Fire Performance of Concrete Structures

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Balanced Code
Provisions for
Residential Structures
Alliance for Concrete Codes
and Standards (ACCS)
Presented By:
Alliance for Concrete Codes and Standards
(ACCS)
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American Concrete Institute
American Concrete Pipe
Association
American Society of Concrete
Contractors
Architectural Precast
Association
Concrete Foundation
Association
Concrete Reinforcing Steel
Institute
Insulating Concrete Form
Association
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National Precast Concrete
Association
National Ready Mixed
Concrete Association
Post-Tensioning Institute
Portland Cement Association
Precast/Prestressed Concrete
Institute
Tilt-up Concrete Association
Wire Reinforcing Institute
Introduction
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Outline
Fire Loss
Building Codes
Balanced Design
Benefits of
Concrete in Fire
Costs Associated
with Concrete
Construction
Take Action!
Conclusions
Limitations to the Building Code
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Recent building code revisions have
reduced the use of passive fire protection
and provided an over-reliance on active
fire protection system s
 Sprinkler
trade-offs: the concept of
exchanging established passive fire
containment code provisions for active
protection
 Sprinkler system reliability unknown
What is fire safety?
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Fire safety is a component of Building
Safety. It concerns safety measures to
prevent the effects of fires and is the result
of proper use of fire protection measures.
Fire Loss in the United States
Fire loss
Fire Loss
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More than 4,000 people die in fires each year, with one death every
130 minutes. Fire kills more Americans than all natural disasters
combined.
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Approximately 85 percent of fire deaths occur in homes. Fire strikes
approximately 86,500 apartments, 2,000 hotels and motels, and 740
dormitories annually.
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Each year, fire departments are called to more than 1.7 million fires,
with a fire call received every 18 seconds. There are nearly 510,000
structure fires each year, with one occurring every 62 seconds.
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Fire causes more than $11 billion in property damage each year,
with about $9.5 billion resulting from structure fires. Half of the total
property damage occurs in residential properties.
Building and Fire Codes
Building and Fire Codes
are state or jurisdiction
specific
 Codes are the minimum
requirements – “the
basement”
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Building and Fire Codes
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What is a Building Code?
A building code is the minimum acceptable
standard used to regulate the design,
construction, and maintenance of buildings
for the purpose of protecting the health,
safety, and general welfare of the
building’s users.
Up To Date Building Codes
 Build
safe building
 Reduce deaths, injuries and property damage
 Preserve the built environment
 Reduce public and private disaster aid
 Maintain employment and businesses
 Level playing field for engineers, builders and
suppliers
 Provide economies of scale
 Maintain quality of life and property values
Building and Fire Codes
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Insert Building and Fire Code information
for location being presented
Balanced Design
Balanced design re-established the importance of passive design,
including compartmentalization, in combination with active design, to
deliver a more comprehensive fire protection system.
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Active Fire Protection: Fire protection systems that must be
activated to perform, such as sprinklers and smoke detectors.
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Passive Fire Protection: Fire resistance provided by elements
that inherently resist fire, such as non-combustible precast
concrete, concrete and masonry block.
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Balanced Design: A Combination of active and passive
design elements, as well as the concept of
compartmentalization, to greatly enhance fire protection at a
minimum cost.
Balanced Design
Total
Fire Protection
Active
Fire Protection
Passive
Fire Protection
Balanced Design
Active Fire Protection
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Smoke detectors
Sprinklers
Duct detectors
Fire alarms
Passive Fire Protection
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Fire rated walls
Fire rated floors
Fire rated separations
Role of Compartmentation
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Compartmentation
acts to contain fires
to a specified area
of the building or
structure
Without
compartmentation,
fire may spread
from one room or
building to a
another
Role of Sprinklers
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Fire Sprinklers
act to extinguish
a fire after a
specified
temperature is
achieved in the
upper gas layer
Role of Sprinklers
NFPA standards
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NFPA 13 Standard for the Installation of Sprinkler
Systems
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NFPA 13D Standard for the Installation of Sprinkler
Systems in One- and Two-Family Dwellings and
Manufactured Homes
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NFPA 13E Recommended Practice for Fire Department
Operations in Properties Protected by Sprinkler and
Standpipe Systems
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NFPA 13R Standard for the Installation of Sprinkler
Systems in Residential Occupancies up to and Including
Four Stories in Height
Why sprinklers may fail
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Natural Events (earthquake, tornado, etc.)
