High-rise Office Building Fire One Meridian
Plaza Philadelphia, Pennsylvania (February 23, 1991)
|This report on the Philadelphia, Pennsylvania, One Meridian Plaza
fire documents one of the most significant high-rise fires in United
States’ history. The fire claimed the lives of three Philadelphia
firefighters and gutted eight floors of a 38-story fire-resistive
building causing an estimated $100 million in direct property loss
and an equal or greater loss through business interruption. Litigation
resulting from the fire amounts to an estimated $4 billion in civil
damage claims. Twenty months after the fire this building, one of
Philadelphia’s tallest, situated on Penn Square directly across
from City Hall, still stood unoccupied and fire-scarred, its structural
integrity in question.
This fire is a large scale realization of fire risks that have
been identified on many previous occasions. The most significant
new information from this fire relates to the vulnerability of the
systems that were installed to provide electrical power and to support
fire suppression efforts. In this incident there was an early loss
of normal electrical power, a failure of the emergency generator
and a major problem with the standpipe system, each of which contributed
to the final outcome. These experiences should cause responsible
individuals and agencies to critically reexamine the adequacy of
all emergency systems in major buildings.
When the initial news reports of this fire emerged, attention focused
on how a modern, fire-resistive high-rise in a major metropolitan
city with a well-staffed, well-equipped fire department could be
so heavily damaged by fire. The answer is rather simple -- fire
departments alone cannot expect or be expected to provide the level
of fire protection that modem high-rises demand. The protection
must be built-in. This fire was finally stopped when it reached
a floor where automatic sprinklers had been installed.
This report will demonstrate that the magnitude of this loss is
greater than the sum of the individual problems and failures which
produced it. Although problems with emergency power systems, standpipe
pressure reducing valves, fire alarm systems, exterior fire spread,
and building staff response can be identified, the magnitude of
this fire was a result of the manner in which these factors interacted
with each other. It was the combination of all of these factors
that produced the outcome.
At the time of the One Meridian Plaza fire, the three model fire
prevention codes had already adopted recommendations or requirements
for abating hazards in existing high-rise buildings. Each of the
model building codes contains explicit requirements for fire protection
|A fire on the 22nd floor of the 38-story Meridian Bank Building,
also known as One Meridian Plaza, was reported to the Philadelphia
Fire Department on February 23, 1991 at approximately 2040 hours and
burned for more than 19 hours. The fire caused three firefighter fatalities
and injuries to 24 firefighters. The 12-alarms brought 51 engine companies,
15 ladder companies, 11 specialized units, and over 300 firefighters
to the scene. It was the largest high-rise office building fire in
modern American history -- completely consuming eight floors of the
building -- and was controlled only when it reached a floor that was
protected by automatic sprinklers. A table summarizing the key aspects
of the fire is presented on the following pages.
The Fire Department arrived to find a well-developed fire on the
22nd floor, with fire dropping down to the 21st floor through a
set of convenience stairs. (For an elevation drawing of the building
and the 22nd floor plan see Appendix A.) Heavy smoke had already
entered the stairways and the floors immediately above the 22nd.
Fire attack was hampered by a complete failure of the building’s
electrical system and by inadequate water pressure, caused in part
by improperly set pressure reducing valves on standpipe hose outlets.
SUMMARY OF KEY ISSUES
|Issues Origin and Cause Fire Alarm System Comments The fire
started in a vacant 22nd floor office in a pile of linseed oil-soaked
rags left by a contractor. The activation of a smoke detector
on the 22nd floor was the first notice of a possible fire. Due
to incomplete detector coverage, the fire was already well advanced
before the detector was activated. Building Staff Response Building
employees did not call the fire department when the alarm was
activated. An employee investigating the alarm was trapped when
the elevator opened on the fire floor and was rescued when personnel
on the ground level activated the manual recall. The Fire Department
was not called until the employee had been rescued. Alarm Monitoring
Service The private service which monitors the fire alarm system
did not call the Fire Department when the alarm was first activated.
A call was made to the building to verify that they were aware
of the alarm. The building personnel were already checking the
alarm at that time. Electrical Systems Installation of the primary
and secondary electrical power risers in a common unprotected
enclosure resulted in a complete power failure when the fire-damaged
conductors shorted to ground. The natural gas powered emergency
generator also failed.
|Fire Barriers Unprotected penetrations in fire-resistance
rated assemblies and the absence of fire dampers in ventilation
shafts permitted fire and smoke to spread vertically and horizontally.
Ventilation openings in the stairway enclosures permitted smoke
to migrate into the stairways, complicating firefighting. Unprotected
openings in the enclosure walls of 22nd floor electrical closet
permitted the fire to impinge on the primary and secondary electrical
|Standpipe System and Improperly installed standpipe valves
Pressure Reducing Valves (PRVs) provided inadequate pressure
for fire department hose streams using 1 3/4-inch hose and automatic
fog nozzles. Pressure reducing valves were installed to limit
standpipe outlet discharge pressures to safe levels. The PRVs
were set too low to produce effective hose streams; tools and
expertise to adjust the valve settings did not become available
until too late.
|Locked Stairway Doors For security reasons, stairway doors
were locked to prevent reentry except on designated floors.
(A building code variance had been granted to approve this arrangement.)
This compelled firefighters to use forcible entry tactics to
gain access from stairways to floor areas
|Exterior Fire Spread “Autoexposure” Exterior vertical
fire spread resulted when exterior windows failed. This was
a primary means of fire spread.
|Structural Failures Fire-resistance rated construction features,
particularly floor-ceiling assemblies and shaft enclosures (including
stair shafts), failed when exposed to continuous fire of unusual
intensity and duration.
|Automatic Sprinklers The fire was eventually stopped when
it reached the fully sprinklered 30th floor. Ten sprinkler heads
activated at different points of fire penetration.
One Meridian Plaza is a 38-story high-rise office building, located
at the comer of 15th Street and South Penn Square in the heart of
downtown Philadelphia, in an area of high-rise and mid-rise structures.
On the east side, the building is attached the 34-story Girard Trust
Building and it is surrounded by several other high-rise buildings.
The front of the building faces City Hall.
