Bc Flashcards
(297 cards)
First digit in sub classification
Fire resistance rating in hours of exterior bearing walls
Second digit in sub classification
Fire resistance rating of structural frames or columns and girders that support loads of more than one floor
Third digit in sub classification
Fire resistance rating of the floor construction
Type I (fire resistive) construction
Noncombustible structural components.
Type I bearing walls, columns, and beams fire resistance rating
2-4 hours
Type I floor construction fire resistance rating
2 or 3 hours
Type I roof deck and construction supporting the roof fire resistance rating
1-2 hours
Type I partitions separating occupants fire resistance rating
As specified by local building codes
Type I interior partitions enclosing stairwells and corridors fire resistance rating
Specified by local code, usually 1 or 2 hours
Type II-A (protected)
Requires that structural components have a 1 hour fire resistance
Type II B (unprotected)
Allows structural components to remain unprotected. The use of unprotected steel is the most common characteristic of unprotected, noncombustible construction
Type III exterior protected/ ordinary
Frequently constructed with exterior walls of masonry, or any combustible material with the required fire resistance rating can be used.
Type III interior structural components that are permitted to be wholly or partially combustible include
-walls
-columns
-beams
-floors
-roofs
A fundamental fire concern with type III construction
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
Type III dimensions for floor joists
2”x10”
Type IV heavy timber or mill
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.
Type IV construction dimensions
Not less than 6”x10” for floors and beams, internal support columns are not less than 8”x8”
Type V wood frame
All major structural components are permitted to be of combustible construction. Many are required to have a 1-hour fire resistance rating for structural components
Fundamental problem with type V construction
Is the presence of extensive concealed voids
Nonreinforced masonry walls are usually limited to a maximum height of
6 stories
Most common method of supporting loads over openings in masonry walls
Lintels, followed by arches
If a single care hoistway is used access doors will be provided for rescue purposes and placed every
3 floors
When more than one hoistway is provided up to how many elevators are located in 1 hoistway
Four elevators
Fire doors are rated in increments of time from
20 minutes to 4 hours