S. Shyam Sunder, Lead Investigator

Building and Fire Research Laboratory

National Institute of Standards and Technology

U.S. Department of Commerce

sunder@nist.gov

NIST Response to the World Trade Center Disas

World Trade Center Investigation Sta

and First-Person Data Collection

September 17, 2003
Goals

• To investigate the building construction, the materials used, an

technical conditions that contributed to the outcome of the WorCenter disaster

• To serve as the basis for national benefits:

• Improvements in the way buildings are designed, construc

maintained, and used

• Improved tools, guidance for industry and safety officials• Revisions to codes, standards, and practices• Improved public safety
Objectives

• Determine:

• why and how the WTC Towers collapsed following t

impact of the aircraft, and

• why and how the 47-story WTC 7 collapsed

• Determine why the injuries and fatalities were so low or 

depending on location, including technical aspects of firprotection, occupant behavior, evacuation, and emer

response

• Determine what procedures and practices were used 

design, construction, operation, and maintenance of the buildings

• Identify, as specifically as possible, national building an

codes, standards, and practices that warrant revision
NIST WTC Investigation Proje

Analysis

of Steel Structural

Collapse

Evac

Baseline

Performance

& Impact

Damage

Analysis of

Codes and

Practices

Fire Service

Response

Active Fire

Suppression

Thermal and

Tenability

Environment

Public InputsDocumentsVideo/ PhotographicRecordsOral History DataEmergency ResponseRecordsRecovered StructuralSteelBPATRecommendationsGovernment,Industry,Professional,Academic InputsPublic Inputs
WTC Investigation Status

• Halfway into 24-month investigation; good progress on all proje• $16 million investigation; $5.5 million planned for contracts; $5

awarded or in review/negotiation process for 15 of 16 contracts

• Drawing on top-notch talent from NIST, outside experts, and co• Large amounts of data and information received; working hard 

access missing crucial information; summary status available http://wtc.nist.gov

• Two progress reports issued (December 2002 and May 2003); 

progress report scheduled for December 2003

• Extensive briefings at two meetings of the National Constructio

Team Advisory Committee (April 2003 and August 2003)
WTC Investigation Schedule

0 6 12 18 24 

Development of Plan

Discovery & Collection of Data

Review of Data & Formulation of

Technical Approach

Modeling, Testing & Field Data

Collection

Analysis of Results & Development

of Findings, Conclusions &

Recommendations

Development of Draft Report

2/1/02 8/1/02 2/1/03 8/1/03 2/1/04 

8/21/03

8/21/02 

Technica

Work

Complet

6/30/04
Selection of External Experts and Contr

• Process nearing completion

• Solicitations issued: 16 (1 replaced w• Awards made: 6 contracts

9 experts (3 solicitations

• Under review 2 contracts (anticipate by • Under negotiation: 3 contracts (anticipate by • Open solicitations: 1 contracts (anticipate by 

• Four others hired as expert consultants

• V. Junker; K. Malley, V. Dunn, J. Hodgens

• Excellent group of contractors and experts to augment NIS

house capabilities
11 2 Analysis of Aircraft Impacts into the WTC Towers Anticipate 9/22/03 T

T

T

TT

T

SBVULNRLNGWVHDG

Open; closes9/26/03

16 4 Analysis of Smoke Management Systems, WTC 1, 2, and 715 4 Analysis of Active Fire Alarm Systems, WTC 1, 2, and 7 Anticipate 10/15/03

Structural Response of WTC Towers to Fire With/Without Impact Anticipate 10/15/03Damage

14 613 6 Development of WTC 7 Structural Models and Collapse Hypotheses Anticipate 9/22/0312 4 Analysis of Sprinklers, Standpipe, Pre-Connected Hoses in WTC 1, 2, 7 Anticipate 9/22/03

Awarded 6/16/03,6/23-25/03, 7/3/03

Outside Experts for Baseline Structural Performance, Impact Analysis,Structural Response to Fire, Collapse Initiation and ProbabilisticAssessment of the WTC Investigation

10 2, 5, 6

Awarded 7/10/03Modified 8/22/03

9 6 Fire Endurance Testing of the WTC Floor System8 7 World Trade Center Investigation First Person Accounts of Egress Awarded 4/15/037 1 Analysis of Building and Fire Codes and Practices Awarded 7/25/03

Development of Structural Databases and Baseline Models for the Awarded 2/23/03WTC Towers

