A Comparison of the Fire Performance of

Prestressed Concrete Double T-beams

using Design Provisions and SAFIRThe

Station Nightclub Fire Evaluation

CE 808: Structural Fire Engineering

FridayMonday, AprilFebruary 814, 2008

Nickolas Hatinger

Megan Vivian

Table of Contents

I. Introduction .................................................................................................1

II. Literature Review ......................................................................................2

A. General ........................................................................................................2

B. Experimental Studies ...................................................................................2

C. Analytical Studies ........................................................................................6

III. Structural Models ......................................................................................8

IV. Design Codes ............................................................................................10

A. General ......................................................................................................10

B. American ....................................................................................................11

C. Canadian ....................................................................................................12

D. Eurocode ....................................................................................................13

V. SAFIR .......................................................................................................14

VI. Results/Discussion ....……………………………………………………16

VII. Conclusions ...............................................................................................17

VIII. Acknowledgements ..................................................................................18

IX. References ................................................................................................20

APPENDIX A: Sample Calculations .................................................................22

APPENDIX B: SAFIR Input Files .....................................................................40

I. Introduction

II. Literature Review

A. General

B. Experimental Studies

C. Analytical Studies 5

III. Structural Models

IV. Design Codes

A. General

B. American 10

C. Canadian 11

D. EuroCode

V. SAFIR

VI. Results

VII. Conclusions 2

VIII. Acknowledgements 3

IX. References 4

I. Introduction ............................................................................................................1

II. The Station Nightclub Fire ...................................................................................1

A. Structural and Material Features ............................................................................1

B. Ignition of Fire .........................................................................................................2

C. Fire Growth .............................................................................................................2

D. Fire Protection Features .........................................................................................3

E. Fire Service Response ..............................................................................................3

F. Structural Effects Due to Fire ..................................................................................3

G. Aftermath .................................................................................................................4

III. Lessons to be Learned ...........................................................................................4

A. NIST Investigations ..................................................................................................4

B. Human Behavior ......................................................................................................5

C. Recommendations ....................................................................................................5

IV. Conclusions .............................................................................................................6

V. References ................................................................................................................7

2

AbstractThe fire performance of two prestressed concrete double T-beams were assessed

using the tabulated data and simplified calculations under the American, Canadian, and

European design provisions, as well as with a performance-based approach, SAFIR. A

10DT24+2 and 12DT32+2 simply supported beams were selected as representative

beams typically incorporated into retail stores or parking structures, with spans of 40 and

50 ft., respectively. The design provisions coincided well with one another, but the

tabulated data fire ratings under the Canadian code proved to be slightly conservative.

Similarly, the SAFIR results were consistent with the design provisions for the

10DT24+2, but diverged slightly for the 12DT32+2 and were contributed to lack of

available temperature distributions for 90 minutes. Overall the prescriptive-based design

provisions provided reasonable results, but it is been suggested that American and

Canadian codes incorporate an advanced calculation method to promote accurate and

efficient fire safety designs.The purpose of this paper is to present a case study to

compare current structural fire safety design provisions in the United States, Canada, and

Europe to finite elements methods using SAFIR.The purpose of this paper is to present an

overview of The Station nightclub fire that led to death of 100 and injured 200 patrons on

February 20, 2003. The overview consists of a description the building’s features and

materials, fire ignition and growth, fire protection systems, response of emergency units,

and aftermath of the fire. In addition, it highlights the several simulations and tests

conducted by the NIST investigation to identify any negligence in safety of the nightclub

and further work that could be done to ensure safety among similar public structures. It

was conclude that fire severity or the event as whole could have been avoided if proper

building materials, sprinkler systems, and considerations of egress would have been

accounted for in the buildings design.

4

I. IntroductionIntroduction

II.

Fires are among earthquakes, hurricanes, floods, tornadoes, and blasts as one of

the most destructive forces subjected to a structure. In 2006, fire’s caused 3,245 civilian

fatalities, 16,400 civilian injuries, and $11,307,000,000 in property loss throughout the

United States, alone. A total of 524,000 structural fires contributed to $9.6 billion dollars

in property damage (Karter, 2007). The devastation and unpredictability of such

catastrophes is the reason why design provisions demand structures to meet minimal fire

safety requirements.

The philosophy of most design provisions around the world is to ensure life safety

and minimize property damage in the event of a fire. Commonly this is accomplished

through a prescriptive-based approach, which assigns structural elements fire ratings

through tabulated data derived from standard fire tests. Although widely practiced it is

limited in scope and restrictive in application. Therefore, countries such as New Zealand,

United Kingdom, Australia, Japan, Sweden, other European countries have moved

towards a performance-based methodology. The new method is intended to capture the

complexities of the event through the introduction of realistic fire scenarios (variation in

fuel loads and ventilation), loading regimes, and restraint, in attempt to develop a rational

and economic design alternative.

The purpose of this paper is to present a case study to compare the fire

performance of two precast prestressed concrete double T-beams through various

methods. The methods consist of design provisions from American, Canadian, and

European codes, as well as a finite-element methods using SAFIR to predict the

1

members’ fire response. The goals of the study are to illustrate the limitations of the

prescriptive-based approach and to promote the performance-based movement in an

attempt to accurately and efficiently predict the fire response of structural elements.

