walls
Type IV construction is similar to type III construction in that
Exterior walls are masonry and structural members are combustible
Two important distinctions between type III and type IV construction
Type iv Structural beams are solid or laminated wood larger than type III
Concealed spaces are not permitted between structural members and type IV construction
Primary fire hazard IN type IV construction
Fuel load because of structural members in addition to building contents, old oils and residues in floor
Many type V structures are required to have what fire resistance for structural members
One hour usually five protecting structural members with gypsum
Fundamental fire hazard in type V
Extensive combustible void spaces
Light frame construction
Method for construction of wood frame buildings replace the use of heavy timber wood framing
Type v May have what restrictions because of exposure thread to adjacent structures
Maximum height restrictions
Light frame construction is really what
Stick built
Fire load
Amount of fuel within compartment expressed in pounds per square foot obtained by dividing amount of fuel by the floor area indicating maximum heat release. also known as fuel load
Ordinary combustible’s release how many BTUs per pound
7000 to 8000 BTU per pound
Occupancy with fire load of 10 pounds per square foot of ordinary construction would produce how many BTU per square foot
70,000 to 80,000 BTU per square foot
Structural load and fire load can be different because
Building contents would be fire load, and structural contents with the structural load
The occupancy classification assigns building occupancies into
Groups broadly similar fire risks
International building code, IBC, classifications of 10 major occupancies
Assembly, Group a Business, group B Educational, group E Factories, group F High hazard, group H Institutional, group I Mercantile, group M Residential, group R Storage, group S Utility and miscellaneous, group U
Occupancy types can be further divided into subgroups using
A single digit after the letter designation
For subgroups of residential occupancies
R1 primarily transient occupancy including hotels and motels
R2 occupancy is primarily permanent occupants more than two dwelling units apartments dormitories
R3. Permanent occupants not more than two dwelling units, adult faculties accommodations for five or fewer persons less than 24 hours
R4. Occupancy’s assisted-living 5 to 16 occupant
Five subgroups of assembly occupancies
A one, assembly occupancies fixed seating, theater concert
A two, assembly used for consuming food and drink, restaurant
A3. Used for worship recreation or amusement
A4 intended for viewing indoor sport events
A5. Outdoor activities such as bleachers grandstand stadium
IBC, total amount of subgroups within 10 major occupancy classification’s
26
NFPA 500
Building construction and safety code
NFPA 101
Life safety code
NFPA 5000, NFPA 101, 12 major occupancy classification’s
Assembly, educational, daycare, healthcare, ambulatory healthcare, detention center, residential, residential board and care, Mercantile, business, industrial, storage
To illuminate conflicts of mixed occupancies what is required
Fire resistive separations between various occupancy varying one through three hours
