Collapse Rescue Operations

Photo by Tim Klett.

Collapse Rescue Operations

STRATEGY & TACTICS

A study of one of the most dangerous tasks a firefighter will ever perform.

“WOW! CAPTAIN, look at that building—the whole side of it collapsed!” the driver of the rescue company exclaims as the heavy-rescue truck nears the collapse scene.

The officer speaks into the apparatus radio handset. “Rescue to Communications Center, we have a major collapse of a six-story building, 25 by 85 feet, brick-and-joist construction. The exposure number four wall, floors, and roof have collapsed on top of cars in an adjacent parking lot.”

Outside of the apparatus, the officer of the rescue company sees the firstarriving engine company stretching a hoseline to the collapse area; the ladder company is taking two people off of a front window ledge. The stairway has collapsed with the floors.

Sizing up the collapse, the rescue officer looks up at the gaping hole that exposes most of the interior of the office building. The roof and top three floors have pancaked down on top of the cars as a result of a bearing wall failure. Near the front of the collapsed building, sections of the roof and floors are hanging down at a dangerous 60degree angle, an unsupported lean-to collapse. At the rear of the collapse, large metal shelving loaded with boxes and loose floor timbers threatens to tumble down on the pile of rubble. Everything appears about to collapse down on top of the area where the firefighters must search for victims.

There is no sign of fire—yet. However, if leaking gas from a broken gas pipe is ignited by a sparking electric wire, there will be an explosion. The firefighters must work fast.

Geared up in the street, the captain of the rescue company gives assignments to his firefighters. “John and I are going to search the collapse pile on the exposure four side.” Pointing to the remaining three firefighters, he says, “You take the front of the building; you take the exposure 2 side; you take exposure 3 side. Look for any surface victims who might be in shock or injured, and search all the voids you can find. Report back to me when you complete the search. Let’s go.”

The firefighters split up. The captain and firefighter climb up on top of the pile of collapse rubble, looking for persons lying in the debris. The two men step over shelving, boxes, broken timbers, and bricks. The late afternoon sunlight casts shadows beneath sections of collapsed floors and roof. They bend over and shine their lights into the dark spaces where bodies could be wedged. They call out into the smaller voids, “Anyone in there?”; they crawl in and out of the larger spaces. The officer looks up at the 60-foot-high, free-standing wall, at the remaining floors and shelving that could collapse down at any moment.

The firefighter shines his light into a large void created by a lean-to of the third and fourth floors, and hears something. “Help,” a weak voice calls out. “I’m trapped.” The firefighter turns to his officer and shouts, “Say, Captain, I found someone! I’m going in to get him!”

The officer scrambles over the rubble to where the firefighter is tying a search rope to a timber and is about to play it out before crawling into the dark space between the two partially collapsed floors. Just then, a section of metal shelving and several cardboard boxes tumble down from the upper floors into the parking lot. It misses them.

Inside the void, the firefighter gropes his way toward the trapped man’s voice. He lies on his back, moving sideways in a sliding motion, stepping across desks and boxes caught between the two collapsed floors. He is at a 45-degree angle. The space gets narrower. His flashlight suddenly goes out. He taps it with the hand holding the search line, and it blinks back on.

With his next step, something gives way suddenly, and the firefighter slides down between the two floors. His feet are stuck—he is wedged between the lean-to floors at the point where they meet. He drops the rope and, grasping the floor above him, looks for a handhold to pull himself up. Finally he finds one and pulls his body up, freeing his legs.

He is reminded of the house of horrors at the amusement park. There, too, the walls and floors were at crazy angles. You had to brace your arms and legs against a wall just to move forward. …

“Over here!” The man’s voice is below him.

Scanning the area in front of him with his flashlight, the firefighter can barely make out the form of the man. The victim is lying at a 45-degree angle, upside down, covered with plaster dust. His legs are pinned above his head. Several crushed cardboard boxes cover his feet.

“Please, get me out of here before both of us are buried!”

Quickly, the firefighter braces one leg against the floor beam above and, with both hands, starts pulling the boxes away from the man’s legs. Suddenly, there is a loud crack—a section of the floor above them slides downward several inches. The firefighter freezes. He hears his own heart pounding and feels the cold sweat on his forehead.

“Hurry!” the trapped man cries. “Don’t stop!” The firefighter uses a pocket knife to cut the last crushed box holding the man’s leg, pulls out the stuffing from within the box, and pulls the man’s leg free. The man tumbles down and then uprights himself inside the small space. The firefighter drops his flashlight. It rolls out of sight. He says, “Let’s go.” The two men start to crawl out of the dark space.

