S. Shyam Sunder, Lead Investigator

Bill Grosshandler, Associate 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 Disast

World Trade Center Investigation Sta

August 26, 2003
Highlights Highlights

• Release of May 2003 Progress Report• Update on Data Collection Efforts• Selection of External Experts and Contractors• Schedule and Challenges• Status of Component Projects• Advisory Committee Feedback
1. Release of May 7, 2003 Progress Rep

1. Release of May 7, 2003 Progress Rep

• Expected coverage and response• Generated valuable feedback and inputs; validated 

technical facts

• Suggestions

• Examine positive aspects of the performance of the buildings as w• Recognize that no office building has ever been designed to withst

the impacts of fuel-laden commercial airliners 

• Terminology: “attacks” more appropriate than “disaster”

• Disaster: A sudden calamitous event bringing great 

damage, loss, or destruction (Merriam-Webster Dictio
2. Update on Data Collection Efforts 2. Update on Data Collection Efforts

• Significant progress achieved since May 2003

• Reports of critical UL tests performed for the supplier of fireproofing mate

• Tapes of NYPD internal communications concerning WTC terrorist attack

• Design of WTC internal radio system and FDNY radio repeater from PAN• WTC list of occupants issued security badges by PANYNJ

• Photos (5616 versus 3100); video clips (4674 versus 3400)

• NIST requests for materials that are currently pending with, or not ye

and/or provided by organizations

• 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 (p

claimed by NYC)

• Supporting documents for McKinsey & Company’s FDNY and NYPD stud

• Complete set of NYPD records identified in request lists submitted by NIS

• Contents of aircraft (cabin furnishings, cargo, etc.) that contributed to fires

• Descriptions of partitions and furnishings in most of the tenant spaces of W

• It is vital that this information be made available to NIST
3. Selection of External Experts and 3. Selection of External Experts and 

Contractors Contractors

• Process nearing completion

• Solicitations issued: 15 (1 replaced w• Awards made: 6 contracts

9 experts (3 solicitations

• Under negotiation: 3 contracts (anticipate by 

• Open solicitations: 2 contracts (anticipate by 

• Solicitation in process: 1 contract (anticipate by 

• Four others hired as expert consultants

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

• Excellent group of contractors and experts to augment NIST in-

capabilities
T

TTTTTSBVUNRLNGWVHDG

16 4 Analysis of Smoke Management Systems, WTC 1, 2, and 7 In process

Open; closes 8/27/03

15 4 Analysis of Active Fire Alarm Systems, WTC 1, 2, and 7

Open; closes 8/29/03

Structural Response of WTC Towers to Fire With/Without Impact Damage

14 6

13 6 Development of WTC 7 Structural Models and Collapse Hypotheses Anticipate by 9/1/03

12 4 Analysis of Sprinklers, Standpipe, Pre-Connected Hoses in WTC 1, 2, 7 Anticipate by 9/1/03

11 2 Analysis of Aircraft Impacts into the WTC Towers Anticipate by 9/1/03

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 Probabilistic Assessment of the WTC Investigation

10 2, 5, 6

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

9 6 Fire Endurance Testing of the WTC Floor System

8 7 World Trade Center Investigation First Person Accounts of Egress Awarded 4/15/03

7 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 7

4 3 Document and Evaluate the Steel Recovered from the WTC Towers Awarded 6/9/03

Hired expert consultant 

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

3 5

2 5, 6, 7 Fire Safety Engineering Expertise Awarded 12/23/02

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

1 7 Outside Experts for Occupant Behavior and Evacuation

WTC No. Project Title Status

World Trade Center Investigation Contract Solicitations
Use of External Experts in Source Selec

Use of External Experts in Source Selec

• Use in an advisory capacity: 

• Independent technical review of proposals• Screening by NIST for bias due to potential conflicts of interest

• Use must be posted in solicitation

• Use in evaluation and consensus ranking:

• Requires determination by agency head that no personnel availabl

agency or any other federal agency

• Agency must make reasonable attempts to demonstrate that no su

federal evaluators can be identified

• Use must be posted in solicitation • DOC procurements rarely use outside evaluators (e.g., use for larg

construction or IT projects)