The following paper consists of seven main sections. First, is the introduction

discussed previously. Second, is the literature review, which identifies similar analytical

studies conducted in the past. In addition, a few experimental studies to explore how the

current provisions were established for the fire performance of prestressed concrete

beams. In the third section, a description of the structural models and loading are

presented. Overviews of the relevant codes are discussed in the fourth section. The

computer program SAFIR, used in the comparison, is detailed in the fifth section. Sixth,

are the results of the comparison. Finally, in the seventh section the relevant conclusions

are addressed.

In the Unites States alone, fires contribute to 3,245 civilian fire fatalities and

approximately $11,307,000,000 in property loss in 2006. Of this, about 524,000 fires

took place in structures; which accounted for $9.6 billion dollars in property damage

(Karter, 2007). A very small percentage of these structural fires typically occur in

nightclubs or similar venues, yet these occurrences lead to remarkably high numbers of

casualties.

One such structural fire, on the evening of February 20, 2003, at The Station

nightclub in Warwick, Rhode Island, took the lives of 100 civilians (FEMA, 2004). The

pyrotechnic display from the nightly entertainment created a spark causing ignition of

surrounding foam insulation and subsequently engulfed the entire building in flames.

Due to overcrowding and panicked egression of The Station, patrons were unable to

evacuate from the quick spreading fire and many perished that evening. Investigations

have been completed to determine any negligence in safety of the nightclub and further

work that can be done to ensure safety among similar public structures.

Literature Review

2

A. General

In the following discussion a series of experimental studies are reviewed to briefly

illustrate how the current prescriptive-based provisions were developed from standard

fire tests for prestressed concrete beams. In conclusion, the similarities among the

studies are highlighted and their limitations are identified. Subsequently, several

analytical studies are presented to provide similar research findings.

B. Experimental Studies

In general, most fire tests of precast prestressed concrete beams have been

performed to establish prescriptive-based codes under standard fire exposure. Most of

the ratings depend on concrete cover, cross-sectional area, reinforcement axis distance,

restraint, or insulation thickness. Many of these investigations were used not only to

establish design provisions, but also to validate models and identify prevalent failure

modes under elevated temperatures. The following are a series of fire test conducted to

establish current prescriptive-based design codes in the United States.

Gustaferro and Carlson (1962) compiled 50 standard fire tests on precast

prestressed concrete building components and conducted tests on a variety beams and

slabs to determine the factors which affect fire resistance. The tests were conducted from

1953 to 1961 collectively by the National Bureau of Standards, Underwriters

Laboratories, Portland Cement Association, and Fire Prevention Research Institute. An

assortment of span lengths, insulation thicknesses, aggregate types and cross sections of

members such as I-shaped, double-tee, and single-tee beams, as well as flat hollow-core,

solid, and stemmed floor assemblies were tested in accordance with ASTM E 119. The

factors which affected the fire resistance of the precast prestressed components were

3

concrete cover, degree of restraint, cross-sectional area, member geometry, aggregate

type, and concrete moisture content. The main factors which affected the strand

temperature were concrete cover, cross-sectional area, member shape, type of aggregate

and insulating protection. Although, all of the details of restraint were not provided for

each study, it proved to significantly increase the member’s fire resistance and typically

failed due to heat transmission. Conversely, the failure mode for unrestrained beams

primarily was due to prestressing strands exceeding their critical temperatures (850 to

950°F). Other key observations were that lightweight aggregates provided better fire

resistance than normal weight aggregates. The moisture content only became an issue

once 70% relative humidity was exceeded. Similarly, the vermiculite insulation has

proven to provide greater fire ratings as long as it remains bonded to the concrete.

Finally, a comparison of one studies results tabulated in Table 1 were deemed consistent

with the other tests, but was considered slightly conservative.

Table 1: Cover for various fire resistances (Gustaferro and Carlson 1962).

4

Selvaggio and Carlson (1964) performed a study on the influence of aggregate

type and load intensity on the fire resistance of twenty two prestressed concrete I-beams.

The beams were tested under standard fire tests with three-sided exposure and spanned

20 ft. Three different normal (dolomitic or siliceous) and lightweight (expanded shale’s)

aggregates were used. Two loading intensities were uniformly applied through different

live and dead load combinations. The results yielded, lightweight aggregates exhibited

the best fire performance and were remarkably similar. The dolomitic aggregates

exhibited the best fire performance of the normal weight aggregates, through delayed

heat transmission affects. Lightweight aggregate beams failed in a compressive manner,

while the normal weight aggregate beams failed in tension. When considering varying

load intensities, the heavier loading regime failed quicker with greater midspan

deflections. A few beams were restrained and revealed a 22% better fire performance

than simply supported beams. In addition, less thrust was observed in the expanded shale

aggregates compared to the normal weight aggregates.