One Meridian Plaza has three underground levels, 36 above ground
occupiable floors, two mechanical floors (12 and 38), and two rooftop
helipads. The building is rectangular in shape, approximately 243
feet in length by 92 feet in width (approximately 22,400 gross square
feet), with roughly 17,000 net usable square feet per floor. (See
Appendix A for floor plan.) Site work for construction began in
1968, and the building was completed and approved for occupancy
Construction was classified by the Philadelphia Department of Licenses
and Inspections as equivalent to BOCA Type 1B construction which
requires 3-hour fire rated building columns, 2-hour fire rated horizontal
beams and floor/ceiling systems, and l-hour fire rated corridors
and tenant separations. Shafts, including stairways, are required
to be 2-hour fire rated construction, and roofs must have l-hour
fire rated assemblies.
The building frame is structural steel with concrete floors poured
over metal decks. All structural steel and floor assemblies were
protected with spray-on fireproofing material. The exterior of the
building was covered by granite curtain wall panels with glass windows
attached to the perimeter floor girders and spandrels.
The building utilizes a central core design, although one side
of the core is adjacent to the south exterior wall. The core area
is approximately 38 feet wide by 124 feet long and contains two
stairways, four banks of elevators, two HVAC supply duct shafts,
bathroom utility chases, and telephone and electrical risers.
The building has three enclosed stairways of concrete masonry construction.
Each stairway services all 38 floors. The locations of the two stairways
within the building core shift horizontally three or four times
between the ground and the 38th floor to accommodate elevator shafts
and machine rooms for the four elevator banks. Both of these stairways
are equipped with standpipe risers.
Adjacent to the stairway enclosures are separate utility and HVAC
shafts. There are pipe and duct penetrations through the shaft and
stairway enclosure walls. The penetrations are unprotected around
the sleeved pipes and fire dampers are not installed in WAC ducts
penetrating the fire-resistance rated wall assemblies. This effectively
creates many openings between the utility shafts, and the individual
floors, primarily in the plenum area above the ceilings, as well
as between the shafts and the stairway enclosures.
The third enclosed stairway is located at the east end of the building.
This stairway attaches the floors of the Meridian Plaza to the corresponding
floors of the Girard Trust Building. Adjacent to the east stairway
is an additional enclosed utility shaft which also has pipe and
duct penetrations through the shaft enclosure walls. There are no
fire or smoke barriers around the sleeved pipes and no fire dampers
in the HVAC ducts that penetrate the shaft walls.
Elevator service is provided by four zoned elevator banks identified
as A through D. Elevator Bank A serves floors 2-11. Elevator Bank
B has two shafts which enclose seven elevators: six are passenger
elevators that serve floors 12-21, and one is a freight elevator
that serves floors 22-38. Elevator Bank C serves floors 21-29, and
Elevator Bank D serves floors 29-
37. The elevator shafts are constructed of concrete and masonry
and extend from the first floor or lower levels to the highest floor
served by the individual elevator banks. At the top of each elevator
bank is the associated elevator equipment room.
The elevator shafts that serve the upper floors are express rise
and do not have openings to the lower floors. Only the Bank C passenger
elevators and the freight elevator served the fire floors. The elevator
shafts did not appear to play a significant role in the spread of
Each elevator lobby is equipped with a smoke detector that, when
activated, recalls the elevator cars to the first floor lobby. Firefighter’s
service (elevator recall) features were added in 1981 under provisions
Heating, Ventilation, and Air Conditioning
The heating, ventilation, and air conditioning (HVAC) system is
composed of four air handling systems. Two systems are located in
the 38th floor mechanical room and service the east and west halves
of the upper floors. The other two systems are located in the 12th
floor mechanical room and service the east and west halves of the
lower floors. Each system supplies air to its respective floors
through one or two supply air shafts located within the building
core and receives return air from its associated return air shafts.
Return air shafts are located at each of the four building comers.
Upon examination at selected locations, the HVAC supply and return
air shafts did not appear to have fire dampers at the duct penetrations
on each floor.
The bathroom utility piping extends through the 38 floors through
pipe chases that are formed by the space between two walls. These
pipe chases transfer location as the bathroom locations change floor
to floor. Upon a sample examination of the pipe chases, it was found
that floor penetrations were not closed or sealed to maintain the
integrity of the fire-resistance rated floor/ceiling assemblies.
Electrical and Communications Risers
The electrical and telephone risers are enclosed in separate rooms
on each floor. The rooms are located directly above one another
and are intended to function as vertical shafts, with rated separations
required at horizontal penetrations from the shafts into floor and
ceiling spaces at each level. Within the telephone and electrical
rooms, unprotected penetrations of the floor assemblies allow conduits
and exposed wires to travel from floor to floor. Several breaches
of fire-resistance rated construction were observed in the walls
separating the electrical and telephone rooms from the ceiling plenums
and occupied spaces on each floor.
The building electrical system receives power from two separate
electrical substations and is backed-up by an emergency generator.
The two sources of power are arranged so that the load would automatically
transfer to the second source upon failure of the first. Electrical
power for One Meridian Plaza and four adjacent buildings is distributed
from the basement of 1414 S. Penn Square.
The electric service enters the building via the basement from
the adjoining building and is distributed to the 12th and 38th floor
mechanical rooms via the electrical risers in the building core.
From the 12th and 38th floor mechanical rooms, electrical power
is distributed to the major mechanical systems and to a buss bar
riser, which services distribution panels on the individual floors.
Emergency power was provided by a 340 kw natural gas-fired generator
located in the 12th floor mechanical room. The generator was sized
to supply power for emergency lighting and the fire alarm system,
the fire pump located on the 12th floor and one car in each bank
of elevators. The generator’s fuel was supplied by the building’s
natural gas service. This generator was not required by the building
code, since the building’s electrical power was supplied by
two separate substations.
The generator was reported to have been tested weekly. The last
recorded test date was January 30, almost four weeks before the
fire, and the maintenance records indicate that problems were encountered
during engine start-up under load conditions at that time. During
a detailed inspection following that test, a damaged part was discovered
and replaced. After the repair, the generator was started without
a load and appeared to work properly, but no subsequent tests were
performed to determine if the problems persisted under load conditions.
