William M. Pitts, Research Chem

Building and Fire Research Labo

National Institute of Standards and Tec

U.S. Department of Commerce

wpitts@nist.gov

Federal Building and Fire Safety Inves

of the World Trade Center Disast

Visual Data Collection and A

December 2, 2003
Visual Collection and Time Line De

for WTC 1, 2, and 7 

Purpose: To utilize photographs, v

other relevant information detailed time lines for the growth of fires at the pe

World Trade Center Buildin7 and to organize the inforthat it can be utilized investigation team member
TASK MEMBERS 

Leader: Bill Pitts 

Professionals: Kathy Butler 

Lori Brassell 

NIST Expert: Val Junker Students: Josh Novesel  Victor Ontiversos 

Rochelle Plummer José Sánchez Steven Schelick Laura Sugden Jonathan Demarest Brendan Williams 

Other Important Contributors: Doug Walton  Darren Lowe 

Bud Nelson 
TOPICS 

•Collection and Data Basin•Timing•Initial Damage Patterns•Fire Spread in Towers
Collection of Visual Materi

• Material collected in a variety of ways

oDirect contacts with individuals and 

oPublic appeal

oTransfer of material from other orga

oVideo recordings from broadcast te

• Immense amount of material collected

oOver 6100 photographs catalogued 

185 photographers represented)

o

Approximately 150 hour of videotap

clipped (5726 clips) from more than individuals, news organizations, andocumentaries

Video clips used with permission of Scott Myers.
TIMING 

• Digital Photographs and Video (EXIF and meta da

• Comparison of details (e.g., shadows, smoke and • Goal has been one second accuracy relative to se

time defined to be 9:02:54 am

• Timed to ± 3 seconds: photos (2552 of 6194); vid

TIMES FOR MAJOR EVENTS 

Tower 1 Plane Strike: 8:46:31 am

Tower 2 Plane Strike: 9:02:59 amTower 2 Collapse: 9:58:59 amTower 1 Collapse: 10:28:25 am Tower 7 Collapse: 5:20:52 pm
East Face of WTC 2, 9:26:

KEY FOR TEST ANALYSIS 

Sheet #1: Fire Visible  0 No fire  1 Spot fire  2 Fire visible inside  3 External flaming  9 Can’t see Sheet #2: Smoke  0 No smoke evident  1 “Light smoke”  2 “Heavy smoke”  9 Can’t see Sheet #3: Windows  0 Window open  1 Window in place  9 Can’t see 



■ Windows intact 

■ Windows missing ■ Hidden 

North Ea

South W

WTC 1 Initial Windows Missi
Used with permission of the City of New York.

©2001. New York City Police Department. All ri
■ Windows intact 

■ Windows missing ■ Hidden 

North South 

WTC 2 Initial Windows Missi

SOME RELEVANT VISUAL OBSERVATIONS 

(Part 1) 

● Initial damage and subsequent fire developme

asymmetric (plane strike centered on north fac● Fireballs following plane strike on north, east● Fires “damped down” shortly after initial fireb● Significant damage and early fire growth on n

of east face, and western side of south face 

● Fires on east side of south face are not obse

10:00 am 

● Rapid and extensive fire spread on 97th floor o

starting at 8:56:08 am; by 9:00 am large fires o

floors on north face, center of east face on 94th 

and west side of south face on 96th floor 

● Fires develop and start to spread across east f

after 9:00 am 
SOME RELEVANT VISUAL OBSERVATIONS 

(Part 2) 

● Areas of “typical” fire spread observed 

● Fires moving south on east face of 92nd, 94th

floors 

● Areas of sudden fire development observed 

● Some associated with flashover in offices (e. 

corner on 96th floor around 9:19 am) 

● Some occur in open areas (west side of 96th 

face around 9:54 am) 

● Fires burning on 98th floor on all four faces a● Large fire appeared suddenly on 104th floor o

west face shortly after 10:00 am 

● Large fires grew on multiple floors of east sid

after 10:10 am

● Sudden release of smoke from 92nd floor of n

10:18:48 am followed by rapid appearance omuch of floor
SOME RELEVANT VISUAL OBSERVATIONS 

(Part 1) 

● Initial damage and fire locations are highly asy

strike off center to the east) 

● Fireballs following plane strike on north, east

● Large sections of curtain wall removed on no

faces, broken column on north face 

● No visible damage to west face ● Fires don’t “damp” down to low levels of Tow

● Large debris piles seen in northeast corners 

floors and close to center of north face on 79

● Small fires only on south face, extensive fires 

and 83rd floors of east face 

● Fires located on debris piles on east and nor

long periods 

● There is a “cold” area between the debris pile

face that is roughly 45 feet wide and covers t

82nd floors 
SOME RELEVANT VISUAL OBSERVATIONS 

(Part 2) 

● Fires are less active than observed for Tower 1

changes ● Heavy flames erupt on 83rd floor of north face 

of the “cold” area at 9:29:10 am, at 9:35:45 asuddenly appear on this floor near the center 

● Heavy smoke and flames suddenly appear o

large extent of 79th and 80th floors around 9:3

decrease abruptly around 9:36:30 am, fires tback 

● Flames appear on the 82nd floor just to right o

the north face around 9:54 am 

● Flames spread across most of the 79th floor o

to collapse 

● Release of heavy smoke and rapid growth of 

western half of the 80th floor occurs on the so

at 9:56:37 am 
SOME RELEVANT VISUAL OBSERVATIONS 

(Part 3) 

● Visual evidence for collapsed floors 

● Photos and videos show a hanging object tha

the 83rd floor draped across windows on the 8

object sinks lower at later times 

● Similar objects, likely localized portions of the 

83rd floors, are visible through windows on ththe north face 

● Molten material pours from the upper region 

starting at 9:51:52 am