Abrams and Gustaferro (1972) conducted fire endurance tests of four prestressed

concrete double T-beams with spray-applied insulation. Two different cross sections

were tested under the ASTM E119 standard fire with unrestrained support conditions. A

control specimen and two more beams with ½ and 1 in. of vermiculite acoustical plastic

insulation, consisted of one cross section. The other beam section used ½ in. mineral

fiber insulation. Their fire endurances were 1 hr. 2 min., 1 hr. 50 min., 3 hr. 6 min., and 2

hr. 28 min., respectively. Both types of insulation maintained adhesion throughout the

tests. A prescriptive based tabulated approach was suggested for 2 and 3 hr. ratings,

based on stem width, concrete cover, type and thickness of insulation.

5

The majority of the fire tests for the prestressed concrete beams were performed

in the 1960’s and 1970’s. Although these results are invaluable in determining many of

the factors affecting the members’ fire performance they are limited to standard fire

exposure and are not applicable to other potential fire scenarios. Other issues are raised

when considering the variability in size of the test specimens, because full-scale

specimens fail in different mechanisms than large specimens. In addition, although some

of the studies included restraint, it is only vaguely understood to improve the fire

resistance without any rational understanding to quantify such a scenario. Therefore,

crude tabulated fire ratings are assigned to a multitude of beams based on handful of fire

tests. The tabulated data limits a designer’s ability to push the envelope for new designs

and prevents new materials to be used without costly fire tests to assure fire ratings.

C. Analytical Studies

While reviewing the literature, no specific case studies were found that compared

fire ratings among different countries design provisions. However, several papers were

discovered in which finite-element methods were used to accurately estimate the fire

performance of prestressed concrete beams. The methods used in the studies are

examples of the types of procedures that are regularly used in a performance-based

methodology. The following are significant findings of each study.

Anderson and Laurisden (1999) undertook a comparison of prescribed fire ratings

to a series of calculations for prestressed concrete double T-beams roof assemblies. Four

participants (DTI, PJK, DTU, and FSD) used different calculation methods to determine

the fire ratings. Three used finite element programs (FEM), while the other performed

simplified calculation methods. The fire endurance calculations and tests were in

6

accordance with standard fire test method ISO 834. Three beams were tested and

modeled. The beams differed through their location of the prestressing steel from the

bottom flange (57, 73, and 83 mm). However, the second specimen temperature-time

curve was greater than ISO 834; therefore it was excluded from the results. Table 2

illustrates the results.

Table 2: Analysis method and fire test results (Anderson and Laurisden 1999).

All three beams failed initially to bond failure followed by shear fracture.

Spalling was observed in all three tests on the bottom surface of the slab between the

stems. The average fire resistance time calculated for type 1 and 3 beams were 36 and

6% greater than the actual fire tests. Although the moment calculations were similar for

7

DTI, DTU, and PJK, the shear and anchorage failure calculations were scattered. The

variations of the results are attributed to different material property reductions and bond

models incorporated in the different methods.

Franssen and Bruls (1997) performed a state-of-art analysis on a precast

prestressed concrete double-T beam to verify the results of a previous experiment under

the ISO 834 standard fire exposure. The manufacturer prescribed a 2 hr. fire rating for

the beams based solely on its ultimate bending capacity; however the test specimen failed

in 79 min. Therefore, the authors conducted a nonlinear thermo-mechanical analysis,

using a computer program called SAFIR, to validate the test. The bending capacity

analysis resulted in a fire rating of 91 min. and led to the conclusion that the beam failed

in a shear failure mode. The ultimate shear resistance was calculated using the method

proposed in Eurocode 2-Part 1-1. The study considered the contributions of the steel

stirrups, prestressing tendons, and concrete to the beams shear strength. As a result, the

calculations coincided very well with the tests at 80 min. However, the beam did not

satisfy code requirements; therefore the beam was modified in SAFIR to provide a fire

resistance for shear and bending moment of 135 and 130 min., respectively. A

subsequent fire test yielded a fire endurance of 144 min.

These studies proved that advanced calculation methods often used in

performance-based design procedures can yield accurate results. Although, these

methods are not always the best solution to a problem, in time they may minimize cost

associated with expensive fire tests for validation once a certain degree of confidence is

established. The structural models used for the comparison in this paper are discussed

next.

III. The Station Nightclub FireStructural Models

8

Figures 1 and 2 illustrate the two precast prestressed concrete double T-beams

selected arbitrarily to represent a typical floor/roof assembly used in shopping centers or

parking garages. A 12DT32+2 and 10DT24+2 spanning 50 and 40 ft., respectively, were

selected from the PCI Design Handbook (PCI, 2004). All of the relevant dimensions and

material properties are also shown in the figures 1 and 2 below. The beams are assumed

to be simply supported and loaded uniformly. A live load of 100 psf was used to

represent a typical live load for the first floor of a retail store (ASCE, 2005). The load

combinations and other specifics will be determined per code and will be discussed in the

next section.