Records of earlier maintenance and test activity suggest that load
tests were performed only occasionally. Test and maintenance records
indicate a long history of maintenance problems with the emergency
generator system. Many of these problems became manifest during
or immediately after conducting tests under load.
|FIRE PROTECTION SYSTEMS
At the time of construction,
the Philadelphia Building Code required only a local fire alarm
system with manual stations at each exit and smoke detectors in
the supply and return air shafts. Hose stations supplied from the
domestic water service and portable fire extinguishers were required
for occupant use. Dry standpipes were installed for fire department
use. Below ground levels were required to be provided with automatic
As a result of local code changes, several improvements to the
fire protection systems were made in the years following the building’s
In 1981, the Philadelphia Department of Licenses and Inspections
implemented amendments to the fire code which were intended to address
the life safety of high-rise building occupants. These requirements
included installation of stair identification signs, provisions
to permit stairway re-entry, and installation of smoke detection
in common areas in the path of access to exits. The “common
areas” provision of the code was intended to address corridors
and exit passageways in multi-tenant floors. The smoke detector
requirements were interpreted in such a way that single tenant “open
plan” floors were only required to have detectors installed
at the exits; the entire floor, although open, was not considered
a “common area.” Smoke detectors were also installed
in the return air plenum adjacent to the return air shaft intakes
in each comer of the building. These provisions required that building
owners file permits for this work within one year of the code change.
City records do not indicate when this work was performed in this
particular building or if it was inspected and approved.
Fire Detection and Alarm Systems
At the time of construction, One Meridian Plaza was equipped with
a coded manual fire alarm system with pull stations installed adjacent
to each of the three exit stairwells on each floor. Smoke detection
was provided in the major supply and return air ducts at the mechanical
After the 1981 fire code amendments were! enacted, the hardware
on stairway doors was required to allow access from stairs back
to floor areas or to be unlocked automatically in the event that
the fire alarm was activated. One Meridian Plaza was granted a variance
from this provision and generally had unlocked doors every three
Approximately one and a half years before the fire, a public address
system was installed throughout the building. This system was operable
from the lobby desk and had the capability of addressing floors,
stairways, elevator machine rooms, and elevators. Two-way communication
was possible with elevators and elevator machine rooms.
As additional devices and systems were installed, they were connected
to the fire alarm system to sound through the single-stroke bells
originally installed with the manual fire alarm system. Smoke detector
and water flow signals were assigned their own codes to allow annunciation
not only at the lobby but throughout the building for those members
of the building staff who knew the codes.
The occupant use standpipe system, which was connected to the domestic
water supply, provided two outlets per floor with 100 feet of 1
l/2-inch hose and a nozzle. The hose cabinets were located in corridors
on each floor.
A dry standpipe system was originally installed with 6 inch risers
in the west and center stair towers and outlets for 2 l/2 fire department
hose lines at each floor level. This system was converted to a wet
riser system in 1988, to supply automatic sprinklers on some of
the upper floors. An 8 inch water supply was provided to deliver
water to two 750 gpm electric fire pumps, one in the basement and
one on the 12th floor.
The basement pump supplied the lower standpipe zone (floors B-12)
while the 12th floor pump served the upper zone (floors 13-38).
There was no standpipe in the east stair tower.
A November 1988 Board of Building Standards decision permitted
both zones to be served by a common fire department connection,
as part of a plan that would provide for the installation of automatic
sprinklers on all floors by November 1993.2
Due to the height of the zones and the installation of fire pumps,
pressures exceeded the 100 psi limit permitted by NFPA 14, Installation
of Standpipe and Hose Sytems at the standpipe hose outlets on several
lower floors in each zone. Pressure restricting devices, which limit
the discharge through standpipe outlets by restricting the orifice,
were installed on the mezzanine and second floor levels and on floors
26 through 30. Pressure reducing valves, which regulate both static
pressure and discharge pressure under variable flow conditions,
were installed on floors 13 through 25.
Both types of devices prevent dangerous discharge pressures from
hose outlets at the lower floors of each standpipe zone. The Philadelphia
Fire Department investigators report that the plans submitted at
the time the standpipes were converted did not indicate that PRVs
were to be installed.
Only the service floors located below grade were protected by automatic
sprinklers at the time of construction. Conversion of the dry standpipe
to a wet system with fire pumps facilitated the installation of
automatic sprinklers throughout the building. At the request of
selected tenants, sprinklers were installed on several floors during
renovations, including all of the 30th, 31st, 34th, and 35th floors,
and parts of floors 11 and 15. Limited service sprinklers, connected
to the domestic water supply system, were installed in part of the
37th floor. The building owners had plans to install sprinklers
on additional floors as they were renovated.
At approximately 2023 hours on February 23,1991, a smoke detector
was activated on the 22nd floor of the One Meridian Plaza building.
The activated detector is believed to have been located at the entrance
to the return air shaft in the northeast comer of the building.
At that time there were three people in the building, an engineer
and two security guards.’ The alarm sounded throughout the
building and elevator cars automatically returned to the lobby.
The building engineer investigated the alarm using an elevator on
manual control to go to the 22nd floor. The central station monitoring
company that served the building reportedly called the guard desk
in the lobby to report the alarm. The call came in before the engineer
reached the fire floor, and the alarm company was told that the
source of the alarm was being investigated. The alarm company did
not notify the Fire Department at that time.
When the elevator doors opened at the 22nd floor, the engineer
encountered heavy smoke and heat. Unable to reach the buttons or
to leave the elevator car to seek an exit, the building engineer
became trapped. He was able to use his portable radio to call the
security guard at The building staff regulated the after-hours population
of the building through a lighting request system where tenants
lights would be turned on for the duration of their work. In addition,
there was a security system in the building that recorded any passage
through stairwell doors. the lobby desk requesting assistance. Following
the trapped engineer’s instructions, the security guard in
the lobby recalled the elevator to the ground floor using the Phase
II firefighter’s safety feature.
The second security guard monitored the radio transmissions while
taking a break on the 30th floor. This guard initially mistook the
fire alarm for a security alarm believing that he had activated
a tenant’s security system while making his rounds. He evacuated
the building via the stairs when he heard the building engineer
confirm there was a fire on the 22nd floor.