• Evaluation factors related to experience and past performance allo

of contractor with a proven track record; can be used in lieu of evaexpertise in specific field

• Used external experts in advisory capacity for aircraft impact an

solicitation; too late for use with first-person data collection solic
4. Schedule and Challenges: WTC 4. Schedule and Challenges: WTC 

Investigation Workflow Investigation Workflow

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
Projected Completion Schedule for WTC Projected Completion Schedule for WT

Investigation Investigation

012345678

Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04 Jul-04 Aug-04 

Technical Analysis Draft Chapter of Final Repor

Project
Challenges Challenges

• Massive amounts of data from external sources; significant am

continues to be identified/received (affecting projects 1, 2, 5, 6 

• Level of complexity in fire-structure modeling and collapse ana

(affecting projects 2, 5 & 6)

• Scope and scale of occupant behavior, evacuation, and emerg

response study (affecting projects 7 & 8)

• Process and time for acquiring outside expertise (affecting proj

6 & 7 most)

• IRB and Paperwork Reduction Act (PRA) requirements and pro

(affecting projects 7 & 8)
5. Status of Component Projects: Key 5. Status of Component Projects: Key 

Accomplishments Over Last 12 Months Accomplishments Over Last 12 Months

• Collection and review of massive amounts of data from external 

(over 200 boxes)

• Selection, transportation & identification of steel; increase from 1

pieces

• Determination of mechanical and metallurgical properties of reco

steel

• Methodology and protocols for first-person data collection on oc

behavior, evacuation, and emergency response

• Methodology for assessing the most probable structural collapse 

integrating impact, fire, thermal, structural, and collapse analyse

• Interim report on fireproofing procedures & practices for WTC flo
Key Accomplishments Over Last 12 Mo

Key Accomplishments Over Last 12 Mo

(Contd.) (Contd.)

• Time-sequenced visual analysis of fire and damage to 

towers 

• Fire dynamics and thermal response modeling• Computational interfaces between fire and structural m

and software

• Experimental validation of fire dynamics and thermal-st

models

• Development of structural database and model of WTC 

• Review of extensive PA and NYPD communications da
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 
0 6 12 

Structural Databases, Reference

Models, Baseline Analyses for WTC

Towers

Component Level & Approximate

Analyses

Global Analysis of the Impact

Scenario

Development of Draft Chapter of

Final Report

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

Structural 

Databases

Structural 

Models

Component 

Level Analyses

Simplified Approx. 

Uncertainty 

Analyses

Final Unc

Analy

Structural 

Models

Subassembly 

Impact Analyses

Final 

A

Tower Impact 

Analyses

Contractors: LERA, TBD (Aircraft Impact Analysis)Outside Experts: SOM, D. Parks, Teng & Assoc., D. Veneziano

Baseline Performance 

Analysis

Project 2 Project 2 

– Baseline Structural Performan

Baseline Structural Performan

Aircraft Impact Damage Analysis (Fahim 

Aircraft Impact Damage Analysis (Fahim 
Project 5 Project 5 – Reconstruction of Thermal a

Reconstruction of Thermal a

Tenability Environment (Dick Gann) Tenability Environment (Dick Gann)

0 6 12 

Visual Collection and Timeline

Development

Characterization of Combustibles

Characterization of Partitions

Characterization of Structural

InsulationModel DevelopmentFire Reconstruction

Development of Draft Chapter of

Final Report

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

Outside Experts: H. Nelson, V. Junker

FDS & 

Smokeview

Phase 

1

Final Pre

w/ Uncer

Approximate 

Thermal Inpu

Fire w/ Impac

FDS 

Accuracy Est.