Figure 1: Dimensions and properties for the 12DT32+2

9

10

Figure2: Dimensions and properties for the 10DT24+2

IV. Design Codes

A. General

Most countries throughout the world require structures to meet minimal fire safety

requirements. Typically, design provisions offer a hierarchy of design methods, such as

tabulated data, simplified calculations, and advanced methods. The hierarchy varies in

complexity of application, with the tabulated data being the easiest and the advanced

methods being the most arduous. Therefore, most design provisions are typically

established through either tabulated data or simplified calculations. However, in recent

years performance-based methods have come to the fore, offering more flexibility to

designers through a rational approach. Discussed below is an overview of U.S,

Canadian, and European design provisions used.

11

B. American

All concrete structures in the United States are designed in accordance with the

American Concrete Institute standards (ACI 318, 2005). However, this guide references

ACI 216 (2001) for the fire provisions of concrete structural members. The ACI

provisions provided for prestressed concrete beams are similar to the Precast/Prestressed

Concrete Institute Design Handbook (2004) and International Building Code (2006).

These codes offer tabulated data and simplified procedures to establish the fire

performance of a prestressed concrete beam. The ratings are valid for three-sided ASTM

E 119 standard fire exposure. The tabulated fire rating for the beams are based on

minimum concrete cover and depend on restraint, aggregate type, and either beam width

or cross-sectional area, depending on the table used. The restraint is categorized either

as restrained or unrestrained. The aggregate types are classified as either carbonate or

siliceous, lightweight or semi-lightweight, or all. Through these parameters a concrete

cover for fire ratings of 1, 1½, 2, 3, or 4 hours. Similarly, tabulated data is provided for

determining a fire rating based on the heat transmission failure criteria for slab and is

based on its thickness and type of aggregate.

Alternatively, ACI 216 provides guidelines for an analytical approach to

determine the fire resistance of prestressed concrete flexural members based on the

ASTM E119 standard fire condition. The method assumes that flexural tension governs

the design. The fire resistance is determined through curves based on heat transfer

principles to establish the temperatures in the prestressing steel and requires the type of

aggregate, moment intensity, minimum cover and reinforcement index. The temperatures

are used to asses the reduced strength and moment capacity of the section. The

12

remaining moment capacity must be greater than a load combination of 1.2D + 0.5L. It

should be noted that no advanced calculation methods, are currently available.

C. Canadian

The National Building Code of Canada (2004) governs concrete structures and

has very similar provisions as the Americans. The provisions provided for prestressed

concrete beams are prescriptive in nature. The method includes tabulated data to assess

the fire rating of 30, 45, 60, 90, 120, 180, or 240 minutes. The ratings are based on

concrete cover and depend on type of concrete and area of beam. The two types of

concrete are characterized as type S or N gravels, or type L for lightweight aggregates.

The dense aggregates is subdivided into 3 different intervals of area, while the

lightweight aggregates only apply once the area of the member has exceeded 970 mm2 .

The ratings are for unrestrained members and are applicable for either independent or

integral slabs or roof components. It is assumed that the unrestrained condition will

govern and will suffice for the restrained conditions. Subsequent provisions provide

multiplying factors when plaster or other fire proofing materials are present. Similarly,

tabulated data is provided for determining a fire rating based on the heat transmission

failure criteria for slab and is based on its thickness and type of concrete.

Alternatively, a Canadian design guide, CPCI (2007) offers a rational design

approach through simplified calculations using reduced material properties due to

elevated temperatures and is very similar to the Americans. However, it should be noted

that adequate temperature profiles were not available for 1, 3, and 4 hr ratings; therefore

the American temperatures were used. Furthermore, the load combination suggested was

D + L or service loads. Note, that no advanced methods were offered.

13

D. Eurocode

The majority of European countries design concrete structures in accordance with

the European Standards or better known as “Eurocode” (2004). All reinforced concrete

structures are governed by EN 1992-1-1 and the fire provisions are supplied in EN 1992-

1-2. The provisions offer tabulated data, simplified calculations and advanced methods.

The quickest method to crudely determine the fire resistance of a prestressed beam is

through the tabulated data. The tabulated prescriptive method gives fire ratings for 30,

60, 90, 120, 180, and 240 minutes for a three-sided fire exposure of prestressed beams.

The ratings are based on minimum beam width of the exposed flange, average axis

distance of tendon to the exposed surface, and web thickness for rectangular, tapered and

I-section beams. Two primary tables are supplied based on support conditions, either

simply or continuously supported. In addition, provisions suggest an increase in the axis

distance and beam widths for prestressing members. Another provision allows the

previous tables mentioned to be applicable for four-sided fire exposure, if minimum

beam area and height are met. Similarly, tabulated data is provided for determining a fire

rating based on the heat transmission failure criteria for slabs, which is based on its

thickness.

An alternative to the tabulated method is through simplified calculations similar

to the American and Canadian codes. It is incorporated similarly to actual design

procedure, except that reduced properties are applied for given temperature exposures.

However, it should be noted that adequate temperature profiles were not available for

tapered beams; therefore the American temperatures were used. The reduced properties,

such as cross-sectional area, yield strength of prestressing steel, and compressive strength

14

of various types of concrete are tabulated for different temperatures. In addition,

expressions are available for thermal and mechanical properties, as well as stress-strain

relations at elevated temperatures. The load combination suggested was D + 0.9L. The

advanced methods presented suggest requirements for a performance-based design for the

mechanical, thermal, and spalling of concrete, but also require validation of models.

