WTC Public Safety Stu

NIST World Trade Center Investiga

Jason Averill, Project Leader

National Institute of Standards and Techn

Building and Fire Research Laborator

This Federal Investigation is 

conducted under the authority of the 

National Construction Safety Team Act (PL 107-231)
WTC Public Safety Stu

Objectives of the NIST Investigat

1. Why and how WTC 1, 2, and 7 collapsed follo

initial impacts of the aircraft in WTC 1 and 2

2. Explain fatalities by location, including all tec

aspects of fire protection, occupant behavioevacuation, and emergency response;

3. Determine procedures and practices used in 

design, construction, operation, and mainteWTC 1, 2, and 7; and

4. Identify areas for improvement to building an

practices, codes, and standards.
WTC Public Safety Stu

Desired Outcomes

• Make buildings safer• Enhance safety of fire and emergency resp• Better protect occupants and property in th• Better emergency response capabilities and 

procedures
WTC Public Safety Stu

Occupant Behavior, Egress, an

Emergency Communications

To determine the behavior and fate of occupants anresponders by collecting and analyzing information 

•occupant behavior•human factors•egress•emergency communications•evacuation system
WTC Public Safety Stu

Fire Service Technology and Guid

To build upon work already done by the Fire DepartmenNew York (FDNY) and McKinsey & Company and: • document what happened during the response by 

services, up to the time of collapse of WTC 7

• identify issues in fire service practice, standards, a• identify alternative practices/technologies • identify R&D needs that advance fire service safety
WTC Public Safety Stu

Methodology for First Person Acc

•Face-to-Face Interviews (~750)

–Designed to maximize accuracy, recall, an

•Telephone Interviews (~800)

–Designed for statistical representativenes

•Focus Groups (~15)

–Designed for in-depth study of specific iss
WTC Public Safety Stu

Face-to-face Interviews

•3 Step Process

•Uninterrupted description of the event•Structured discussion to elicit sequence oactions•Follow-up questions

•Participants Include Occupants, First Responand Families
WTC Public Safety Stu

Telephone Interviews

•Standardized Set of Questions•Statistically representative population 

of occupants from WTC 1 and WTC 2

•Stratification Variables:

• Initial Floor Population Density• Single/Multi-Tenant Floor• Floor Location

4478

110

Stratific

Strat

WTC 1

94 – 98

Zone 3Zone 2Zone 1
WTC Public Safety Stu

Focus Groups

•Detailed Recall of Specific Group Experiences

– 5 Groups of ~10 Occupants of WTC 1, 2, o– 10 groups of ~5 first responders 

( a company or other similar group )
WTC Public Safety Stu

Timeline

Feb 2003 Survey methodology developedSept 2002 External experts on-boardAugust 2004 NIST completes InvestigationJan 2004 Analysis of data collections completeNov 2003 Survey field work completedJune 2003 Survey field work initiatedMay 2003 Survey instruments developed and approvedApril 2003 Survey contractor on-board
WTC Public Safety Stu

For More Information

•Web Site: http://wtc.nist.gov•Email: wtc@nist.gov•Regular WTC Technical Information Reposit

Mail: NIST

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