Flashcards in Ch. 2 Structural Fire Resist. and Bldg Class. Deck (45):
What will impact rate of fire growth?
Combustible nature of bldgs structural system
Determines likelihood of structural collapse under fire conditions.
Classifications of buildings based on:
Fire resistance is a function of the properties of all materials used, including (5)
In the case of ________, ________ and ________, fire resistivity also means the ability to act as a BARRIER to fire.
In addition to classifying buildings by construction type, building codes classify buildings by:
MOST COMMONLY used method for determine fire resistance ratings is: (aka Most Often)
(other 2: analytical CALCULATIONS and analytical structural fire engineering DESIGN METHODS)
Fire resistance of structural components can be evaluated ________ and is known as the fire resistance rating. Expressed in _______ and _________.
Hours and FRACTIONS of hours
Standard method of tests of fire endurance of bldg. constr. and materials
NFPA 251 or ASTM E-119
Could be too severe or not severe enough
*UL test furnace 14x17 ft. for beams, floor and roof assemblies*
Time scale for standard fire test: 5 min, 30 min and 1 hr
5 min = 1,000F.
30 min = 1,550F.
1 hr = 1,700F.
Structural specimen is tested, test is continued until _______ OR ________________.
The specified fire endurance is reached
Primary points of failure for (furnace) test: (4)
Failure to support applied load.
Temperature increase on UNEXPOSED side of WALL, FLOOR or ROOF, 250F above ambient.
Passage of heat/flame through assembly to ignite cotton waste.
Excess temperature in steel members.
*certain walls/partitions subjected to hose stream*
In actual situations, may perform satisfactorily for longer or shorter periods of time. Variation due to:
Differences in workmanship AND
Materials encountered in the real world
Standard test fire assumes:
ENDLESS fuel supply.
Standard test evaluates the ability of structural assemblies to _______ and to ______.
-carry a structural load.
-act as a fire barrier.
*not for smoke, assemblies other than those tested, joints*
(Joints UL 2079)
Fire testing organizations
Cal Berkeley, Forest Products Lab.
Armstrong cork Co.
National Gypsum Co.
ASCE/SFPE 29 is standard for _______.
Calculations of fire resistance (mathematical)
Std method for behavior of materials VERTICAL TUBE at 750F
*most common test for determining COMBUSTIBILITY*
Codes make use of _______ but do not make use of ____.
What does Bldg Constr and HOT call type/class III?
BC = EXTERIOR PROTECTED (masonry)
HOT = ordinary (brick and wood joist)
Most significant characteristic of bldg construction:
How it behaves under fire conditions
*bldgs CLASSIFIED how they behave under fire conditions*
In NFPA 220, each classification is designated by a ______ code. The first digit refers to _____. The second digit refers to ____. The third digit refers to ____.
First-exterior bearing walls
Second-structural frames, columns and girders (more than 1 floor)
Type I required fire resistance
- walls, columns and beams =
- floors =
- roof deck/supports =
- interior partitions =
wcb = 2-4 hrs
floors = 2-3 hrs
roof deck/supports = 1-2 hrs
interior partitions/stairwells/corridors = 1-2 hrs
Type I types of construction
I-A = 4.4.2
I-B = 3.3.2
2 most common methods of constructing Type I
-protected steel frame
2 attributes of concrete that make it fundamentally fire-resistive
Inherently noncombustible material
Good thermal insulating properties
Most common characteristic of unprotected, noncombustible construction
Use of unprotected steel
Type II with degree of fire resistance referred to:
-protected noncombustible construction
2 subclassifications of Type II: Type II-A and II-B:
II-A = 1 hr fire resistance for STRUCTURAL components.
II-B = unprotected structural STRUCTURAL components.
Point at which unprotected members fail depends on: (3)
-size of members
-intensity/duration of fire
Frequently constructed with exterior walls of masonry but can be ________________.
Any noncombustible material with required fire resistance
Type III has III-A and III-B
III-A = 1 hr fire-resistive for INTERIOR MEMBERS (2.1.1), fire rating for structural components
III-B = no fire resistance for INTERIOR MEMBERS (2.0.0), unprotected steel sometime used
When III-A has to have fire rating, most common are:
-plaster in old
-gypsum board in new
Fundamental fire concern with Type III construction is:
Combustible concealed spaces
-between floor and ceiling joists
-between stud and partition walls
* essential that concealed spaces to be firestopped.*
2 distinctions between Type III and Type IV
Type IV beams, columns, floors and roofs made of SOLID wood with dimensions GREATER than Type III
Concealed spaces are not permitted between structural members in Type IV
Primary fire hazard with Type IV
Massive amount of fuel by large structural members
-in addition to building contents
Many Type V structures required to have ______ fire resistance for ________. Typically accomplished by_____ or ______.
-plaster OR fire-rated gypsum board
In modern practice, wood frame buildings most often constructed using ___________.
"common currency of small residential and commercial buildings in North America today"
______ is the product of the weight of the combustibles multiplied by their heat of combustion. Also used as a measure of potential heat release.
Fire Load = also known as Fuel Load
Expressed in pounds per square foot
A fire load does not translate into an equivalent ________.
Classifying buildings according to ______ facilitates the administration of a code.
IBC residential occupancies (4)
R2-permanent MORE than 2 units
R3-permanent LESS than 2 units (adult/child 5 or fewer for 24 hrs)
R4-assisted-living, 5-16 occupants
IBC Assembly occupancies (5)
A3-worship, recreation, amusement
A5-outdoor-bleachers, grandstands, stadiums
IBC/NFPA common classes (ABEMRS)
*IBC-FHIU and NFPA-DHADRI*