V. SAFIR

SAFIR is a 3D thermal-mechanical analysis program used to assess the fire

performance of structural elements. The finite-element-method (FEM) incorporates

nonlinear temperature dependent properties and stress distributions. The twofold

procedure consists of first creating a thermal model. A thermal model is a 2D cross

section of the member discretized into nodes and elements of different materials, as

shown in figure 3. The model is exposed to a standard fire exposure to produce a The

model is exposed to a standard fire exposure to produce a temperature distribution at a

specific time as shown in figure 4. The second part of the

15

Figure 3: Discretization of model Figure 4: Temperature distributions

temperature distribution at a specific time as shown in figure 4. The second part of the

procedure consists of a structural analysis. Similarly, the structural model is discretized

into a series of nodes and elements to create a beam. The loading and support conditions

are established and the temperature distributions at given time increments are used to

assess the reduced properties at elevated temperatures. These reduced properties are used

in the structural analysis to determine the internal forces and deflections until collapse.

SAFIR was used to incorporate a performance-based approach to determine the

fire endurance of the prestressed concrete double T-beams. An analysis case was

performed for each design provision, since they incorporated different loading

16

combinations. The results of both the design provisions and SAFIR are presented next

section.

17

VI. Results/Discussion

Tables 3 and 4 show the fire performance of the 10DT24+2 and 12DT32+2

beams, respectively. The tables present the fire ratings per code in hours and the fire

endurance times using SAFIR in minutes. Please refer to appendix A and B for the

sample calculations and SAFIR input files, respectively. In addition, ambient

temperature calculations are provided.

Table 3: 10DT24+2 Fire resistance results

10DT24+2FIRE RESISTANCE (hr.)

Code: American Canadian EuropeanLoad Combination: 1.2D+.5L D+L D+0.9LTabulated: 1 1/2 1 1 1/2Simplified Calculations: 1 1 1SAFIR (min): 64 60 61

Table 3: 10DT24+2 Fire resistance results

12DT32+2FIRE RESISTANCE (hr.)

Code: American Canadian EuropeanLoad Combination: 1.2D+.5L D+L D+0.9LTabulated: 1 1/2 1 1 ½Simplified Calculations: 1 1 1SAFIR (min): 92 86 87

The results for both the tabulated and simplified calculations yield identical

results for both beams. However, minor discrepancies arise when comparing the

tabulated data for each code. The American and European codes are slightly

conservative with a 1 ½ hr fire rating for both beams compared to the 1 hr. rating

prescribed by the Canadian code. When considering the SAFIR results, they vary

slightly among the different codes, due to the various load combinations. Although these

results coincide well with the design provisions for the 10DT24+2, they tend to diverge

for the 12DT32+2. The 12DT32+2 results, show the simplified calculations

18

underestimatinge the fire ratings compared to SAFIR. This may not be the case if 90

min. temperature profiles are provided in the design provisions to accurately asses the fire

rating. In contrast, it may also be due to the assumption that the reduced prestressing

force is based on the temperature acquired at average strand centroid, rather then

developing this relationship for each individual strand. Another factor that may be

affecting the simplified calculations methods used. Overall the results prove to be

consistent and could arguably be claimed that the fire rating for the 10DT24+ and

12DT32+2, are 1 and 1 ½ hrs, respectively.

Figures 5 and 6 illustrate the midspan deflections based on SAFIR for the

10DT24+2 and 12DT32+2 beams, respectively. The deflections for both beams reflect

the loading combinations. They are greatest for the American code and lowest for the

Canadian code.

10DT24+2 Midspan Deflections

0

0.01

0.02

0.03

0.04

0.05

0 480 960 1440 1920 2400 2880 3360 3840

Time (sec)

Def

lect

ions

(m)

AmericanCanadianEuropean

Figure 5: Midspan deflections of a 10DT24+2 versus time

19

12DT32+2 Midspan Deflections

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 480 960 1440 1920 2400 2880 3360 3840 4320 4800 5280 5760

Time (sec)

Def

lect

ions

(m)

AmericanCanadianEuropean

Figure 6: Midspan deflections of a 12DT32+2 versus time

Conclusions

20

VII. Conclusions

The fire performance of two prestressed concrete double T-beams were assessed

using the tabulated data and simplified calculations for the American, Canadian, and

European design provisions, as well as with a performance-based approach using SAFIR.

Both design provisions yielded identical results for both beams. However, there were

minor differences in the American and European codes compared Canadian code.

Similarly, the SAFIR results were consistent with the design provisions for the

10DT24+2, but diverged slightly for the 12DT32+2. Therefore, it has been proven that

prescriptive-based design provisions can accurately assess the fire endurance of

prestressed concrete double T-beams. However, circumstances where limitations of

available temperature profiles or tabulated data exist, a performance-based approach

should be adopted to accurately and efficiently assess the fire performance of a member.

