David Evans, Project Leader

Building and Fire Research Labo

National Institute of Standards and Tec

U.S. Department of Commerce

dave.evans@nist.gov

Federal Building and Fire Safety Inves

of the World Trade Center Disast

Investigation of Active Fire Protectiv

Project 4

June 23, 2004
Disclaimer Disclaimer

Certain commercial entities, equipment, producare identified in this presentation in order to desprocedure or concept adequately or to trace the procedures and practices used. Such identificaintended to imply recommendation, endorsemeimplication that the entities, products, materialsare necessarily the best available for the purpo
OUTLINE OUTLINE

• Objective and Scope• Engineering Teams• Update -- WTC 1, 2, and 7 Fire Histor• Progress:

Sprinkler and Standpipe SystemFire Alarm SystemsSmoke Management Systems
NIST is investigating the design, capabilitie

performance of the installed active fire-protin WTC 1, 2, and 7 and their role in fire conresponse, and fate of occupants and respo

Objective ObjectiveScope

Three systems are being investigated: the system, including the fire standpipes and phoses; the fire alarm system; and the smoksystem. 
Engineering Teams Engineering Teams

• Fire History

Erica Kuligowski, NIST

• Sprinklers, Standpipes and Pre-connected Hoses

Hughes Associates, Inc., Baltimore, MD, under cNIST, Edward Budnick (PI)

• Fire Alarms

Stephen Hill, ATFRolf Jensen and Associates, Inc., Fairfax, VA, unNIST, Raymond Grill (PI)

• Smoke Management

Stuart Dols, NISTHughes Associates, Inc., Baltimore, MD, under cNIST, Michael Ferreira (PI)
Fire History WTC 1, 2, and 7 Fire History WTC 1, 2, and 7

• In addition to the well known 1975 fire and 1993 b

involving multiple sprinklers or multiple standpipe1977 to 1999 were identified from New York City (FDNY) records in NIST’s last WTC Investigation 

• NIST’s working definition of a significant fire has b

include those involving at least one standpipe conwith or without sprinklers. 

3⁄4 Within that expanded definition, 31 additional 

WTC 1 and 2 from 1973 to 1999 were identifie

involved only the use of standpipe hoses. 

• A full reporting of the fire history findings are 

Appendix G of the progress report. Included i

are copies of the FDNY fire reports dealing witselected.
Fire History WTC 1, 2, and 7 Fire History WTC 1, 2, and 7

Two of the 27 fires involving the activation of only standpipe hoses required

evacuations:• On April 19, 1980 at 2:06 p.m.

3⁄4 FDNY received reports of an activated smoke detector in the retu

floor of WTC 1. 

3⁄4 FDNY also received reports of heavy smoke on the 106th floor, l

floor, and heavy odor of smoke in stairways A and B. 

3⁄4 The FDNY report notes that while only one standpipe was used, 

were evacuated from the area. 

3⁄4 The fire cause was labeled as abandoned or discarded material a

material. 

3⁄4 There were no reported injuries or casualties.

• On April 17, 1981 at 9:18 a.m.

3⁄4 FDNY was informed of a fire on the 7th floor and a smoke condit

of WTC 1. 

3⁄4 The fire department hooked up one standpipe and extinguished t

conditioning unit in the “MER” room on the 7th floor. 

3⁄4 The cause of this fire was labeled as a mechanical failure. 

3⁄4 The fire report notes that Port Authority personnel reported an ev

1500 people from floors 9 through 23. 

3⁄4 There were no reported injuries or casualties.
Sprinkler and Standpipe Systems Sprinkler and Standpipe Systems

Preliminary findings for the undamaged and fully op

and standpipe systems.

• Water supply capacity and redundancy met or ex

the art best practices.

• Water supplies to the automatic sprinklers and st

exceeded minimum requirements for high-rise ofprotection in accordance with NFPA 13.

• Generally, sprinkler risers provided single points 

floor level, which creates the potential for single 

• In specific cases, the lack of interconnections for 

standpipe zones resulted in the potential for sing

the standpipe systems.
Water Source at The WTC Complex

Water Source at The WTC Complex

NYC Water Distribution System NYC Water Distribution System

Legend•Red – 20” Plaza Loop•Orange – 16” Connection to Distribution System•Blue – 12” CrossConnection Main for Plaza•Green – 8” Feed Mains for Standpipe and Sprinkler Systems•Cyan

–

Continuation of Distribution System

Finding (1): 

Water supply capacity and redundancy met or exceede

Used with permission of Silver
Sprinkler and Standpipe Systems 

Sprinkler and Standpipe Systems 

Finding (2): Water supplies to the automatic sprinklers and standpipe systems exceeded minimum requirements for highrise office occupancy protection in accordance with NFPA 13. Finding (3): Generally, sprinkler risers provided single points of supply at each floor level,which causes the potential for single point failures. Finding (4): In specific cases, the lack of interconnections for adjacent standpipe zones resulted in the potential for single point failures of the standpipe systems.