Terrorist Events
Inadequate water pressure
Human Error
Lack of maintenance
Installation Error
Wrong sprinkler for occupancy/fire
Coverage Issues
Building under construction
Other
Options for Non-combustible
construction
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cast-in-place
hollow-core precast
concrete floors,
ceilings, and roofs
cast-in place
concrete
precast concrete
Concrete masonry
walls
Advantages of Non-combustible
construction for owners/developers
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Speed of construction
Faster sales and re-sales
Lower operating costs
Lower insurance costs
Lower maintenance costs
Lower energy costs
Community acceptance
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Lowest life-cycle costs
Higher appreciation
Attracts quality oriented
occupants
Appeals to investors
Proven performance
Resistant to seismic and
high wind damage
Advantages of Non-combustible
construction for occupants
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Fire safe non-combustible
construction
Does not burn
Does not produce smoke,
fumes or gases
Does not add fuel to the
fire
Provides minimum twohour separation between
units
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Serves passively for the
life of the building
Lower insurance costs
Needs no testing or
inspection
No bouncy or creaky
floors
Superior acoustic
qualities
Security for occupants
and contents
Advantages of Non-combustible
construction for communities
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Lower risk and exposure for
the fire service
More efficient use of fire
services
Construction does not add fuel
to the fire
Fire is contained
Adjacent units are protected
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Structural collapse is unlikely
Provides quality community
asset for many decades
Community recognized for its
fire safe construction
Provides a stable tax base for
the community
Attracts long term investors to
the community.
Fire Containment
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Fire Containment is
the last line of
defense should
sprinklers fail
To be effective, walls
and floors/ceilings
providing
compartmentation
should be of noncombustible
construction with at
least 2 hours of fire
resistance.
Firefighter Safety
 A concrete structure can utilize fire
rated concrete walls to create
compartmentation. The combination
of concrete columns, beams, flooring,
ceiling and wall elements breaks up
each level’s space into smaller, selfcontained modules that minimize the
chance of fire spreading to adjacent
units
 The containment of fire in these small
spaces makes entry safer for the
firefighter and maintains that building
collapse is rare
Fire Resistance
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Concrete has history of good performance in fire
Concrete is non-combustible and has low thermal
conductivity
Concrete maintains cool inner core during many fires
which maintains load
Fire Resistance
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Structural Design Load
 Live Load + Dead Load + FIRE
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Goal of Fire Resistance Structures
 Maintain structural stability
 Reduce spread of fire
 Experience total burnout without collapse
Concrete at elevated temperatures
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250 – 420 °C: Some spalling
occurs
300 °C: Loss of strength
begins
550 – 600 °C: Cement based
materials experience creep
and lose their load bearing
capacity
600 °C: Greater than this
temperature, concrete is not
functioning at its full structural
capacity
900 °C: Temperature of Flame
Fire Resistance
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The term "fire-resistance" designates the ability of a
laboratory-constructed assembly to contain a fire in a
carefully controlled test setting for a specified period of
time.
Harmathy’s Rules of Fire Endurance
ACI 216
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ACI 216.1-97: Standard Method for Determining
Fire Resistance of Concrete and Masonry
Construction Assemblies
ACI 216
Determines Fire Resistance through one of four
methods
Qualification by Testing
2. Calculated Fire Resistance
3. Approval through Past Performance
4. Engineered Analysis
1.
Qualification by Testing
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The most common test method for determining
fire resistance in the United States is the ASTM
Standard E 119 Test Methods for Fire Tests of
Building Construction and Materials.
ASTM E119
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Three End Points to fire test:
1. Ignition of cotton waste
supported on the member
surface that is away from the
surface directly exposed to
fire.
2. A temperature increase of 325
F at any point or 250 F on
average on the unexposed
surface (the heat-transmission
end point).
3. Inability to carry the applied
design load (i.e., structural
collapse).
ASTM E119
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Insert video
Calculated Fire Resistance
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The fire resistance associated with an element
or assembly shall be deemed acceptable
when established by the calculation
procedures in ACI 216
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Plain reinforced concrete bearing and nonbearing walls, floors and roof slabs shall
conform with the minimum thickness provided
in ACI 216 Table 2.1
Calculated Fire Resistance
ACI 216.1-97 Table 2.1. Fire Resistance of singular layer concrete walls, floors, and roofs
Aggregate
Type
Minimum equivalent thickness for fire
resistance rating, in.