Therefore, it is suggested that the American and Canadian codes incorporate similar

advanced calculations methods to their arsenal of accepted analysis methods.

VIII. Acknowledgements

I would first like to thank Lansival Jean-Baptiste for his technical assistance and

mastery of SAFIR. Secondly, I would like thank my advisor and mentor for the

opportunity to help promote a new approach for design provisions in the United States.

21

IX. References

22

X.

1) Abrams, M.S. and Gustaferro, A.H. 1972. “Fire Endurance of Prestressed Concrete

Unit Coated with Spray-Applied Insulation”, Prestressed Concrete Institute, V. 17,

No. 1, pp. 82-103.

2) ACI 216. 2001. “Guide for Determining the Fire Endurance of Concrete Elements.”

American Concrete Institute, ACI. Detroit, MI, USA.

3) ACI 318. 2005. “Building code requirements for structural concrete and

Commentary.” American Concrete Institute, ACI. Detroit, MI, USA.

4) Anderson, N.E. and Laurisden, D.H. 1999. “TT-roof slabs.” Technical Report

X52650, Part 1. Danish Institute of Fire Technology, Denmark.

5) ASCE 7-05. 2005. “Minimum Design Loads for Buildings and Other Structures.”

American Society of Civil Engineers, ASCE. Reston, VA, USA.

6) BS EN 1992-1-1. 2004. “Eurocode 2: Design of concrete structures. General rules

and regulations for buildings British-Adopted European Standard.”

7) BS EN 1992-1-2. 2005. “Eurocode 2: Design of concrete structures. General rules –

Structural fire design rules for buildings British-Adopted European Standard.

8) CSA CAN3-D-2.10. 1995. “Code for the design of concrete structures for buildings.”

Canadian Standard Association, CSA. Rexdale, ON, Canada.

9) CPCI. 2007. “CPCI Design Handbook 4th edition.” Canadian Precast/Prestressed

Concrete Institute, CPCI. Ottawa, ON, Canada

10) Franssen, J.M. and Bruls, A. 1997. “Design and Tests of Prestressed Concrete

Beams”, Proceeding of the 5th International Symposium on Fire Safety Science,

IAFSS. Melbourne, Australia. pp. 1081-1092.

23

11) Franssen, J.M., Kodur, V.K.R. & Mason, J. 2002. “User’s Manual for SAFIR2004:

A Computer Program for Analysis of Structures Subjected to Fire.” Liege:

University of Liege, Belgium.

12) Gustaferro, A. H. and Carlson, C. C. 1962. “An Interpretation of Results of Fire

Tests of Prestressed Concrete Building Components.” Prestressed Concrete

Institute Journal. V. 7. pp. 14-43.

13) IBC 7, 2006. “Fire-resistance-rated construction.” International Building Code, IBC.

International Code Council, Falls Church, VA, USA.

14) Karter, M.J. 2007. “Fire Loss in the Untied States During 2006.” National Fire

Protection Association, NFPA. Quincy, MA, USA.

15) PCI MNL 120-04. 2004. “PCI Design Handbook 6th edition.” Precast and Prestressed

Concrete Institute, PCI. Chicago, IL, USA.

16) Selvaggio, S.L. and Carlson, C.C. 1964. “Fire Resistance of Prestressed Concrete Beams Study. Influence of Aggregate and Load Intensity”, Portland Concrete Institute, V. 6, No. 4, pp. 10-25.

24

APPENDIX A

Sample Calculations

25

APPENDIX B

XI. SAFIR Input FilesAcknowledgements

I would first like to thank Lansival Jean-Baptiste for his technical assistance and mastery

of SAFIR. Secondly, I would like thank my advisor and mentor for the opportunity to

help promote a new approach for design provisions in the United States.

26

XII. References

17) Abrams, M.S. and Gustaferro, A.H. 1972. “Fire Endurance of Prestressed Concrete

Unit Coated with Spray-Applied Insulation”, Prestressed Concrete Institute, V. 17,

No. 1, pp. 82-103.

18) ACI 216. 2001. “Guide for Determining the Fire Endurance of Concrete Elements.”

American Concrete Institute, ACI. Detroit, MI, USA.

19) Structural and Material Features

20) The Station, built in 1946, was a conventional wood frame structure with a small

basement that underwent numerous renovations since its initial construction. This

single-story building had an estimated area of 412 m2, with a main floor plan as

shown in Figure 1 (Grosshandler et al., 2005). As indicated in Figure 1, the

nightclub mostly consisted of the main bar, sunroom, and dance floor areas. Four

doors were located in these areas for exits. Windows were located on both sides of

the front entrance door.

21) The building’s interior contained combustibles such as flexible polyurethane foam

lining, ceiling tiles, wood paneling, carpet, gypsum board, and an industrial

polytechnic device (Madrzykowski, 2006).