6 2

WTC Investigation Survey Administration and Report Delivery: Awarded 6/9/03Questionnaires, Interviews and Focus Group Synopsis

5 74 3 Document and Evaluate the Steel Recovered from the WTC Towers Awarded 6/9/03

Hired expertconsultant

Media, Visual and Database Expert with Experience in Obtaining VisualMaterials for the World Trade Center

3 52 5, 6, 7 Fire Safety Engineering Expertise Awarded 12/23/02

Awarded 9/30/02and 10/16/02

1 7 Outside Experts for Occupant Behavior and Evacuation

WTC No. Project Title Status

World Trade Center Investigation Contract Solicitations
Update on Data Collection Efforts

• Significant progress achieved since May 2003

• Reports of critical UL tests performed for the supplier of fireproofing materials• Tapes of N

YPD internal communications concerning WTC terrorist attacks

• Design of WTC internal radio system and FDN

Y radio repeater from PAN

YNJ

• WTC list of occupants issued security badges by PAN

YNJ

• Photos (5616 versus 3100); video clips (4674 versus 3400)• NIST continues to seek photos and videos from the south face of WTC 7

• NIST re

quests for materials that are currently pending with, or not yet loc

provided by organi

zations

• Original contract specifications for WTC towers• Construction logs and maintenance logs for WTC 1, 2, and 7• 9-1-1 tapes and logs, transcripts of about 500 first responder interviews (privile• Supporting documents for McKinsey & Company’s FDN

Y and N

YPD studies

• Complete set of N

YPD records identified in re

quest lists submitted by NIST (in 

• Contents of aircraft (cabin furnishings, cargo, etc.) that contributed to fires (in p• Descriptions of partitions and furnishings in most of the tenant spaces of WTC 

• It is vital that this information be made available to NIST
Update on Fireproofing and Fire Rating 

WTC Floor System

• May 2003 progress report: NIST has not been able to determine the tec

for the selection of fireproofing material for the WTC floor system, and thdetermination of the thickness of fireproofing to achieve the specified 2-

• Contract to Underwriters Laboratories to determine the fire endura

typical WTC floor systems under both as-built and specified condit

• Tested composite floor assembly to include: concrete slab, 2-pairs of m

bridging trusses, fireproofing applied on steel with primer paint

• Three tests will be performed:

• 17 ft span, restrained: current U.S. practice, typical furna

• 35 ft span, restrained: twice typical si

ze; full-scale 35-ft a

• 35 ft span, unrestrained: bound effect of thermal restraint

• Additional rods and double angle structural members to be placed within 

evaluate effect of different fireproofing thicknesses

• Additional testing and analysis underway to estimate condition of f

prior to 9/11 and after airplane impact
Update on Analysis of Structural Steel

• NIST has 236 pieces of WTC steel in its possession; NIST believes t

of steel from the WTC towers is adequate for purposes of its investi

• vast majority are of significant si

ze (exterior column-spandrel panels

wide flange sections, floor trusses, channels); smaller pieces such a

• roughly 1/4 to 1/2 percent of 200,000 tons of steel used in WTC towe

of impact and fire damage emphasized in selection of steel piec

• NIST has all 14 specified steel grades for exterior panels; 2 spe

that represent 99 percent of core columns; and both specified gfloor bar joists

• Specified steel grades vary in strength from 36,000 psi to 100,000 p

• 127 room temperature tensile tests conducted so far (per ASTM A37

E8) on specimens taken from 36 distinct steel pieces and representing ngrades of steel; additional room temperature testing underway

• Room temperature properties used in conventional structural design; to b

analy

ze baseline structural performance of WTC towers under wind and 

Update on Analysis of Structural Steel

• Preliminary results sh

measured room tempstrength met the specmany instances excespecifications by 10,0

• Additional steel testing 

• High strain rate lo

use in aircraft impanalysis

• Elevated tempera

in analysis of therstructural respons

• Ongoing work to evalu

the steel building compsystem and their perfoimpact and fire conditiotime of collapse initiatio
0

2468

1012

0 500 1000 1500 

Time, s

2 MW burner off

Maximum HRR for hood

Two Views of WTC-1 Work Station

Full Involvement of Fire near Peak Heat Release Rate

WTC Fire Model Input Study

Motivation for workstation burns• Computer workstations major fuel source• Combustibles – at least 200 kg per 2.4 m × 2.4 • 778 workstations on 5 floors most affected (94 • Input for Fire Dynamics Model

