2. CODE ANALYSIS
Decision on Construction type based on a give
occupancy
Allowable building area and height per construction type
Economics and Utility – least costly and complicated
construction allowed by code
Provide sufficient area for intended use
Speculative for profit buildings
Sustainability
GOAL – maximize allowable height and area given a
construction type
3. Building elements
Columns, floor/ceiling systems, interior walls, and
vertical shafts
Structural elements
Support the weight of the building
4. Fire resistance principle based on desire to limit
spread of fire from:
One building to another
One area to another
One floor to another
5. Codes define construction types by defining the
kinds of materials to be used for building and
construction elements
Establishes the minimum hourly fire rating of
building elements
Materials categorized as noncombustible, limited
combustible, and combustible
6. Fire rating – Hourly fire endurance rating not
fireproof
Non combustible – ‘material of which no part will
ignite and burn when subjected to fire’ – 1997 UBC
Masonry, concrete, steel
Combustible – wood and plastics
7. A protected – additional covering must be added
to add the fire resistance of the material
B unprotected – nothing added
8.
9. Required ratings for specific structural elements may
vary
Construction types divided into subcategories
Protected (A) – structural components must have
added fire protective enclosure that adds to the fire
resistance of the material
Unprotected (B) – no additional treatment or
covering required to be added to the structural
components
10. Every building must have a construction type
classification
If even one of the construction type criteria is failed
to be met, it then falls into the next least resistive
category
Interior project modifications must make sure that
any modifications to the building or structural
elements does not change their construction type
requirements
11. Use of performance codes may be allowed
Older buildings where construction type is not easily
determined
Structural material fire ratings impossible to classify
Matching existing construction will result in below
standard requirements
Requires ‘appropriate’ fire resistance for the
structural member, potential exposure to fire, height
and use of the building
12. Hour fire rating represents length of time material or
assembly must resist fire
How easily they ignite
How long they burn once ignited
How quickly flames spread
How much heat the material generates
Higher hour rating indicates noncombustible materials
are required
Low hour ratings indicates that fire-resistant or limited
combustible materials are allowed (amount may be
limited)
13. Noncombustible materials – will not ignite, burn,
support combustion, or release flammable vapors
when subject to fire or heat
ASTME136 Standard Test Method for Behavior of
Materials in a Vertical Tube Furnace at 750
degrees Celsius
Steel
Iron
Concrete
Masonry
14. Combustible materials – will ignite and continue to
burn once flame source is removed
Wood
Can be chemically treated to achieve some fire
resistance
Fire-retardant treated wood FRTW
Fire treated wood can be used in most rated walls
Can also be used as finish material – trims
15. Fire resistant if cross section is large enough –
Heavy timber
Builds a layer of char during a fire that helps
protect the rest of the timber
Columns 8x8”
Beams 6x10”
16. Fire resistant and limited combustible materials can
be used in combination with other materials to
create rated assemblies
Wood studs with gypsum board on both sides – 1
hour rated wall
17. TYPE I AND II CONSTRUCTION
Steel and concrete – considered noncombustible
Difference between types is the required fire rating of the structural
elements
High rise and large buildings
Type IA construction – highest level of fire-resistance-rated
construction – passive protection for all elements of the structure
Type IB – permits reduction of 1 hr. in structural frame and ½ hr. in
roof construction
Type IIA – allows active or passive protection on all members
Type IIB – allows unprotected noncombustible building elements
Combustible materials of limited quantity and used in conditions
where they will not contribute or compromise the resistance of
structural members
18. TYPE III CONSTRUCTION
Mixed combustible and noncombustible elements
Exterior is non combustible – masonry
Interior structural and roof may be wood
Small office building or urban buildings adjacent to each other
Type III buildings have mix of combustible and noncombustible
construction – construction type resulted from prevention of
fires between buildings by igniting the exterior walls – interior
allowed to be combustible
19. TYPE IV CONSTRUCTION
Heavy timber
No concealed spaces such as soffits, plenums or suspended
ceilings
Type IV address safety in manufacturing and storage buildings
– exterior walls of noncombustible construction and interior
structure and floors made up of heavy timber members
No concealed spaces in building elements
Floor framing minimum nominal thickness 3” and held away
from exterior wall and must have fire blocking
20. TYPE V CONSTRUCTION
Most combustible
All wood
Exterior may be brick veneer, siding or stucco
Typically small buildings – residential house,
dentist’s office, convenience store
Allows any material permitted by codes
Fire resistance is provided by adding fire resistant
materials to encapsulate the structural members
21. EXAMPLE
You are asked to design an office in a floor of an
existing building
Before deciding on the rating and materials of
interior walls and ceilings. Identify building
construction type
Is the frame wood, steel, concrete block or other
masonry?
What are the exterior walls?
Are the floors wood or concrete?
22. It is possible to have two construction types in the same
building
Construction types must be separated from each other
Vertical separation – Fire Wall
Party Wall is similar – shared lot line between two parcels of
land
Must extend from foundation through the roof to the parapet
Must remain stable even if one side of the wall collapses during fire
Horizontal separation – horizontal assembly
Must extend over the entire floor to the exterior or another
vertical fire wall
23. Stricter construction types is linked to large
occupancies, thus allowing more evacuation time
Assembly
Hazardous
Institutional
24. Sustainability requirements
Steel and concrete – typical structural material
Steel often made of 100% recyclable content and
recyclable afterwards
Concrete can be made up of recycled content and
recyclable afterwards
Wood – renewable material
Must come from sustainably managed forests
25. Height and Area of a building limited by
Occupancy type
Construction type
Whether or not building is sprinklered
Whether there are adjacent buildings