22)

27

23)

24)

25)

26)

27)

28)

29)

30)

31)

32)

33)

34) Figure 1: Floor Plane of The Station nightclub (Grosshandler et al., 2005)

35) Ignition of Fire

36) Nightclub fires are most frequently caused by incendiary, electrical, cooking, or

smoking (FEMA, 2000). On the evening of February 20, the band performing on

the raised platform incorporated pyrotechnics into their show. These pyrotechnics

caused two ignition locations of the polyurethane foam that lined the walls and

ceiling of the platform and nearby alcove (shown in Figure 1).

37) Fire Growth

38) At first, those inside The Station mistook the ignition for part of the performance and

did not react as the fire spread. Yet within 30 seconds after the ignition time,

patrons of the nightclub had realized the seriousness of the situation at hand and the

rapid growth of the fire around the dance floor. Patrons began to evacuate the

28

building and the band stopped playing. The flames spread from the polyurethane

foam lining to the wood paneling and ceiling tiles and moved beyond the dance

floor into the remaining rooms and hallways. Within five minutes after ignition,

witnesses saw flames reaching out of the building.

39) Fire Protection Features

40) The Station, an unprotected wood frame structure, was not equipped with a sprinkler

system (not required for this building). Fire alarms and emergency strobe lights

were present and alerted patrons 41 seconds after ignition. Several fire

extinguishers were located in the nightclub, yet could not control the growing fire.

Within 90 seconds, a black smoke layer had formed and encompassed the area from

the ceiling to one foot below (Grosshandler et al., 2005).

41) With the lack of sprinkler system and quick formation of a heavy toxic smoke layer,

patrons began overflowing the doorways in a effort to evacuate. Exit signs were

installed above each exit doorway and emergency egress lighting were present.

Approximately, two thirds of the patrons flooded toward the main entrance door in

a large crowd, which caused many to fall in a stampede and prohibited them from

exiting. Therefore, successful egress was not possible and in less than 100 seconds,

patrons clogged the front door (Grosshandler et al., 2005).

42) Fire Service Response

43) The Rhode Island Emergency 911 Center received calls pertaining to The Station

nightclub fire 60 seconds after ignition. The response teams arrived at the site

about 5 minutes after ignition and recorded the first water use within 6 minutes.

These rescue workers were responsible for helping evacuate a few patrons that

29

were stuck in the front entrance. Three triage areas were stationed for injured

civilians and were transported for further medical assistance as needed

(Grosshandler et al., 2005).

44) Structural Effects Due to Fire

45) Despite the fire spread throughout the entire building, no structural effects due to the

fire were evident until about 25 minutes after ignition. At this time, a portion of the

main bars’ roof was showing fire and had partially collapsed. It was not until 45

minutes into the fire when a major portion of the main roof had collapsed. Fifteen

minutes later, the roof above the sunroom also collapsed. In the end, the nightclub

was virtually destroyed; just a few exterior walls remained standing near the front

entrance and kitchen areas (Grosshandler et al., 2005).

46) Aftermath

47) The Station nightclub fire led to largest life loss fire incident in the state’s history. A

total of 100 fatalities and 200 injuries were accounted for, out of the estimated 440

to 458 people in attendance that night (Grosshandler et al., 2005). The flames

destroyed the establishment and multiple cars in the adjacent parking lot. In lieu of

the circumstances, a full blown National Institute of Standards and Technology

(NIST) investigation was commissioned to determine any negligence in safety of

the nightclub and further work that could be done to ensure safety among similar

public structures. In 2006, the two owners of The Station were sentenced to 15

years in prison for pleading no contest to 100 counts of manslaughter (Winograd,

2006).

48) Lessons to be Learned

30

49) NIST Investigations

50) NIST investigated the effects of smoke and fire spread through computer simulation

and a fire test on a mock-up of the nightclub. Both the computer simulation and

fire test estimated that within 90 seconds of ignition the temperatures, heat fluxes

and combustion gasses would have led to severe incapacitation or death to those

immediately around the dance floor. Furthermore, NIST evaluated the impact that

sprinklers would have had on controlling the fire if present. In these tests, no

tenability criteria or other dangerous levels were exceeded in 200 seconds and

flashover was prevented (Grosshandler et al., 2005).

51) NIST investigators also created several egress simulations under different scenarios

using multiple computer programs. The minimal egress time was estimated to be

188 seconds when the main entrance was not clogged from the crowd crush.

However, a maximum egress time of 341 seconds was predicted when the stage

door and main entrance were assumed impassible in 30 and 90 seconds,

respectively (Grosshandler et al., 2005).

31

52) Human Behavior

53) Mixing the occurrence of fire with the pandemonium of The Station’s loud music,

flashing lights, low lighting levels, large crowds, alcohol, smoking, and

entertainment confirmed several basic tenets in fire safety. First, people often wait

for reinforcing clues before acting out. Secondly, occupants will attempt to exit

through the same door in which they entered (Tracey, 2004). This type of human

behavior caused a crowd crush when two thirds of the patrons, all at once,

attempted to exit the nightclub’s main door in which they entered. Figure 2

illustrates these tenets through locations of the bodies recovered after the fire was

extinguished.

