3 in Elevator Die As Contents Blaze In Fire-Resistive New York Building
The fire at 919 Third Avenue in New York City last December 4 was not an instant replay of the fire at One New York Plaza a few months earlier as some reports indicated. This later fire occurred on the fifth floor, so that it was fought from ground level, and of even more importance is the fact that the Third Avenue building was constructed according to the building code adopted in 1968.
The building is a subbasement, basement and 47-story, fire-resistive skyscraper occupied principally by carpet manufacturers and wholesalers for display rooms. It was structurally completed last spring, but finishing work was still in progress on various floors for tenants who were just moving in. The basements and first six floors were of an irregular shape which can best be likened to a distorted T. The maximum dimensions of the first six floors were 233 X 208 feet. The tower section above the sixth floor was 225 X 115 feet.
The building had a reinforced concrete core containing stairs, elevators, utilities, and air-conditioning equipment, Steel beams and columns were protected by sprayed asbestos. Floors were of 4½-inch lightweight concrete on corrugated steel form units. The form units were not required to, and did not, have fireproofing on the underside. A hung ceiling of class 25 acoustical board was provided throughout the tenant area.
Exterior wall construction
The exterior walls were of panel construction with fixed windows. There were no masonry barriers at the outer walls to prevent vertical spread of fire, but the aluminum skin was tight against the edge of the concrete floor. Foil-backed fiber glass insulation was attached to the aluminum skin. There were two stairways arranged in scissor fashion in the tower section plus a separate stair tower at the east end for the six-story section. A fire tower is no longer required in New York City. Proper doors and enclosures were provided for stairs, utility rooms and shafts. There were three elevator banks that served floors 2 to 19, 19 to 33 and 33 to 47, as well as two service elevators that serviced all floors.
There were two independent airconditioning systems, one supplying the 2nd through 21st floors and the other, the 22nd through 47th floors. Fan rooms were on the 12th and 35th floors. Air was blown through vertical ducts at every fourth window opening to air handling units under the windows. These ducts were enclosed on each floor by gypsum board on steel stud partitions. Except for these vertical ducts, there were no other penetrations of the floor construction.
The interior sections of the building were fed air from two central supply shafts in the core via ducts to various openings in the hung ceiling. Return air passed into the plenum between the hung ceiling and the floor construction and thence to vertical return air shafts. All openings in the shafts were protected by shutters held open by fusible links. Since the new building code requires a fire separation between tenants of at least 1-hour rating, the plenum was subdivided by a continuation of the tenant wall, or partition, through the concealed space. Generally, separate ducts were run from the plenum above each tenant to the return air shaft.
Fire detectors for fans
Since corridors around the periphery of the core must have 1-hour rating, these corridors were supplied with fresh air from the interior air supply ducts, and this air was vented through the washrooms. All return air fans were equipped with thermal fire detectors and all supply air fans with smoke detectors. The basement and subbasement areas were protected with automatic sprinklers and all floors were equipped with two standpipes supplied by three tanks, having 3500 gallons reserved for standpipe use, two 750-gpm fire pumps and fire department connections.
About 18 floors of this building were used as carpet showrooms and the remainder as office occupancies. Carpets were displayed in many fashions, some hung on racks, others affixed to walls as a mural, most on inclined platforms, known in the trade as waterfalls, that contained 10 to 12 samples about 4X6 feet. The Aldon Carpet Company showrooms, where the fire started, was an area of about 7500 square feet on the north side of the fifth floor. There were several private offices in various sections containing the usual office furniture. The floor was covered with a wool rug with a thin foam rubber cushion underneath. Rugs were principally displayed on waterfalls throughout the area except for a few rugs on single racks in the northeast corner. Rugs on display were of wool, nylon, polyester and viscose pile, and some had latex glue or foam rubber backing.
The fire started in a small office at the south perimeter of the Aldon space which was being used temporarily for storage of some paper supplies, carpet swatches, felt padding and scrap from the office installation.
Cutting torch blamed
Reports of witnesses and official investigations indicate that the fire was started at about 9:50 a.m. by sparks from a cutting torch that was being used to remove steel angles at the ceiling. The fire was discovered very shortly after ignition and the fire department was called at once. It is reported that when the fire was first noticed, it was a relatively small blaze near the floor. But by the time an employee ran to his office to call the fire department and then returned to the fire area, it was impossible to get close to the office that was afire. The fire spread from this office to the rugs on display, which burned readily because of the combustible backing and pile.
Building employees and construction workers became aware of the fire as it developed, so that notification was given, via telephone and walkietalkies, to the building operators, construction men and elevator starters. After the fire department was called, an attempt was made to fight the fire with standpipe hose, but the men were soon driven from the fire area by smoke.
Meanwhile, a building engineer heard of the fire via his walkie-talkie. He immediately shut down all fans serving the lower part of the building but shortly afterwards, on instruction, restarted the return air fans and arranged the dampers to dump all the return air to the outside.
Elevator passengers rescued
The fire department responded promptly and rescued a number of persons trapped in elevators at the fire floor. Outside heavy-caliber lines from ladder trucks were used to knock down the fire and three inside lines from the standpipe were used for final extinguishment and cleanup. The fire was controlled in about 35 minutes.
The blaze itself was pretty well confined by the fire partition to the area occupied by the Aldon Carpet Company. However, the entire contents of this space were destroyed but not completely consumed by the flames. The heat caused the aluminum spandrel walls to expand and pull away from the floor slab, thereby allowing heat to pass to the sixth floor. However, only a small section of rug on that floor was burnt.
