Fire Performance of Concrete Structures - National Ready Mixed ...

spyfleaUrban and Civil

Nov 25, 2013 (3 years and 7 months ago)

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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)


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



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

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


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?


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


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.



Approximately 85 percent of fire deaths occur in homes. Fire strikes
approximately 86,500 apartments, 2,000 hotels and motels, and 740
dormitories annually.



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.



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”


Building and Fire Codes


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


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.



Active Fire Protection
: Fire protection systems that must be


activated to perform, such as sprinklers and smoke detectors.



Passive Fire Protection:
Fire resistance provided by elements


that inherently resist fire, such as non
-
combustible precast


concrete, concrete and masonry block.



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



Smoke detectors


Sprinklers


Duct detectors


Fire alarms





Passive Fire Protection



Fire rated walls


Fire rated floors


Fire rated separations


Role of Compartmentation


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


Fire Sprinklers
act to extinguish
a fire after a
specified
temperature is
achieved in the
upper gas layer

Role of Sprinklers

NFPA standards


NFPA 13
Standard for the Installation of Sprinkler
Systems



NFPA 13D
Standard for the Installation of Sprinkler
Systems in One
-

and Two
-
Family Dwellings and
Manufactured Homes



NFPA 13E
Recommended Practice for Fire Department
Operations in Properties Protected by Sprinkler and
Standpipe Systems



NFPA 13R
Standard for the Installation of Sprinkler
Systems in Residential Occupancies up to and Including
Four Stories in Height

Why sprinklers may fail


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


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



Speed of construction


Faster sales and re
-
sales


Lower operating costs


Lower insurance costs


Lower maintenance costs


Lower energy costs


Community acceptance




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



Fire safe non
-
combustible
construction


Does not burn


Does not produce smoke,
fumes or gases


Does not add fuel to the
fire


Provides minimum two
-
hour separation between
units


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


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


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


Fire Containment is
the last line of
defense should
sprinklers fail


To be effective, walls
and floors/ceilings
providing
compartmentation
should be of non
-
combustible
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, self
-
contained 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



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



Structural Design Load


Live Load + Dead Load +
FIRE



Goal of Fire Resistance Structures



Maintain structural stability


Reduce spread of fire


Experience total burnout without collapse

Concrete at elevated temperatures


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


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


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


1.
Qualification by Testing

2.
Calculated Fire Resistance

3.
Approval through Past Performance

4.
Engineered Analysis

Qualification by Testing


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


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



Insert video


Calculated Fire Resistance


The fire resistance associated with an element
or assembly shall be deemed acceptable
when established by the calculation
procedures in ACI 216



Plain reinforced concrete bearing and non
-
bearing 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

Semi
-
lightweight

2.7

3.3

3.8

4.6

5.4

Lightweight

2.5

3.1

3.6

4.4

5.1

Effect of Aggregate


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


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


Most fire deaths result not from
heat or burns but from inhaling
smoke and toxic gasses.



Gases produced in a fire include:
water, CO2, styrene, bromide,
and CO



Concrete does not produce toxic
gases when involved in a fire



Compartmentation with concrete
construction reduces the spread
of toxic gas or smoke.


Costs

FSCAC Cost Comparison Study


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




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


The building construction types, designed using the provisions of the
2003 International Building

Code, included:

Cost Study Results


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


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


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

708.3 Fire
-
resistance rating.
Fire partitions shall have a fire
-
resistance 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 fire
-
resistance 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


Example

How to adjust existing building code to reduce sprinkler
trade
-
offs

Take Action!


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


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


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


Include links (websites, names, brochure,
addresses, etc.)