LegendBlue – Standpipe systemRed – Sprinkler system Original drawing used wit

Properties.
Fire Alarm Systems WTC 1 & 2 Fire Alarm Systems WTC 1 & 2

WTC 1 & 2 fire alarm systemconsisted of multiple panels distributed within each tower. The distributed panels shared intelligence, information, contcommunication through systecommunication paths.
AUDIO RISER

TELEPHONE RISER 

STAIR C

FIRE ALARM

CLOSET

JANITOR

CLOSET STAIR B 

SPRINK./

Fire Alarm Systems Fire Alarm Systems

Each tower had 4 separate signal communication paths connecting the distributed fire alarm panels between multiple floors.

XNET – “global” 

(24 floors, typical)

MNET – “local” (3 floors) Audio Tones & Voice Announcement AppliancesFirefighter & Warden Telephone
XNET “global”

Provided a communication path between the 4 master fire alarm panels and the headend fire alarm station (manual monitoring and control) distributed within each tower. The path shared monitoring and control information between the fire alarm panels. This system signal communication path went from the lowest level to the highest level of each tower.

TOWER 1 

1st FLOOR (CONCOURSE LEVEL)2nd FLOOR (PLAZA LEVEL)B1 LEVEL5th FLOOR4th FLOOR3rd FLOOR7/8th FLOOR6th FLOOR9th FLOOR10th FLOORB2 LEVELB3 LEVELB4 LEVELB5 LEVELB6 LEVEL43rd FLOOR41/42nd FLOOR44th FLOOR108/109th FLOOR110th FLOOR75/76th FLOOR77th FLOOR78th FLOOR

XNE

XNE
MNET “local”

Provided a communication path for the monitoring and control information between the master fire alarm panels and the distributed slave panels located (typically) every 3 floors. This system signal communication path connected (typically) 24 floors. 

60th FLOOR63rd FLOOR62nd FLOOR61st FLOOR65th FLOOR64th FLOOR

83rd FLOOR

82nd FLOOR81st FLOOR85th FLOOR84th FLOOR74th FLOOR75/76th FLOOR77th FLOOR78th FLOOR79th FLOOR80th FLOOR

XNET

MNET R

MNET 
AUDIO/VOICE

Provided a communication path for the occusignal and voice messages. This system sicommunication path went from the lowest lehighest level of each tower.

FIREFIGHTER AND WARDEN TE

Provided a communication path for the firefigwarden telephone system. This system signcommunication path went from the lowest levhighest level of each tower.
Findings Findings

• The XNET and MNET signal transmission path h

risers and had the capability to provide commun

impact area where the risers where shorted, op

grounded. 

• The Audio/Voice signal transmission path had re

and DID NOT have the capability to continue to 

communication to any panel where the risers wh

• The Firefighter and Warden Telephone signal tra

was a single riser and DID NOT have the capab

provide communication to any panel above the pcable was open, or to ANY connection where thshorted.

• Interviews of firefighters indicated that the firefig

telephone systems were not used on Septembe
Smoke Management Systems Smoke Management Systems

Evaluated Smoke Management 

System Capabilities using CONTAM Model

Examine photographic 

evidence, radio traffic, and survivor/emergency responder testimony to determine factors that may have impacted smoke management system performance

Special attention given to study 

of rapid vertical smoke spread in WTC 1 
Findings Findings

• The smoke management systems in WTC 1 an

provided the capability for a manual smoke purgindividual HVAC zone on a quadrant-by-quadranot initiated on September 11, 2001.

• Had the smoke purge sequence been initiated i

is unlikely the system would have functioned as 

to loss of electrical power and/or damage to the and other structural elements in the impact zon

• Provision of active smoke management system

combination fire/smoke dampers was not requirNYCBC or retroactive provisions in the various enacted after WTC 1 and 2 were constructed forise buildings equipped with automatic sprinkler
Findings (cont.) Findings (cont.)

• None of the potential smoke management syste

evaluated in this investigation would have providpressure differentials to contain smoke for the poimpact damage scenarios, even if these systems of operation after the building sustained damage aircraft impact.

• During the events occurring on September 11, 2

pressurization would have been ineffective in imconditions for occupants trying to exit the buildin
Findings (cont.) Findings (cont.)

• Installation of combination 

fire/smoke dampers in HVAC ductwork, which was not required in WTC 1 or 2, would have acted to slow the development of hazardous conditions on the uppermost floors of the building.

Damper Location
Status of Project 4 Deliverables Status of Project 4 Deliverables

WTC 1, 2, and 7 Fire History Draft contractor reports to NIST on design, capand performance of active fire protection systemSmoke Management Sprinkler, Standpipe, and Pre-connected Hoses Fire Alarm 

NIST findings and recommendations 
Investigation of Active Fire Protec

Project 4

Thank you.

Comments and Questi