Once again, sprayed asbestos failed to protect several beams. Distortion took place and the connecting bolts at the girder were sheared off. A large number of sixth floor concrete panels which were damaged required replacement, probably because of the lack of reinforcing bars. Windows also were blown out by the fire, as well as broken by fire fighters.
Smoke spread throughout the building, causing some damage to various tenants. The total property damage to building and contents is estimated at about $2.5 million.
The Fire Patrol did a superb job protecting the display rooms under the fire area. While fire fighters were putting out the fire on the fifth floor, the patrol was working on the floors underneath. Rolled salvage covers were used to block doorways and office entrances to prevent water from running in. More than 100 covers, 12 X 18 feet, were neatly spread over the carpet displays on the fourth floor. Catch basins were formed with other covers to that the water could be pumped to drain outlets. Despite the fact that 1500 gpm of water was pouring into the fire area that Friday morning, the patrol activities made it possible for the display area on the fourth floor to be open for business the following Monday morning.
Lack of fire towers
The problem of life safety is once again evident in high-rise buildings. Despite the urging of the New York Board of Fire Underwriters to have requirements for fire towers retained in the city’s new building code, this important safeguard was dropped. Employees on upper floors became panic stricken when smoke seeped into their offices and they were unable to open windows to get fresh air. The fire tower would have provided them with an access to the fresh air and safety that they desperately desired.
The experience of the tenants in this building shows some of the problems in evacuation of a high-rise structure. When employees left the fifth floor via the central stair tower about 10 minutes after the start of the fire, one of the employees stopped at the fourth floor to warn tenants. He found that there was already considerable smoke on that floor and the occupants were leaving via the stairs.
Employees on the 11th floor noticed smoke coming from the wall and ceiling air-conditioning outlets and immediately took an elevator. The elevator stopped at the seventh and fifth
(fire) floors despite the fact that the occupants reported that they did not push these floor buttons. Fortunately, the Firemen had just arrived and escorted the passengers through the smoke to the stairs. Occupants of the lower 19 floors were subjected to severe smoke conditions and those that used the central stair tower found the smoke unbearable at about the 8th floor. A group had to return up the stairs to the 14th floor, where the first open door was found. Smoke on this floor was sufficiently dense so that windows were broken with chairs to
get fresh air.Smoke was probably carried throughout the lower half of the building through stairs, elevator shafts and air supply ducts.
Above the 22nd floor, conditions were much better because of the separate air-conditioning system. In general, these offices were free of smoke, but the corridor around the center core was charged with some smoke. This was probably carried up by chimney action through the stairs and service elevator shafts. Employees who used the stairs found them untenable at about the 33rd floor and reversed their travel to go up to the roof. Those who took elevators to the first floor had no difficulty because the elevators had no openings to the fire floor and were essentially smoke-free.
Elevator causes deaths
Three construction workers were found dead on the fifth floor by fire fighters. They were in an elevator that stopped, or was stopped, on the fifth floor shortly after the firemen rescued the trapped group from the 11th floor. These victims were met by a blast of heat and smoke when the door opened. One man was found in the elevator and the other two in the corridor, where they were overcome. At least 20 other persons were injured or overcome by smoke.
The value of many features of the new building code was demonstrated during this fire. The wisdom of providing fire separations was evidenced by the absence of damage by heat and flames in the tenant areas adjoining the west end of the Aldon Carpet area. The floors had no electrical or communication wiring passing through them to spread the fire. The enclosure and fire-stopping of the vertical airconditioning ducts successfully prevented any vertical heat transmission. Openings from these vertical ducts served only one floor, thereby eliminating a hazard created by flexible connectors piercing a floor. The insulation on the outer wall was noncombustible and did not spread the fire. Fire detection and automatic controls were not tested because of prompt detection of the fire and the manual operation of the air-conditioning system.
The following suggestions are made for improving fire safety in this type of building:
- The requirement for fire towers should be reinstated in the New York City building code. Fire towers have provided safe egress for over 50 years in New York City skyscrapers and their need is even greater now because of the absence of operable windows and the presence of air-conditioning systems.
- Vertical separation of windows by fire-resistive construction should be provided to prevent transmission of fire through the space between the outer skin and the edge of the floor slab. If this fire had occurred on one of the upper floors, this lack of vertical protection could have been a serious factor in spreading fire to the upper floors.
- Automatic sprinkler protection should be provided to protect combustible occupancies. It is of interest to note that a large segment of the carpet industry moved from a fire-resistive, sprinklered building to this new unsprinklered edifice.
- Consideration should be given in the design of a fire-resistive building to the degree of damage that will be caused by a small fire. An assembly or method of construction should not only prevent transmission of fire and successfully support the design load for its rated period of time, but also resist a small fire or a fire of short duration without sustaining damage requiring the replacement of floor construction or structural members.
- Means should be provided for venting a fire floor to prevent the spread of smoke throughout the building. This venting should preferably be directly to the outside or through separate shafts not used by personnel. Such venting should be in accordance with the capabilities and design of the air-conditioning system, and proper controls should be provided for use under fire conditions.
- Pre-fire plans should be prepared for all buildings in conjunction with the fire department to assure that persons on floors above the fire have a usable means of egress. Means should be provided to notify ail employees of an emergency and the action to be taken by them. The chief complaint of employees on upper floors was the lack of notification of fire.
- Elevator call buttons should not be responsive to heat, smoke or flames.
- Openings around pipes, conduits, etc., through fire walls and partitions should be properly fire-stopped.