Fire Fighting Problems In High-Rise Buildings
The two greatest life-safety problems in high-rise buildings are the combustible contents and the evacuation of occupants, according to speakers heard at a symposium on “Fire Problems in the Modern Building” conducted at Jersey City, N.J., State College on April 17.
High-rise buildings are loaded with combustible contents and interior finishing materials that give off smoke and toxic gases which take lives at “apparently great distances from the fire,” Chief Joseph M. Redden of the Newark, N.J., Fire Department told the symposium. He said that the interior finishes applied for attractiveness “can be likened to the construction of a frame building within a fire-resistive building.”
Other speakers urged the use of elevators to remove building occupants or the use of the areas of refuge where occupants could wait in safety until the fire was extinguished.
“It is unreasonable to expect people to walk out of a 60-story building. It just can’t be done,” said Walter M. Haessler, a fire protection engineer with Rolf Jensen & Associates. He explained that stairs “produce an unacceptable evacuation time.”
Both Haessler and Irwin Benjamin, chief of the fire research section of the building research division of the National Bureau of Standards, suggested refuge areas that could be kept smokefree and insulated from heat. Benjamin said that smoke could be kept out of a refuge area by increasing the air pressure in that area, and Haessler proposed dividing each floor into two fire areas so that the uninvolved one could be used by floor occupants during a fire and the use of stairs could be eliminated.
Benjamin urged that stair shafts be kept smoke-free—either by air pressure or by smoke towers. He commented that 2 1/2 to 3 minutes is the maximum time allowable for evacuating a building. Although total evacuation is still the primary concept, Benjamin added, it is all right only for low and mediumheight buildings.
In urging the use of elevators for removing high-rise building occupants, Benjamin voiced the opinion that they can be used safely in a time of emergency and that people are going to use them anyway. At the same time, he disclosed that tests in Washington, D.C., showed that the use of a cigarette lighter with certain call buttons would bring an elevator to a floor.
Elevators—not stairs—declared Richard Patton, a fire protection engineer and president of Patton Fire Protection and Research, Inc., provide the practical system for evacuation of a building. Along this same line, Haessler called for the provision of emergency power to at least two elevators in a building and asked why fire fighters should not be given the opportunity to climb stairs in a high-rise without facing a mob leaving by the stairs.
Contents fire problem
Declaring that the 1860s concept of inherently fire-safe building is “as wrong today as it was in the 1860s,” Patton explained that probably 90 percent of the life problem in buildings is associated with contents and that because we ignore the contents, our structural fire systems fail to save lives.
“For 100 years we have been trying to build an inherently fire-safe building,” Patton said, “but this is an impossible task because of the contents.”
He maintained that the solution to the problem is to “develop methods of suppressing the contents fire” by using modern knowledge. He charged that sprinklers developed to save buildings have not been aimed at saving lives.
“When we control the contents fire,” Patton said, “we control the structural fire,” and the result is the protection of lives.
The problems created by smoke in high-rise buildings were described by Redden, who pointed out that neither elevator shafts nor stair shafts are smoke-tight in these buildings.
Because of heavy smoke in a highrise, the Newark chief said, “it is a most difficult job for an officer to determine the exact location of a fire.” He added that fire fighters must be sent to reassure persons above a fire who are getting smoke but who are not endangered to prevent them from jamming the stairs.
The chief also pointed out that the “heat generated makes it impossible for fire fighters to operate on the fire floor except for brief periods of time.” This necessitates frequent exchanges of manpower.
Complete, supervised, automatic extinguishing systems could alleviate these problems, Redden told the symposium, adding that such systems are a rarity.
One way to handle the smoke problem is to maintain a positive pressure in areas around the fire floor, suggested Richard G. Gewain, research engineer and senior fire protection engineer for the American Iron and Steel Institute in New York City. A positive pressure, he explained, keeps smoke from moving to protected areas.
Gewain also suggested that a separate duct system be installed to remove smoke from any fire area. A positive system to remove smoke is needed, he said, because of stack effect in high-rise buildings. He explained that if it is cold outside, opening lower floor windows will not only admit air, but also will cause smoke to go up in the building as the cold air enters the structure.
When air handling system fans are shut down, he continued, heat and smoke will go to other parts of a building unless there is some means provided for handling smoke. He pointed out that the air-handling system in both the World Trade Center in New York and the Sears Building in Chicago, when completed, will be capable of exhausting smoke from these buildings.
Control the contents fire
In another view of the problem, Patton declared that there is no economically attractive way of controlling smoke except by controlling the contents fire.
“Controlling the smoke without controlling the contents fire is a fantasy. It is not a solution,” Patton maintained. “The solution is to put the fire out.”
Patton urged the installation of economical sprinkler systems specifically designed to save lives.
Building vestibules at floor entrances to stair wells and placing standpipes in these vestibules was proposed by Gewain. He explained that when fire fighters connect a hose to the standpipe on the fire floor, the vestibule door to the stairs could be kept closed to keep smoke from entering the stair shaft while the door to the floor was kept open by the hose line.
Redden cited the delay in sounding interior building alarms—or even the lack of any fire alarm system. Often the first indication of fire that occupants get is smoke, and this leads to “irrational acts and disaster,” the Newark chief commented.
In discussing this subject, Benjamin said that, in general, people die “because they did not get an adequate alarm” in time, and smoke is generally the cause of death. He urged the use of selective alarm systems in high-rise buildings and a communications control center at the entrance lobby for fire department use and for informing occupants of conditions in the building.
“We also suggest,” the National Bureau of Standards scientist added, “that a building alarm system be connected to a central alarm system.”
In his talk, Haessler said that there is often delay in the detection of highrise fires and this poor alarm record has allowed fire to grow too big for human survival.
One of the problems in selecting interior finishes, two speakers indicated, is the lack of realistic testing of materials. Gewain charged that the tunnel tests now conducted show only the relative reaction of materials to a fire, not how specific materials will react in a fire. He urged full-scale tests, not laboratory tests, which he maintained “do not give you the answers to how materials will act in the field.”
Benjamin viewed testing methods for interior finishes as “at best, a model,” and remarked that the testing may not resemble anything in real life.
In another view of the fire problem in high-rise buildings, Haessler questioned the adequacy of standpipe systems.
“We still fail to give fire departments enough water to fight the fire,” he declared.
He said that standpipes should be designed to provide fire fighters with the same water supply in the building that they have on the street.
In reply to a question about the need to provide fire protection in highrise buildings to save lives, Patton summed up the problem by replying that the argument for saving lives is not enough.
“You’ve got to make it economically feasible to provide fire protection in a building,” he said.
The high-rise symposium program was directed by Dr. Robert Kahrmann of the Center for Occupational Education at Jersey City State College. In addition to the center, sponsors were the New York Chapter of the Society of Fire Protection Engineers, and the Building Officials Association of New Jersey and the New Jersey Fire Prevention Association.