Test design• 4 tests of workstation/loadin• 2 tests with jet fuel added, 2 • 2 MW line burner source to 

between cubicles

• 2.7 m ceiling with 0.6 m lip t

feedback

• 1 test with same workstation 
First-Person Data on Occupant Behavio

Evacuation, and Emergency Response

• NIST’s study of WTC evacuation and emergency response r

systematic collection of first-person data from:

• Survivors (occupants, first responders, others with safety respo• Families of victims who were in touch with victims after aircraft • Individuals with operational and command authority

• It is possible to learn from the tragic WTC events, and to 

public safety through the collection and analysis of firstaccounts

• This is an ambitious undertaking and will need active pa

of survivors, current and retired first responders, and faits face-to-face, telephone, and focus group interviews
Scope of Occupant Behavior, Evacuatio

Emergency Response Study

• Occupant behavior and evacuation technologies and practices for ta

• Decision-making and situation awareness• Time-constrained evacuation strategies (e.g., defend-in-place)• Role of floors wardens and fire safety directors• Issues concerning people with disabilities• Human factors issues and design of egress system

• Firefighting technologies and practices for tall buildings

• Means for emergency access, time to reach affected floors• Firefighting versus evacuation• Physical condition of firefighter under high-rise work conditions

• Command, control, and communication systems for emergency resp

• Location of incident command post; mobili

zation, staging, and deployment; log

training; pre-event planning

• Content and timing, among occupants and authorities, within and outside buildi

inter group communications

• Observations of fire/smoke conditions, structural damage, water flow
Multiple Data Sources

• Existing published first-person accounts of WTC evacuati

500 interviews collected and analy

zed

• Communication tapes from Port Authority of N

Y & NJ and 

1000 plus hours of taped recordings

• Filings with the Occupational Safety and Health Administr

survivors and families of victims; over 50 written statemen

• Documents from Port Authority, FDN

Y, N

YPD, and others 

of egress and emergency communication systems; WTC history; WTC evacuation planning and drills; emergency rpreparedness and operational data

• Photographic and video data on occupant behavior, evac

emergency response

• First-person data collection from survivors, current an

first responders, and families of victims
Comprehensive Study Methodology

• One of the largest studies of occupant behavior, evacuation, a

emergency response ever conducted

• First-person data collection methodology developed in coopera

social scientists and experts in evacuation and emergency res

• geared toward enhancing recall of directly experienced eve• combines face-to-face, telephone, and focus group intervie• results validated through triangulation with multiple data so

• Review, compare, and analy

ze documentary, photographic, el

and first-person data to:

• develop detailed timeline of events, visual representation o

disaster site

• assess occupant behavior, evacuation, and emergency res• derive findings, conclusions, and recommendations

• The personal privacy and confidentiality of individual resp

will be protected to the maximum extent permitted by law
Preparing for Future Extreme Events

• Buildings are not normally designed for fire protection an

evacuation under extreme conditions

• Critical lack of information on which to base evacuat

emergency response practice, standards, and codes

• Uni

que opportunity to systematically collect and analy

ze 

person accounts that is essential to:

• document and identify areas for improvement from th

of 9/11

• better protect occupants and first responders in future • implement better evacuation and emergency respons

procedures

• This vital pubic safety study needs the active particip

survivors, current and retired first responders, and favictims in via face-to-face, telephone, and focus grouinterviews
Coordination of Field Data Collection

• Cooperating organi

zations representing potential participant gro

• Port Authority of New

York and New Jersey

• New

York City

*

• Fire Department of New

York

• New

York Police Department

• Skyscraper Safety Campaign

• Coordination with concurrent studies:

• Centers for Disease Control and Prevention (CDC)• Columbia University

* NIST and NYC are engaged in negotiations regarding these interviews
Bottom Line

Make all buildings safer

for occupants and first responders
Contact Information

• Survivors, families, and retired first responders may volunte

participate in the face-to-face interviews by contacting:

877-221-7828 (toll free)

• Alternatively, families of victims may volunteer to participat

face-to-face interviews via the following web site:

https://wtc.nist.gov/family

• Anonymous tip line: 888-804-7581 (toll free)• Mail address: NIST World Trade Center Investigation Team

100 Bureau Drive, Stop 8610Gaithersburg, MD 20899-8610

• E-mail: wtc@nist.gov

• Facsimile: 301-975-6122• WTC web site: http://wtc.nist.gov