54)

55) Figure 2: Locations of bodies recovered after the fire (Grosshandler et al., 2005)

56) Recommendations

57) As a result of The Station nightclub fire, NIST proposed numerous recommendations

for improving the safety of nightclubs. The following is a brief list of the most

32

significant recommendations (FP & FEJ, 2005):

58) Forbid materials which easily ignite and rapidly propagate flames

59) All nightclubs should have sprinkler systems

60) Increasing the factor of safety on egress times

61) Strengthening pyrotechnic device provisions

62) Conclusions

63) The Station Nightclub fire was a tragic event, but may have been avoided or its

severity lessened, if the following considerations were taken into account during

the design of the building. First and foremost, the polyurethane foam lining was an

extremely combustible material that should be forbidden in all structures to prevent

such ultrafast fires. Secondly, the NIST investigations estimated that if sprinkler

systems would have been incorporated into the structure, flashover and loss of life

or injury of innocent people could have been avoided all together. Finally, the

inability of the facility to properly evacuate the majority of the people through the

main entrance led to an increase in fatalities. The egress issue can be contributed to

the patron’s natural tendencies in a fire and the building’s poor design of the main

entrance which lead to a crowd crush in the narrow corridors.

64)

33

65) References

66) Delen, D. May 2004. “Nightclub fires I.” Canadian Consulting Engineering, V.

45,No. 3, pp. 6-7.

67) Federal Emergency Management Agency, FEMA. June 2004. "Nightclub Fires in

2000.” Topical Fire Research Series, V. 3, I – Issue 7. U.S. Fire

Administration/National Fire Data Center.

68) Grosshandler, W., Bryner, N., Madrzykowski, D., and Kuntz, K. June 2005.

“Report of the Technical Investigation of The Station Nightclub Fire.” NIST

NCSTAR 2: Vol. I. National Institute of Standards and Technology, NIST.

Gaithersburg, MD.

69) Karter, M.J. September 2007. “Fire Loss in the Untied States During 2006.”

National Fire Protection Association, NFPA. Quincy, MA.

70) Madrzykowski, D., Bryner, N., and Kerber, S.I. 2006. “The NIST Station Nightclub

Fire Investigation: Physical Simulation of the Fire.” National Institute of Standards

and Technology, NIST. Gaithersburg, MD.

71) Delen, D. and Hershfield, M. May 2004. “Nightclub fires I.” Canadian Consulting

Engineerings, Volume 45, pp. 67-68.

72) FP & FEJ. August 2005. “Action stations.” Fire prevention & Fire Engineers

Journal, pp. 34-36.

73) ACI 318. 2005. “Building code requirements for structural concrete and

Commentary.” American Concrete Institute, ACI. Detroit, MI, USA.

74) Anderson, N.E. and Laurisden, D.H. 1999. “TT-roof slabs.” Technical Report

X52650, Part 1. Danish Institute of Fire Technology, Denmark.

34

75) ASCE 7-05. 2005. “Minimum Design Loads for Buildings and Other Structures.”

American Society of Civil Engineers, ASCE. Reston, VA, USA.

76) BS EN 1992-1-1. 2004. “Eurocode 2: Design of concrete structures. General rules

and regulations for buildings British-Adopted European Standard.”

77) BS EN 1992-1-2. 2005. “Eurocode 2: Design of concrete structures. General rules –

Structural fire design rules for buildings British-Adopted European Standard.

78) CSA CAN3-D-2.10. 1995. “Code for the design of concrete structures for buildings.”

Canadian Standard Association, CSA. Rexdale, ON, Canada.

79) CPCI. 2007. “CPCI Design Handbook 4th edition.” Canadian Precast/Prestressed

Concrete Institute, CPCI. Ottawa, ON, Canada

80) Franssen, J.M. and Bruls, A. 1997. “Design and Tests of Prestressed Concrete

Beams”, Proceeding of the 5th International Symposium on Fire Safety Science,

IAFSS. Melbourne, Australia. pp. 1081-1092.

81) Franssen, J.M., Kodur, V.K.R. & Mason, J. 2002. “User’s Manual for SAFIR2004:

A Computer Program for Analysis of Structures Subjected to Fire.” Liege:

University of Liege, Belgium.

82) Gustaferro, A. H. and Carlson, C. C. 1962. “An Interpretation of Results of Fire

Tests of Prestressed Concrete Building Components.” Prestressed Concrete

Institute Journal. V. 7. pp. 14-43.

83) IBC 7, 2006. “Fire-resistance-rated construction.” International Building Code, IBC.

International Code Council, Falls Church, VA, USA.

84) Karter, M.J. 2007. “Fire Loss in the Untied States During 2006.” National Fire

Protection Association, NFPA. Quincy, MA, USA.

35

85) PCI MNL 120-04. 2004. “PCI Design Handbook 6th edition.” Precast and Prestressed

Concrete Institute, PCI. Chicago, IL, USA.

86) Selvaggio, S.L. and Carlson, C.C. 1964. “Fire Resistance of Prestressed Concrete Beams Study. Influence of Aggregate and Load Intensity”, Portland Concrete Institute, V. 6, No. 4, pp. 10-25.

36

87)

APPENDIX A

Sample Calculations

37

APPENDIX B

SAFIR Input Files

38