The roving guard reported that as he descended from the 30th floor
the stairway was filling with smoke. He reached the ground level
and met the engineer and the other security guard on the street
in front of the building.
The Philadelphia Fire Department report on the incident states
that the lobby guard called the alarm monitoring service to confirm
that there was an actual fire in the building when the engineer
radioed to her from the 22nd floor. After meeting outside and accounting
for each other’s whereabouts the three building personnel
realized that they had not yet called the Fire Department.
The first call received by the Philadelphia Fire Department came
from a passerby who used a pay telephone near the building to call
911. The caller reported smoke coming from a large building but
was unable to provide the exact address. While this call was still
in progress, at approximately 2027 hours, a call was received from
the alarm monitoring service reporting a fire alarm at One Meridian
The Philadelphia Fire Department dispatched the first alarm at
2027 hours consisting of four engine and two ladder companies with
two battalion chiefs. The first arriving unit, Engine 43, reported
heavy smoke with fire showing from one window at approximately the
mid-section of the building at 2031 hours. A security guard told
the first arriving battalion chief that the fire was on the 22nd
floor. Battalion Chief 5 ordered a second alarm at 2033 hours.
While one battalion chief assumed command of the incident at the
lobby level, the other battalion chief organized an attack team
to go up to the fire floor. (The Philadelphia Fire Department’s
“High-rise Emergency Procedures” Operation Procedure
33 is presented in Appendix C.) The battalion chief directed the
attack team to take the low-rise elevators up the 11th floor and
walk up from there.
Electrical Power Failure
Shortly after the battalion chief and the attack team reached the
11th floor there was a total loss of electrical power in the building.
This resulted when intense heat from the fire floor penetrated the
electrical room enclosure. The heat caused the cable insulation
to melt resulting in a &ad short between the conductor and the
conduit in both the primary and secondary power feeds, and the loss
of both commercial power sources. The emergency generator should
have activated automatically, but it failed to produce electric
power. These events left the entire building without electricity
for the duration of the incident in spite of several efforts to
restore commercial power and to obtain power from the generator.
This total power failure had a major impact on the firefighting
operations. The lack of lighting made it necessary for firefighters
to carry out suppression operations in complete darkness using only
battery powered lights. Since there was no power to operate elevators,
firefighters were forced to hand carry all suppression equipment
including SCBA replacement cylinders up the stairs to the staging
area that was established on the 20th floor. In addition, personnel
had to climb at least 20 floors to relieve fellow firefighters and
attack crews increasing the time required for relief forces to arrive.
This was a problem for the duration of the incident as each relief
crew was already tired from the long climb before they could take
over suppression duties from the crews that were previously committed.
As the initial attack crews made their way toward the 22nd floor
they began to encounter smoke in the stairway. At the 22nd floor
they found the west stair tower door locked. The door was already
warped and blistering from the heat, and heavy fire could be seen
through the door’s wire glass window. A 1 3/4-inch hand line
was stretched up the stairway from a standpipe connection on the
floor below and operated through the window while a ladder company
worked on forcing open the door.It took several minutes before the
door could be forced open and an attempt could be made to advance
onto the fire floor with the 13/4-inch attack line. The crews were
not able to penetrate onto the 22nd floor due to the intense heat
and low water pressure they were able to obtain from their hose
line. An entry was also made on the 21st floor where the firefighters
were able to see fire on the floor above through the open convenience
stair. They attempted to use an occupant hose line to attack the
fire but could not obtain water from that outlet. They then connected
a 1 3/4 inch attack line to the standpipe outlet in the stairway,
but they could not obtain sufficient pressure to attack the flames.
A Tactical Command Post was established on the 21st floor and a
staging area was set up on floor 20.
By this time fire was visible from several windows on the 22nd
floor and crews outside were evacuating the area around the building
and hooking up supply lines to the building’s standpipe connections.
As flames broke through several more windows around a major portion
of the fire floor, the floor above was subject to autoexposure from
flames lapping up the side of the building. Additional alarms were
called to bring personnel and equipment to the scene for a large
scale fire suppression operation.
As the fire developed on the 22nd floor, smoke, heat, and toxic
gases began moving through the building. Vertical fire extension
resulted from unprotected openings in floor and shaft assemblies,
failure of fire-resistance rated floor assemblies, and the lapping
of flames through windows on the outside of the building.
Water Supply Problems
The normal attack hose lines used by the Philadelphia Fire Department
incorporate 1 3/4-inch hose lines with automatic fog nozzles designed
to provide variable gallonage at 100 psi nozzle pressure. The pressure
reducing valves in the standpipe outlets provided less than 60 psi
discharge pressure, which was insufficient to develop effective
fire streams. The pressure reducing values (PRVs) were field adjustable
using a special tool. However, not until several hours into the
fire did a technician knowledgeable in the adjustment technique
arrive at the fire scene and adjust the pressure on several of the
PRVs in the stairways.
When the PRVs were originally installed, the pressure settings
were improperly adjusted. Index values marked on the valves did
not correspond directly to discharge pressures. To perform adjustments
the factory and field personnel had to refer to tables in printed
installation instructions to determine the proper setting for each
floor level.4 For more detailed information about PRVs see Appendices
D and E.
Several fire department pumpers were connected to the Fire Department
connections to the standpipe system in an attempt to increase the
water pressure. The improperly set PRVs effectively prevented the
increased pressure in the standpipes from being discharged through
the valves. The limited water supply prevented significant progress
in fighting the fire and limited interior forces to operating from
defensive positions in the stairwells. During the next hour the
fire spread to the 23rd and 24th floors primarily through autoexposure,
while firefighters were unable to make entry onto these floors due
to deteriorating heat and smoke conditions and the lack of water
pressure in their hose lines. Windows on the 22nd floor broke out
and the 23rd and 24th floor windows were subject to autoexposure
from flames lapping up the sides of the building.
On the street below pedestrians were cleared from the area because
of falling glass and debris as more and more windows were broken
out by the fire. Additional hose lines were connected to the standpipe
connections, attempting to boost the water pressure in the system.
However, the design of the PRVs did not allow the higher pressures
to reach the interior hose streams. Additional alarms were requested
to bring a five-alarm assignment to the scene.