Phase 1 

Experiments

Phase 2 

Experiments

First 

Predictions

Fire w/o 

Impact

Final Report Complete Measurements

Complete 

Collection

Complete 

Analysis
Project 6 Project 6 – Structural Fire Response & C

Structural Fire Response & C

Analysis (John Gross & Terri McAllister) Analysis (John Gross & Terri McAllister)

0 6 12 

Evaluation of Floor & Column

Systems Under Fire

Evaluation of Towers Under Fire w/ &

w/o Aircraft Impact

Testing of Structural Components

Evaluation of Structural Collapse

Sequence of the WTC Towers

Evaluation of Open-web Steel

Trussed Joist Systems in Fire

Evaluation of WTC 7 Under Fire

Development of Draft Chapter of Final

Report

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

Test Collapse 

Initiation Hypothese

Contractors: TBD (WTC 7), TBD (WTC Towers), UL (E119 Testing), TBD (Open-web Outside Experts: D. Veneziano, J. Van Dyck, K. Willam, Teng & Assoc.

Component 

Structural Analysis

Global Analysis w/o 

Impact Damage

Uncertainty 

Analysis Approach

Complete 

1st Test

Construct Test 

Assembly

WTC Floor System 

Fireproofing Interim Report

Past Perf. of Joist 

Systems

Structural 

Model

ID Critical 

Components

WTC Floor System 

Fireproofing Final Report

Comple

Add. Te

Simplified Global 

Analysis of Uncertainty

Global Analysis w/o 

Damage

Simplified Global 

Analysis

Simplified Component 

Analysis
Projects 2, 5 & 6 Interfaces Projects 2, 5 & 6 Interfaces

0 6 12 

Simplified Approach

Project 2Project 5Project 6

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

Tower 

Impact 

Analyses

Simplified Structural-Fire Modeling Effort to 

Integrate & Test Coupled Failure Analyses

Baseline 

Performance 

Analysis

Component Level 

Uncertainty 

Analyses

Structural 

Databases

Structural 

Models

Globa

Uncerta

Analys

Visual 

Assessment

Approx. 

Thermal 

Input Fire 

w/Impact

E119 

Testing

Component 

Structural 

Analysis

Gl

Analy

Im

Dam

Global 

Analysis 

w/o Impact 

Damage &

Fire w/o 

Impact 

Computational 

Interface SAPANSYS
Therm

of St

Stress 

Fire Dynamics

Partial Failure

Load Redistribution

Time-Temperature Curve

E 119 Test

Uncoupled Uncoupled 

Analysis Analysis

Current Method:

Deterministic, Linear and Sequential Analysis 

of Collapse Induced by Fire-Structure Interaction
Therm

of S

Stress 

Fire Dynamics

Structure Collapse

Proposed Method:

Probabilistic, Nonlinear, Coupled Analysis 

of Collapse Induced by Fire-Structure Interaction

Radiative Heat Transfer

Stochastic

Boundary Conditions

Vents

Fire Growth and Spread

Load Redistribution

Coupled Analyses Coupled Analyses
0 6 12 

First Person Accounts of Egress

Field Survey and Instruments

Analysis of Information Collected

Development of Draft Chapter of

Final Report

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

Draft 

Chapter 

Complete

Data Set 

Developed

Final 

Report

Analyses 

Complete

Contractors: NuStats including DataSource, GeoStats, MBC Res. Ctr. Outside Experts: D. Mileti, G. Proulx, N. Groner, H. Nelson

Project 7 Project 7 

– Occupant Behavior, Egress, & Occupant Behavior, Egress, 

Emergency Communications (Jason Av

Emergency Communications (Jason Av

Complete 

Instruments

IRB 

Clearance

OMB PRA 

Clearance

Field Work 

Complete

NYC 

Launch

HHS Cert. of 

Confidentiality
0 6 12 

Data Collection

Field Interviews

Analysis of Information Collected

Development of Draft Chapter of

Final Report

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

Draf

Chapt

Compl

Determine 

Factors of 

Success

ID Al

Pra

Outside Experts: V. Dunn, K. Malley, J. Hodgens

Project 8 Project 8 

– Fire Service Technologies & Fire Service Technologies & 

Guidelines (Randy Lawson) Guidelines (Randy Lawson)

IRB 

Clearance

Field Work 

Complete

Categorize 

Audio Tapes

NYC 

Launch

Complete 

Eval. Of 

Audio Tapes

Complete Eval. 