The firefighter leads the way, looking for the light of the void opening, but there is only darkness. The firefighter panics. “Hey, Captain, where are you?” he shouts. There is no response.

A sudden, loud crunching sound fills the dark void. The firefighter and victim, lying side-by-side on their backs at a 45-degree angle, hands and feet wedged against the collapsed floor section above them, feel the floor section sink down several inches, reducing the space they are lying in. “Oh, God!” the firefighter thinks to himself. “We are trapped!”

“John, John!” The voice of the captain is coming from somewhere above them. “The opening is over here! See my light!” Looking up, they can see beams of light poking through the cracks in the mountain of rubble. They must have somehow slid below the opening.

The firefighter and man start to climb upward. Cardboard boxes and dust start to fall on top of them. The firefighter climbs on top of an overturned metal desk, sees the void opening, and helps the victim up onto the desk and out of the rubble.

Crawling out into the fresh air, covered with dust, the officer and firefighter help the man off the collapse pile. “Great job,” the captain says to the firefighter as they reach the sidewalk.

QUESTION 1: Which one of the following are the steps of a collapse rescue plan?

1. Site survey or reconnaissance; selected debris removal; general debris removal.
2. Site survey or reconnaissance; surface search; void search.
3. Site survey or reconnaissance, surface search, void search, selected debris removal, general debris removal.
4. Site survey or reconnaissance, surface search, void search, selected debris removal.

QUESTION 2: Which of the following is an incorrect answer?

1. Site survey is the most productive lifesaving stage of a collapse rescue plan.
2. The gas should be the first utility shut off at a collapse.
3. The most dangerous stages of a collapse rescue plan are the site survey, surface search of the collapse rubble pile, and the void search.
4. Secondary collapse, explosion, and fire are the three greatest dangers at a collapse operation.

ANSWER TO QUESTION 1: The correct answer is C. The steps of a collapse rescue plan are survey of the collapse site, reconnaissance; surface search of the collapse rubble pile; the search of all voids; the selected debris removal (tunneling/trenching) to specific locations where people are suspected to be buried; and, finally, general debris removal.

ANSWER TO QUESTION 2: Answer A is incomplete and is thus the right choice. The most productive stages of a collapse rescue plan are the first three stages: site survey, the surface search of the collapse rubble pile, and the void search—not just the site survey or reconnaissance. Choices B, C, and D are accurate statements.

At 1503 hours on October 24, 1988, a six-story building collapsed. The structure, at 24 West 31st Street in New York City, was under renovation. The bearing wall on the exposure #4 side caved in. It fell in a curtain-fall collapse, triggering the pancake collapse of the three top floors down on top of cars in an adjacent parking lot. Sections of the collapsed floors and roof remained hanging in an unsupported lean-to configuration, and could have collapsed down on top of rescue workers at any moment during the entire collapse rescue operation.

Firefighters removed two people, about to jump from window ledges at the front of the building, with an aerial platform. Police and firefighters there extricated two victims trapped inside voids. Nine hours later, firefighters dug out a woman —alive—from beneath tons of collapse rubble.

According to the American Society of Civil Engineering, there are 500 major building collapses in the United States each year. The fire service is called to most of these structural failures to rescue people trapped in the collapse rubble.

When a fire department responds to a collapse, the chief must have a collapse rescue plan to put into operation, and he must establish an incident command system to coordinate actions effectively with other agencies. However, the individual firefighter who is ordered to climb up on the collapse rubble pile to search for and rescue trapped people must understand the dangers that threaten him during the collapse rescue operation.

This article will examine the dangers of a collapse rescue operation, one of the most deadly tasks a firefighter will ever be called upon to perform. All of the following dangers we are about to examine were present at the collapse rescue operation which occurred in New York City on October 24, 1988.

SECONDARY COLLAPSE

A secondary collapse of a partially destroyed floor or wall during a rescue operation can kill more firefighters than victims already buried in the collapse nibble. It is the greatest danger at a collapse of a multistory building.