Three Firefighters Lost
As firefighters attempted to make entry to the burning floors from
the stairways, heavy smoke continued to build up within the stair
shafts and banked down from the upper floors. An engine company
was assigned to attempt to open a door or hatch to ventilate the
stairways at the roof level to allow the smoke and heat to escape.
A Captain and two firefighters from Engine 11 started up the center
stair from the 22nd floor with this assignment. Engine 11 subsequently
radioed that they had left the stairway and were disoriented in
heavy smoke on the 30th floor. Attempts were made to direct the
crew by radio to one of the other stairways.
Shortly thereafter a radio message was received at the Command
Post from Engine 11’s Captain requesting permission to break
a window for ventilation. This was followed moments later by a message
from a crew
The pressure reducing valves in the vicinity of the fire floor
(floors 18 through 20) were set at “80” on the valve
index which corresponded to a discharge pressure between 55 and
57 psi, depending on the elevation. This would provide a nozzle
pressure of 40 to 45 psi at the end of a 150 to 200 foot hose line.
member of Engine 11 reporting that “the Captain is down.”
Approval was given to break the window and rescue efforts were initiated
to search for the crew. Search teams were sent from below and a
helicopter was requested to land a team on the roof. The search
teams were able to reach the 30th floor, which was enveloped in
heavy smoke, but were unable to find the missing firefighters. They
then searched the floors above without success. An eight member
search team became disoriented and ran out of air in the mechanical
area on the 38th floor, while trying to find an exit to the roof.
They were rescued by the team that had landed on the roof and were
transported back to ground level by the helicopter.
Several attempts were made to continue the search, until helicopter
operations on the rooftop had to be suspended due to the poor visibility
and the thermal drafts caused by the heat of the fire. The helicopter
crew then attempted an exterior search, using the helicopter’s
searchlight, and at 0117 located a broken window on the southeast
comer of the 28th floor, in an area that could not be seen from
any of the surrounding streets. Another rescue team was assembled
and finally located the three missing member just inside the broken
window on the 28th floor at approximately 0215. At that time the
fire was burning on the 24th and 25th floors and extending to the
The victims were removed to the Medical Triage Area on the 20th
floor, but resuscitation efforts were unsuccessful and they were
pronounced dead at the scene. An estimated three to four hours had
elapsed since they had reported that they were in trouble and all
had succumbed to smoke inhalation.’
The three deceased members of Engine Company 11 were Captain David
P. Holcombe (age 52), Firefighter Phyllis McAllister (43), and Firefighter
James A. Chappell (29).
Prior to being assigned to this task, the crew had walked up to
the fire area wearing their full protective clothing and SCBAs and
carrying extra equipment. It is believed that they started out with
full SCBA cylinders, but it is not known if they became disoriented
from the heavy
5 The exact time that Engine 11 was assigned to attempt ventilation
and the time the crew reported they were in trouble are not known,
since the tactical radio channel they were using is not recorded
and detailed time records of this event were not maintained during
the incident. Estimates from individuals who were involved suggest
that the assignment was made between 2130 and 2200 hours and search
efforts were initiated between 2200 and 2230 hours. The bodies were
located at approximately 0215 hours. smoke in the stairway, encountered
trouble with heat build-up, or were exhausted by the effort of climbing
28 floors. Some combination of these factors could have caused their
predicament. Unfortunately, even after breaking the window they
did not find relief from the smoke conditions which were extremely
heavy in that part of the building.
Continuing Efforts to Improve Water Supply
Because of the difficulty in obtaining an adequate water supply,
a decision was made to stretch 5-inch lines up the stairs to supply
interior attack lines. The first line was stretched up the west
(#l) stairwell to the 24th floor level and was operational by 0215,
approximately six hours into the fire. At 0221, a 12th alarm was
sounded to stretch a second line, in the center (#2) stair. At 0455,
a third 5-inch line was ordered stretched, in the east (#3) stair.
The operation in the east stair was discontinued at the 17th /floor
level at 0600. While the 5-inch lines were being stretched, a sprinkler
contractor arrived at the scene and began manually adjusted the
pressure reducing valves on the standpipe connections. This improved
the discharge pressure in the hoses supplied by the standpipe system,
finally providing normal handline streams for the interior fire
suppression crews. At this point, however, the fire involved several
floors and could not be contained with manual hose streams.
Firefighting Operations Suspended
All interior firefighting efforts were halted after almost 11 hours
of uninterrupted fire in the building. Consultation with a structural
engineer and structural damage observed by units operating in the
building led to the belief that there was a possibility of a pancake
structural collapse of the fire damaged floors. Bearing this risk
in mind along with the loss of three personnel and the lack of progress
against the fire despite having secured adequate water pressure
and flow for interior fire streams, an order was given to evacuate
the building at 0700 on February 24. At the time of the evacuation,
the fire appeared to be under control on the 22nd though 24th floors.
It continued to bum on floors 25 and 26 and was spreading upward.
There was a heavy smoke condition throughout most of the upper floors.
The evacuation was completed by 0730.
After evacuating the building, portable master streams directed
at the fire building from several exposures, including the Girard
Building #l and One Centre Plaza, across the street to the west
were the only firefighting efforts left in place.
The fire was stopped when it reached the 30th floor, which was
protected by automatic sprinklers. As the fire ignited in different
points this floor level through the floor assembly and by autoexposure
through the windows, 10 sprinkler heads activated and the fires
were extinguished at each point of penetration. The vertical spread
of the fire was stopped solely by the action of the automatic sprinkler
system, which was being supplied by Fire Department pumpers. The
30th floor was not heavily damaged by fire, and most contents were
salvageable. The fire was declared under control at 3:Ol p.m., February
The heated products of combustion from a fire have a natural buoyancy,
which causes them to accumulate in the upper levels of a structure.
In a high-rise building the stairways, elevator shafts, and utility
shafts are natural paths for the upward migration of heated products
Stack effect is a natural phenomenon affecting air movement in
tall buildings. It is characterized by a draft from the lower levels
to the upper levels, with the magnitude of the draft influenced
by the height of the building, the degree of air-tightness of exterior
walls of the building, and temperature differential between inside
and outside air.6 This effect was particularly strong on the night
of the fire due to the cold outside temperature. Interior air leakage
rates, through shaft walls and openings, also modulate the rate
of air flow due to stack effect. Smoke and toxic gases become entrained
in this normal air movement during a fire and are carried upward,
entering shafts through loose building construction or pipe and
duct penetrations. The air flow carries smoke and gases to the upper
portions of the structure where the leakage is outward.