1 hr
1 ½ hr
2 hr
3 hr
4 hr
Siliceous
3.5
4.3
5.0
6.2
7.0
Carbonate
3.2
4.0
4.6
5.7
6.6
Semilightweight
2.7
3.3
3.8
4.6
5.4
Lightweight
2.5
3.1
3.6
4.4
5.1
Effect of Aggregate
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The choice of aggregate directly impacts the
performance of concrete during a fire
Wood Fire
Fire Resistance of Wood is significantly lower than that of concrete
Fire Resistance
Strength at elevated temperatures
Fire Spread
 Concrete will not ignite.
The fire’s spread is
slowed and its damage
is minimized.
 This ability to resist fire
creates more time for
detection, evacuation
and suppression—the
three key ingredients for
minimizing damage and
injury during a fire.
Flame Spread
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Concrete will limit flame spread
Interior Finish
The majority of fire deaths in a residential home is due to
toxic products of combustion from interior finish
Toxicity
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Most fire deaths result not from
heat or burns but from inhaling
smoke and toxic gasses.
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Gases produced in a fire include:
water, CO2, styrene, bromide,
and CO
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Concrete does not produce toxic
gases when involved in a fire
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Compartmentation with concrete
construction reduces the spread
of toxic gas or smoke.
Costs
FSCAC Cost Comparison Study
The building construction types, designed using the provisions of the
2003 International Building Code, included:
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Conventional wood framing
with wood floor system (Type
V-B Construction)
Conventional wood framing
with wood floor system (Type
V-A Construction)
Light gauge steel framing with
cast-in-place concrete floor
system on metal form deck
Insulated concrete form
exterior walls with interior
bearing walls constructed of
concrete masonry units and
precast concrete floor system
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Load bearing concrete
masonry with precast
concrete floor system
Load-bearing concrete
masonry with cast-inplace
concrete floor system
Precast concrete walls with
precast concrete Floor system
Insulated concrete form walls
with precast concrete floor
system
Insulated concrete form walls
with cast-inplace concrete
floor system
Cost Study Results
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The study provides the relative cost as a comparison to wood frame as a
baseline of 100%, indicating increases or decreases relative to the baseline.
Cost percentages shown below are examples of those provided by the
complete study.
Insurance Benefit
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With increased emphasis on risk avoidance in the insurance
industry, property insurers and risk insurance managers have
noticed the fire-resisting advantages offered by non-combustible
construction
Source: Concrete & Masonry Industry Firesafety Committee’s Fire Protection Planning Report No. 9
Ensure safer Buildings through
code adoption
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Adopt a model building code which supports the
concept of balanced design
 Ensure
building code does not depend fully on active
fire protection systems or incorporate the idea of
“sprinkler trade-offs”
 Support amendments to the code which allows for
adequate passive fire protection design
 Consider using concrete in the building design to
provide excellent fire resistant construction
Example
How to adjust existing building code to reduce sprinkler
trade-offs
708.3 Fire-resistance rating. Fire partitions shall have a fireresistance rating of not less than 1 hour.
Exceptions:
1. Corridor walls as permitted by Table 1017.1.
2. Dwelling unit and sleeping unit separations in buildings of
Types
IIB, IIIB and VB construction shall have fireresistance ratings of not less than 1 /2 hour in buildings
equipped throughout with an automatic sprinkler system in
accordance with Section rated
corridor as required by
Section 903.3.1.1
Take Action!
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Find out which (if any!) building
code your state or jurisdiction
currently enforces or adopts
Research whether the code
adequately addresses the ideas
incorporated in the balanced design
approach
Contact your building code official
or state representative and submit
your concerns
Work with local groups for adoption
of strict amendments ensuring
balanced design and participate in
the development of the model code
process
Educate others on the benefits of
concrete construction, passive fire
protection and balanced design.
Conclusions
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Adequate building codes with a balanced design
approach can provide safe buildings for
occupants, owners and fire safety officials
Concrete is a non-combustible building material
that will
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Limit flame spread
Reduce costs
Not produce toxic gases during fire
Provide high fire resistance
Ensure fire containment
Construct at similar costs to other construction methods
Resources
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Include links (websites, names, brochure,
addresses, etc.)
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