Upon arrival at a building collapse, the rescue plan is: 1. Conduct a survey of all sides of the collapse for injured victims. 2. Search the rubble pile for surface victims. 3. Search all voids and spaces in the collapse rubble. 4. Selected debris removal, tunnel or trench to specific locations for buried trapped victims. 5. General debris removal. Steps one, two, and three of the collapse rescue plan —site survey, surface search, and void search—are the most productive. Most victims are rescued during these stages, but they are the most dangerous to the rescue workers. A second collapse of an unstable wall or floor of a multistory building could bury firefighters beneath tons of brick and timber, or trap them inside voids they are searching.

During the initial rescue operation, the collapse structure continues to shift and settle. So far at collapse rescue operations, the fire service has been fortunate. No firefighters have been killed during site survey, surface search, or void search. The cost (danger to firefighters)/benefit (number of victims discovered) relationship of this operation is still on the side of the fire service. Although it is an extremely dangerous task for firefighters to climb up on a collapse rubble pile and search for unconscious and trapped victims, it has always proven to be the most productive lifesaving action of the entire collapse rescue plan.

If, after completion of surface and void search, there is danger of a secondary collapse, all firefighters engaged in rescue work should be withdrawn from the collapse area (though fire extinguishing efforts may have to continue if there is a spreading fire) and a conference held. A safety analysis and reevaluation of the collapse site must be conducted by the incident commander. In the majority of cases, most of the victims will have been rescued by this, time. This conference should address: rescue worker safety, and the precautions that will be followed to safeguard them; the names and probable locations of persons still reported missing; and the procedure for selected debris removal-tunneling or trenching.

Because the chances of survival for victims found under the rubble during the next (latter) stages of the collapse rescue plan is less, greater safety precautions should be taken to protect the firefighters/rescue workers. Unstable walls might have to be removed. Shoring of partially collapsed structures may be in order. Lights may have to be set up during nighttime rescue work. Confirmation of gas, electric, and water shutoff must be obtained.

Rescue work must not stop as long as any person is still reported missing. People have survived, trapped inside voids beneath tons of collapse rubble, for several days. (An adult survived nine days and an infant, eleven days.) A buried victim’s chances for survival are highest if extricated from a collapse building within the first twenty-four hours. However, greater safety precautions must be taken to protect rescue workers during the selected debris removal operation.

EXPLOSION

The second greatest danger to a firefighter performing collapse rescue work is explosion. When a building collapses, a gas main can rupture, gas pipes break, gas cylinders inside the structure are often crushed and broken. There will be leaking gas. As the gas—natural or liquified petroleum—seeps throughout the collapse rubble, it will inevitably contact a snapped or broken, sparking electric wire or a flame from a heating or cooking appliance, and explode violently. The shock waves created by this explosion can cause a secondary collapse, killing many rescue workers who are doggedly working on and within the collapse rubble pile to remove victims. It will also collapse any voids where people might be trapped—and might have survived had it not been for rapidly spreading, gas-fed fire.

Leaking gas, even if it becomes too rich a mixture to ignite with air, can displace the oxygen inside of voids or in below-grade areas, killing victims and firefighters inside these confined spaces.

One of the most important assignments to be given by the officer in command of a collapse is to shut off the building services, such as gas, electricity, and water. The utility companies must be called to the scene; however, firefighters should be assigned to this task before they arrive. Utility companies are often delayed when responding at night or on weekends.

The gas should be the first utility shut off because it is the most dangerous during a collapse rescue operation. The first firefighters on the scene who are ordered to conduct the initial site survey, surface search, and void search must be on guard to detect the odor of leaking gas. The officer in command of the operation must be notified of the presence of gas. If there is a largediameter broken gas main and gas permeates the entire collapse site, firefighters must be withdrawn after the surface search is completed. The void search must be delayed until the main is shut off. Ideally, utility shut-off should be the second priority stage in the rescue operation, after site survey.

Utility shut-off takes some time to accomplish, so it should be started as soon as possible. Shut-off is usually completed during the void search. This vital procedure must be completed before tunnelling or trenching operations begin.

FIRE

The third greatest danger to rescue workers at a collapse site is fire. If a fire occurs during the collapse rescue operation involving a brick-and-joist or wood-frame building, it will spread rapidly. Firefighters searching for victims on top of the collapse rubble pile or inside voids may be trapped by the rapidly spreading flames. The fire could be fueled by flammable liquids leaking from crushed containers or machinery.

Also increasing the rate of flame spread on the rubble pile will be broken pieces of wood of the collapsed structure. After a collapse, large timbers are broken into smaller sections of wood. Air spaces and voids will honeycomb the collapse rubble pile around this splintered wood. Plaster and fire-retarding surface coverings will have been broken away from wood lath sections of walls and ceilings. As the fire protection engineers say, the ratio of exposed surface area to the total volume of wood is increased manyfold by the collapse. The two factors that increase the rate of burning—air and exposed wood surface-will be present at a collapse site.