At the upper portions of the structure, smoke and toxic gases fill
the floors from the top floor down toward the fire, creating a dangerous
environment for building occupants and firefighters. During the
investigation of this fire, this upward flow was evidenced by the
presence of heavy soot in the 38th floor mechanical room and all
the upper floors of the building. The path of smoke travel to the
upper floors was vividly evidenced by the soot remnants in HVAC
shafts, utility chases, return air shafts, and exhaust ducts.
Fuel loading on the fire floors consisted mainly of files and papers
associated with securities trading and management consulting. At
least one floor had a significant load of computer and electronic
equipment. In some cases, correlation could be found between heavy
fuel load and damage to structural members in the affected area.
From the 22nd floor to the 29th floor, the fire consumed all available
combustible materials with the exception of a small area at the
east end of the 24th floor.
Structural Conditions Observed
Prior to deciding to evacuate the building, firefighters noticed
significant structural displacement occurring in the stair enclosures.
A command officer indicated that cracks large enough to place a
man’s fist through developed at one point. One of the granite
exterior wall panels on the east stair enclosure was dislodged by
the thermal expansion of the steel framing behind it. After the
fire, there was evident significant structural damage to horizontal
steel members and floor sections on most of the fire damaged floors.
Beams and girders sagged and twisted -- some as much as three feet
--under severe fire exposures, and fissures developed in the reinforced
concrete floor assemblies in many places. Despite this extraordinary
exposure, the columns continued to support their loads without obvious
Perhaps the most striking lesson
to be learned from the One Meridian Plaza high-rise fire is what
can happen when everything goes wrong. Major failures occurred in
nearly all fire protection systems. Each of these failures helped
produce a disaster. The responsibility for allowing these circumstances
to transpire can be widely shared, even by those not directly associated
with the events on and before February 23, 1991.
To prevent another disaster like One Meridian Plaza requires learning
the lessons it can provide. The consequences of this incident are
already being felt throughout the fire protection community. Major
code changes have already been enacted in Philadelphia (see Appendix
G) and new proposals are under consideration by the model code organizations.
These changes may eventually reduce the likelihood of such a disaster
in many communities.
|1.Automatic sprinklers should be the standard
level of protection in high-rise buildings.
property conservation and life safety record of sprinklers
is exemplary, particularly in high-rise buildings. While other
fire protection features have demonstrated their effectiveness
over time in limiting losses to life and property, automatic
sprinklers have proven to provide superior protection and
the highest reliability. Buildings in some of the nation’s
largest cities, designed and built around effective compartmentation,
have demonstrated varying success at containing fires, but
their effectiveness is often comprised by inadequate design
or installation and may not be effectively maintained for
the life of the building. Even with effective compartmentation,
a significant fire may endanger occupants and require a major
commitment of fire suppression personnel and equipment. Retrofitting
of automatic sprinklers in existing buildings has proven effective
in taking the place of other systems that have been found
to be inadequate.
2. Requirements for the installation of automatic
sprinklers are justified bv concerns about firefighter safetv
and public protection effectiveness. as well as traditional
measures such as life safety and property conservation.
The property protection value of sprinklers was recognized
long before life safety became a popular justification for
installing fire protection. Life safety has become the primary
concern in recent times, justifying the installation of automatic
sprinklers in high-rise buildings. The value of sprinklers
as a means of protecting firefighters has rarely been discussed.
Members of the fire service should promote automatic fire
sprinklers if for no other reason than to protect themselves.
Requiring the installation and maintenance of built-in fire
protection should become a life safety issue for firefighters.8
The opposition to retrofit protection has consistently cited
cost concerns. Communities need to be made aware that the
costs they defer may be paid by firefighters in terms of their
safety. This is above and beyond the potential loss to citizens
and businesses that is usually considered.
|3. Code assumptions about fire department standpipe
tactics moved invalid.
One of the principal code
assumptions affecting fire department operations at One Meridian
Plaza concerned the installation of standpipe pressure reducing
valves. The rationale for PRVs is the concern that firefighters
would be exposed to dangerous operating pressures and forces
Firefighters at One Meridian Plaza had great difficulty determining
how to improve flow and pressure from hose outlets during
the fire. Even if firefighters could have closely examined
the valves, with good light and under less stressful conditions,
it is unlikely that they would have been able to readjust
the valves. Numerical indicators on the valve stems represented
an index for adjustment not the actual discharge pressure.
(This may have confused the technicians responsible for installing
and maintaining the valves. Investigators found valves set
at “20” and “80” on the index markings.
To achieve 65 psi would have required a setting from 88 to
91 on the index. A setting of 150 to 158 was necessary to
produce the maximum allowable 100 psi.)
Pressure regulating devices come in three different types:
Pressure restricting devices which reduce pressure under
flowing conditions by reducing the cross-sectional area of
the hose outlet.
Pressure control valves are pilot-operated devices which
use water pressure within the system to modulate the position
of a spring-loaded diaphragm within the valve to reduce downstream
pressure under flowing and non-flowing conditions.
Pressure reducing valves use a spring-loaded valve assembly
to modulate the position of the valve disc in the waterway
to reduce the downstream pressure under flowing and non-flowing
Further differentiation within each of these types results
from differences in manufacturer specifications. (Details
are provided in the Philadelphia Fire Department fact sheet
on pressure regulating devices in Appendix G.) Some devices
are field adjustable, some are not. Some can be removed to
permit full, unrestricted flow, others cannot.
if they connected hose lines to outlets near the base of
standpipe risers of substantial height, particularly those
supplied by stationary fire pumps. For example, in a 275 foot
high standpipe zone (the highest permitted using standard
pipe and fittings), a pressure of 184 psi is required at the
base of the riser to overcome elevation and produce the minimum
required outlet pressure of 65 psi at the top of the riser.
