WINTER OPERATIONS
BY BOB PRESSLER
Proper investigation at a seemingly routine response and the subsequent actions taken averted a tragedy at a supermarket in Jersey City, New Jersey, on January 9, 1996. At 10 a.m., an emergency call was received for a report of a collapsed ceiling at the Twin City supermarket. An investigation by first-arriving units showed that several tiles of a suspended ceiling had dropped out of their grid because, it was discovered on further investigation, the front wall had started to pull away from the rest of the building. Several of the two- by 10-inch rafters that formed the hip section at the front wall of the bowstring truss assembly had been pulled out of their resting places. The first truss in from the front of the building also had been affected. In the area where the truss sections were bolted together, a large crack was now visible.
The building involved was a large, one-story structure approximately 80 feet wide by 220 feet deep with masonry exterior walls and a heavy timber bowstring truss roof assembly. The front wall had a large parapet that varied in height but was highest in the middle, approximately two stories high. Recent snowfalls had covered the region with more than two feet of snow. Blowing and drifting snow, coupled with snow sliding down from the rooftop, had formed drifts in the valley near the front wall against the parapet, up to an estimated seven to eight feet in depth.
One cubic foot of snow weighs approximately 12 pounds. Sections of the roof/ parapet wall area had eight feet of snow, resulting in an approximate 96-pound-per-square-foot load on the front portions of the structure. Flat roofs routinely will withstand 30-pound-per-square-foot loads, so the snow load was seriously straining the building.
The IC immediately ordered all employees and shoppers to vacate the building, including some workers attempting to shovel off the roof areas. He also requested the response of the building department and an engineer to determine building stability and what repairs were needed to make the building habitable again. The area was roped off and, after the arrival of the building department, the incident was concluded as far as the fire department was concerned.
COLLAPSE
At approximately 4 p.m., the Jersey City central office received reports of a building collapse at Sip and Romaine avenues, the site of the previous response. A full first-alarm assignment of three engine companies, two truck companies, a heavy rescue, one battalion chief, and the on-duty deputy chief responded. The safety officer, hearing the dispatch, also responded. First-arriving units were met with an almost complete collapse of the supermarket`s front wall, which had occurred in conjunction with the failure of the hip section and the cracked bowstring truss. The collapsed wall covered the entire sidewalk area in front of the store and had crushed three parked cars at the curb. Debris had landed in the street, covering an area of 25 to 30 feet from the building front. Although the building had been vacated that morning, eyewitnesses reported people in the area in front of the building just prior to the collapse: Two women had been standing just outside the barricaded area when the collapse occurred, and an elderly woman was reported to have just crossed the street into the area in front of the building. The two women were immediately accounted for–uninjured but noticeably upset. The older woman was feared to be under the debris.
On arrival of the deputy chief, an additional truck company and squad company were special-called, followed by the transmission of a second alarm for manpower.
The first priority was checking with the witnesses for any information on passersby. This helped account for the two women who had just missed getting hit by the front wall and also directed the rescuers to the area where the elderly woman was feared trapped. A rapid check of the surface debris revealed no apparent victims.
Operations were next directed toward the crushed cars at the curb and a visual check of any accessible voids. The cars were crushed almost flat, so checking them for occupants required extensive hand-digging. As members started select debris removal in the areas around the cars and where the elderly woman was last seen, other members worked to uncover any hidden voids. Snow covered most of the area near the storefront, so snow shoveling was required for access to the store itself. Large sections of the masonry front wall were broken into smaller sections to facilitate removal.
Some of the tools used to help in debris removal included demolition hammers, electric jackhammers, and air chisels–all carried on the fire department`s heavy rescue. The Water Department responded with an air compressor and jackhammer, and Public Service Gas and Electric sent a payloader to assist. Firefighters used an assortment of hand tools, including a rotary saw, a thermal imaging camera for initial searches of unaccessible voids, and shovels. After they broke up pieces of debris, they removed the pieces by hand and passed them toward the street.
Digging continued until the cars were exposed, for access to both the interior and the area around and under the cars. The area where the elderly woman was last seen by witnesses was cleared down to sidewalk level by hand, but no victim was found. It was later determined that the woman had turned away from the building`s front just prior to the collapse.
After the hand-digging had exposed all areas where people might have been trapped and would have survived the collapse, the payloader was brought in for general debris removal. The debris was brought out and dumped in the street, where it was searched further for victims–all searches proved negative.
Winter operations require that operating forces be relieved at frequent intervals. Members must be removed to a local fire station, a school, or other heated areas so they can warm up. Sometimes departments use buses supplied by local companies for this purpose. If no suitable arrangement is possible, companies should be relieved and returned to their stations for rehab while relief crews continue operations. n
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Members work in the area around one of the three crushed cars. Debris was removed from the tops of the cars to give access to the interior. The debris also was removed from the sides of the vehicles to expose the area under the vehicles. This area was checked in case any passersby were driven under the cars by the force of the collapsing wall. (Photos by Joe Lovero.)
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A firefighter checks an existing void at the rear of one of the crushed cars. This void gave him access to the area underneath the car.
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Sliding snow obscured the front of the supermarket. The snow had to be shoveled by hand to gain access to the store interior and the area in front of the store. Note the top of the bowstring truss at the top of the photo. The area still covered with snow is comprised of the collapsed hip area of the roof and the remains of the first heavy timber truss.
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This overview of the area shows the distance the debris traveled. The view is from the street side of the parked cars, one of which is under the pile of bricks behind the firefighter.
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Select debris removal. Firefighters formed a chain and removed debris piece by piece to the street. In the foreground, a firefighter uses an air gun to break a section of brick wall so it can be removed to the street. Spare bottles for the air-driven tool were brought and staged to limit downtime. The saw is at hand to cut through any metal found in the debris, such as conduit, ductwork, and ceiling grids.
BOB PRESSLER, a 22-year veteran of the fire service, is a firefighter with Rescue Company No. 3 of the City of New York (NY) Fire Department. He created and produced the video Peaked-Roof Ventilation for the Fire Engineering video series “Bread and Butter” Operations. Pressler has an associate`s degree in fire protection engineering from Oklahoma State University, is a frequent instructor on a wide range of fire service topics, and is a member of a volunteer department.