Of Written 

Evidence

PANYNJ 

95%

FDNY 

95%

NYPD 

95%

HHS Cert. of 

Confidentiality
Projects 7 & 8 Interfaces Projects 7 & 8 Interfaces

0 6 12 

Project 7Project 8

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

Egress Data Set 

Developed

Complete 

Instruments

IRB 

Clearance

OMB PRA 

Clearance

Field Work 

Complete

Analyses 

Complete

Draft Chapter 

Complete

Determine 

Factors of 

Success IRB Clearance Field Work Complete ID Al

Pra

Draft Cha

Comple

Complete 

Eval. Of 

Audio Tapes

Complete 

Eval. Of 

Written 

Evidence

HHS Cert. of 

Confidentiality

HHS Cert. of 

Confidentiality
Project 1 Project 1 – Analysis of Building & Fire C

Analysis of Building & Fire C

And Practices (H.S. Lew & R. Bukowsk

And Practices (H.S. Lew & R. Bukowsk

0 6 12 

Design & Construction of Structural

System

Design & Construction of Fire

Protection & Egress Systems

Fuel System for Power Supply in

WTC 7

Compare Building Regulatory & Code

Requirements

Main. & Mods. To Structural, Fire

Prot. & Egress Systems

Development of Draft Chapter of Final

Report

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

Draft Chapt

Complete

Contractor: Rolf Jensen & Associates including S.K. Ghosh AssociateRosenwasser/Grossman Consulting Engineers 

Final

Compare with Other 

City Codes

Draft Final

Review Final

Provisions

ID Building Regs. After 

Cert. of Occupancy

Final

Document Fuel 

System

Compare with Current 

NYC Codes

Document PANYNJ Final

Guidelines

Doc. Inspection 

Program

Doc. Mods.
0 6 12 

Failure Mechanisms & Damage

Based on Visual Observation

Measured Properties of the Steel,

Weldments & Connections

WTC Steel Documents &

Specifications

Development of Draft Chapter of Final

Report

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

Draft 

Chapter 

Complete

Mech. Prop. Interim 

Report (RT, HT, 

High Strain Rate)

Contractor: Wiss, Janney, Elstner Associates, Inc.

Project 3 Project 3 

– Mechanical & Metallurgical A

Mechanical & Metallurgical A

of Structural Steel (Frank Gayle) of Structural Steel (Frank Gayle)

Models of 

Elevated Temp. 

Deformation

Final Report on 

Observed Damage

Compare RT 

Prop. To Specs.

Est. Max. 

Temp.

Structural 

Steel Specs.

Recommended 

Thermal Prop. 

Values

Interim 

Report

Catalog of 

WTC Steel

Recommended 

RT Mech. 

Prop. Values

Interim 

Report

Mech. Prop. 

Final Report
0 6 12 

Sprinklers, Standpipes, & Preconnected Hoses

Fire Alarm Systems

Smoke Purging Systems

Development of Draft Chapter of

Final Report

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

Draft 

Chapter 

Complete

Sys. Design 

& Install.

Mods. After 

1993

Contractors: TBD (Active Fire Prot. Sys.), TBD (Fire Alarm Sys.), TBD Purging Sys.)

Project 4 Project 4 

– Investigation of Active Fire Investigation of Active Fire 

Protection Systems (Dave Evans) Protection Systems (Dave Evans)

Sys. Design 

& Install.

Water Supply 

Des. & Cap.

Compare 

WTC 1, 2 & 7

System Perf. 

On 9-11

Final

Normal 

Ops.

System Perf. 

On 9-11

Draft 

Report

Final 

Repor

Sys. Design 

& Install.

Normal 

Ops.

Draft 

Report

Final 

Report
6. Advisory Committee Feedback 6. Advisory Committee Feedback

• Feedback on individual WTC investigation projects; 

coupling of Projects 2, 5, and 6

• Suggestions for content of December 2003 progress 

report

• Possible scope and content of session at December 

2003 meeting