At this pressure, a standard 2 1/2-inch fire hose fitted with
a 1 1/8-inch straight bore nozzle would produce a back pressure
(reaction force) in excess of 500 pounds. This is a well-founded
concern; however, it is built upon the assumption that fire
departments use 2 1/2-inch attack lines and straight bore
nozzles to attack fires from standpipes. Most fire departments
today use 1 3/4-inch and 2-inch hose with fog nozzles for
interior attack. These appliances require substantially greater
working pressures to achieve effective hose streams.
In the aftermath of this incident, the NFPA Technical Committee
on Standpipes has proposed a complete revision of NFPA 149
to more closely reflect current fire department operating
practices. Section 5-7 of the proposed standard requires a
minimum residual pressure of 150 psi at the required flow
rate from the topmost 2 1/2-inch hose outlet and 65 psi at
the topmost 1 1/2-inch outlet (presumably for occupant use).
Minimum flow rates of 500 gpm for the first standpipe and
250 gpm for each additional standpipe remain consistent with
past editions of the standard. The proposed new requirements
limit the installation of pressure regulating devices to situations
where static pressures at hose outlets exceed 100 psi for
occupant use hose or 175 psi for fire department use hose.
This will provide substantially greater flow and pressure
margins for fire department operations. These requirements
are intended to apply to new installations and are not retroactive.
|4. The requirements and procedures for design. installation.
inspection, testing. and maintenance of standpipes and oressure
reducing valves must be examined carefully.
proposed revision of NFPA 14 (1993) and a new NFPA document,
NFPA 25, Standard for the Installation, Testing, and Maintenance
of Water-Based Fire Protection Systems (1992), address many
of the concerns arising from this fire regarding installation
and adjustment of pressure reducing valves. NFPA 14 requires
acceptance tests to verify proper installation and adjustment
of these devices. NFPA 25 requires flow tests at five year
intervals to verify proper installation and adjustment.
The report of the Technical Committee on Standpipes appears
in the NFPA I992 Fall Meeting Technical Committee Reports,
Neither of these standards proposes changes in the performance
standards for the design of pressure reducing valves.
Standard performance criteria for the design and operation
of each type of valve should be adopted to encourage user-friendly
designs that will permit firefighters to achieve higher pressure
and flow rates without interrupting firefighting operations.
The operation and adjustment of valves should be easy to identify
and clearly understandable by inspection and maintenance personnel
without reliance on detailed operating or maintenance instructions.
It is extremely important to have all systems and devices
thoroughly inspected and tested at the time of installation
and retested on a regular basis. Fire suppression companies
that respond to a building should be familiar with equipment
that is installed in its fire protection systems and confident
that it will perform properly when needed.
|5. Inconsistencies between code assumptions and firefighting;
tactics must be addressed.
The inconsistency between
fire department tactics and design criteria for standpipe
hose outlet pressures was widely recognized before this fire.
However, little was done to change fire department tactics
or to amend the code requirements for standpipe installations.
Fire departments utilize lightweight hose and automatic nozzles
for the same reasons the code requires pressure reducing valves:
firefighter safety. The inconsistency between these approaches
can cause serious problems. Where pressure reducing valves
are not installed, fire departments can usually augment water
supplies by connecting to the fire department connections.
However, when contemporary firefighting tactics are employed
and improperly adjusted PRVs are installed, the combination
is likely to produce hose streams with little reach or effectiveness.
The PRV equipped hose outlets on the 22nd floor of One Meridian
Plaza, adjusted as reported at the time of the fire, would
have produced nozzle pressures of approximately 40 psi. This
is insufficient for a straight stream device and dangerously
inadequate for a fog nozzle.
Standard operating procedures for high-rise buildings, particularly
those not protected by automatic sprinklers, should reflect
the potential need to employ heavy firefighting streams, which
may require higher flows and pressures.
|6. Pre-fire planning is an essential fire department
The availability of information about
the building was a problem in this incident.
The purpose of conducting pre-fire plans is be to gather
information about buildings and occupancies from the perspective
that a fire will eventually occur in the occupancy. This information
should be used to evaluate fire department readiness and resource
capabilities. At a fire scene, pre-fire plan information can
be used to formulate strategies for dealing with the circumstances
which present themselves.
Pre-fire planning activities should identify building and
fire protection features which are likely to help or hinder
firefighting operations and record this information in a format
usable to firefighters at the scene of an emergency. Recognizing
and recording information about pressure restricting devices
and pressure reducing valves should be among the highest priorities.
Information on fire alarm systems and auxiliary features such
as elevator recall, fan control or shutdown, and door releases
should also be noted.
The Fire Department was unable to obtain important details
about the installed fire protection at One Meridian Plaza
during critical stages of the fire attack. Detailed information
about the design and installation of standpipes, pressure
relief valves and the fire pump, could have aided firefighters
significantly if it had been available earlier in the fire.
Pre-fire plans and standard operating procedures should also
consider evacuation procedures and plans for the removal of
|6-Occupants and central station operators must always treat
automatic fire alarms as though they were actual fires. especially
in high-rise buildings.
Building personnel, alarm services, and fire departments
must develop an expectation that an automatic alarm may be
an indication of an actual fire in progress. Automatic detection
systems have gained a reputation for unnecessary alarms in
many installations. This has caused an attitude of complacency
that can be fatal in responding to such alarms. To change
such attitudes and expectations, it will be necessary to improve
the reliability and performance of many systems.
By choosing to investigate and verify the alarm condition,
the building engineer nearly lost his life. If not for the
ability to communicate with the lobby guard to relay instructions
for manually recalling the elevator, this individual would
likely have shared the fate of his counterpart who died in
a service elevator at the First Interstate Bank Building Fire
in Los Angeles (May 4, 1988).
|7-Incomplete fire detection can create a false sense
Automatic fire detectors, like automatic
sprinklers, are components of engineered fire protection systems.
A little protection is not always better than none. Over-reliance
on incomplete protection may lead to a false sense of security
on the part of building owners and firefighters alike.
Automatic fire detectors can only notify building occupants
or supervisory personnel at a central, remote, or proprietary
station that an event has occurred, and in some cases initiate
action by other systems to limit the spread of fire, smoke,
or both. (In this case, automatic detectors initiated an alarm,
recalled elevators, and shutdown air handling equipment; however
an elevator was subsequently used to go to the fire floor
to investigate the alarm.)
Smoke detectors at One Meridian Plaza were installed in particular
areas as required by the 1981 amendments to the fire code;
that is at the point of access to exits, at the intakes to
return air shafts, and in elevator lobbies and corridors.
The apparent underlying logic was to protect the means of
egress and to detect smoke in the areas where it was most
likely to travel. It appears in this case that the partitions
and suspended ceiling contained the smoke and heat during
the fire’s incipient phase and prevented early detection.
In all likelihood, the first detector may not have activated
until after the room of origin had flashed-over. Shortly after
flashover, the suspended ceiling in this area probably failed
permitting the fire to spread throughout the return air plenum.
Once the fire broke the exterior windows and established an
exterior air supply there was little that could be done to
control the fire. Firefighters were disadvantaged by the delay
in reporting the fire.
|8-Nationally recognized elevator code requirements
for manual control of elevators during fire emergencies work.
Elevator control modifications at One Meridian
Plaza were accomplished in accordance with Commonwealth of
Pennsylvania requirements based on ANSI/ASME A17.1, Safety
Code for Elevators and Escalators. The elevators performed
as expected by the standard. The only problem with the elevator
response was the decision of the building engineer to override
the system to investigate the alarm
|9-The ignition source provided by oil-soaked rags
is a lone recognized hazard that continues to be a problem.
Had the contractor refinishing paneling on the
22nd floor not carelessly left oil soaked cleaning rags unattended
and unprotected in a vacant office, this fire would not have
occurred. To pinpoint the particular source of ignition of
this fire as the sole cause of the death and destruction that
followed is a gross oversimplification. Nevertheless, failure
to control this known hazard is the proximate cause of this
disaster. The danger of spontaneous heating of linseed oil-soaked
rag waste is widely recognized. Each model fire prevention
code requires precautions to prevent ignition of such materials.
At a minimum, waste awaiting removal from the building and
proper disposal must be stored in metal containers with tight-fitting,
self-closing lids. Leaving these materials unattended in a
vacant office over a weekend was an invitation to disaster.
This is both an education and an enforcement problem for fire
|10-Building security personnel should be vigilant
for fire safety as well as security threats, especially while
construction, demolition. alteration, or repair activities are
Earlier in the day, the building engineer
had become aware of an unusual odor on the 22nd floor which
he associated with the refinishing operations which were underway
there. When the alarm system activated later that evening
he first believed the solvent vapors had activated a smoke
The roving security guard made no mention of anything unusual
during his rounds of the fire area earlier in the evening.
It is conceivable that no detectable odor of smoke or audible
or visible signals of a fire were present when the guard last
checked the floor. However, a cursory check is not adequate
when construction, demolition, renovations, or repair activities
are underway in a building area. Fire hazards are often associated
with construction activities, and buildings are especially
vulnerable to fire during such operations. For these reasons,
it should be standard practice to check these areas even more
carefully and thoroughly than usual. All building operating
and security personnel should have basic training in fire
prevention and procedures to be followed when a fire occurs.
|11-Emergency electrical systems must be truly independent
Article 700 of the National Electrical
Code recognizes separate feeders as a means of supplying emergency
power. However, Section 700-12(d) requires these services
to be “widely separated electrically and physically...to
prevent the possibility of simultaneous interruption of supply.”
Installing the primary and secondary electrical risers in
a common enclosure led to their almost simultaneous failure
when the fire penetrated voids in the walls above the ceiling
of the 22nd floor electrical closet. The intense heat melted
conductor insulation resulting in dead shorts to ground which
opened the overcurrent protection on each service interrupting
power throughout the building.
Auxiliary emergency power capability was provided by a natural
gas powered generator located in the basement mechanical room.
This generator was intended to supply one elevator car in
each bank, fire pumps, emergency lighting and signs, and the
fire alarm system. However, this generator set failed to produce
power when needed. (Generator maintenance records indicated
a history of problems; however, the root cause or mechanism
responsible for these problems was not identified.)
Supplying the generator from the building natural gas service
also left the emergency power system vulnerable in the event
of simultaneous failure of the electrical and gas public utilities.
The transformers that provided power for the adjacent building
were installed in the basement of the One Meridian Plaza Building.
These transformers had to be shut down due to the accumulation
of water in the basement, resulting in the loss of power to
this building as well. As a result the elevators in the adjoining
building could not be used.
|12. The regulations governing fire-resistance ratings
for high-rise structural components should be re-evaluated.
The degree of structural damage produced during
the fire at One Meridian Plaza suggests that the requirements
for structural fire resistance should be reexamined. Floor
assemblies deflected as much as three feet in some places.
The fire burning on multiple floors may have produced simultaneous
exposure of both sides of these assemblies, which consisted
of concrete slabs on corrugated decks, supported by structural
steel beam and girder construction, sprayed with cementitious
fireproofing materials. The standard fire test for floor and
ceiling assemblies involves exposure from a single side only.
Columns and certain other structural elements are normally
exposed to fire from all sides. In this fire, the steel columns
retained their structural integrity and held their loads.
Experience in this and similar high-rise fires suggest that
columns are the least vulnerable structural members, due to
their mass and relatively short height between restraints
(floor to floor). Major damage has occurred to horizontal
members, without compromising the vertical supports.
|13. Features to limit exterior vertical fire spread
must be incorporated in the design of high-rise buildings.
Exterior vertical fire spread or autoexposure can be a significant
fire protection problem in construction of high-rise buildings
if interior fire growth is unrestricted. Because of the difficulty
with retrofitting exterior features to restrict fire spread,
the installation of automatic sprinklers to restrict fire
growth is the most simple approach to managing this risk in
existing buildings. Exterior features to prevent fire spread
must usually be designed and built into new buildings. Many
modem (international style) and post-modem building designs
present difficult exterior fire spread challenges because
of their smooth exterior facades and large glazing areas.
Variegated exterior facades and larger noncombustible spandrels
significantly reduce exterior fire spread effects by increasing
the distance radiant and conductive heat must travel to stress
exterior windows and to heat materials inside the windows
on floors above the fire.