The first engine company to arrive at a collapse must stretch a hoseline and protect against a fire and rapid flame spread. An aerial ladder pipe or aerial platform master stream should also be positioned near the collapse site. This aerial device should be supplied with a hoseline and be ready to extinguish a fire in the collapse rubble should it occur.

Firefighters must wear full protective clothing when conducting a surface search or void search. The chances of the collapse pile turning into a giant pyre are great. An explosion or flash fire could trap firefighters on top of the pile of broken wood. Firefighters will not be able to quickly climb down from a collapse rubble pile. The surface of jagged metal, broken timbers, bricks, holes on top of a collapse rubble pile will cause firefighters to trip and fall. Rescue workers should be equipped with clothing to protect themselves from flames and heat before they participate in the collapse rescue operation.

ELECTRICITY

A building has hundreds of feet of electric wire snaked throughout its walls, floors, and attic space. When a building collapses, this electric wire is threaded throughout the collapse rubble, just waiting to entangle an unsuspecting firefighter or his metal tool. Sparks from the wires can ignite small fires in nearby combustible debris.

Water pipes are also broken during a collapse, and, if there is a fire after the structural failure, fire department hose streams will be used. Water-soaked collapse rubble and exposed, broken, live electric wires, together with firefighters using metal tools for cutting, pulling apart debris, and digging out buried victims, create the possibility of serious injury or death by electrocution.

Photo by Ed Heavey.

If the collapse structure is of lightweight steel construction, the entire structure could be electrified, preventing the most productive lifesaving stages of the collapse rescue from being carried out.

Again, as with the gas, the utility companies should be called to the scene to shut off the electricity; however, firefighters should be ordered by the chief officer in command to attempt electric supply shut-off prior to the arrival of the utility company.

If a firefighter gets a metal tool entangled in a live electric wire, the continuous electric current shooting through the metal tool and through his body may keep his hands gripping the electrified tool, lock his jaws together, preventing him from calling out for help, and slowly interrupt his regular heart beat until he is electrocuted.

HEAVY CONSTRUCTION EQUIPMENT

Heavy mobile construction equipment, such as cranes, front-end loaders, dump trucks, bulldozers, and tow trucks, are required at every major collapse rescue operation. First, the cars surrounding the collapse area will be towed away to allow heavy equipment to be brought in close to the collapse site. Bulldozers may be used during selected debris removal to move rubble taken from the collapse pile by firefighters. The bulldozer will clear a sidewalk of rubble and pile it at a remote loading point. Here, a payloader will be required to load the nearby dump trucks. Dump trucks must have space to park while awaiting loading. Road access in and out of the collapse area will be required. Finally, a crane and bucket will be moved into the collapse area for general debris removal.

A general rule of safety during a collapse rescue operation states that heavy mechanical equipment should not be used on the same collapse rubble pile where rescue workers are also digging with hand tools for buried victims. Either mechanical equipment, with one or two firefighters as guides, will remove the collapse rubble, or firefighters will remove the collapse rubble by hand. Operating a crane, payloader, or tow truck near firefighters engaged in hand-to-hand digging is extremely dangerous and should not be permitted. Just as when fighting a fire large outside master streams that can collapse a burning building should not be used while firefighters are inside a building using interior handlines, so should operation of heavy mechanical equipment on a collapse rubble pile be avoided while firefighters are working on the pile. Use one type of rubble removal a_____ a time: either heavy mechanical equipment or hand digging, not both at the same time.

When a crane and bucket are used during general debris removal, the bucket picks up the rubble from the collapse pile and dumps it at the central loading point. At this point, firefighters must examine the debris for evidence of victims. After examination, payloaders fill up the dump trucks. The location where the collapse rubble is being dumped must be made known to the officer in command of the rescue operation.

Firefighters should be removed from the area of heavy equipment use. Heavy equipment employing wire cables to pull cars or large pieces of collapse rubble may snap and break. A cable whipping through the air can decapitate a firefighter. Firefighters could be crushed beneath the wheels of a piece of heavy equipment which will not be required to move in the normal traffic patterns. Furthermore, large pieces of wood and steel often drop from the clam bucket of a crane while it is moving material from the collapse rubble pile to the central loading point.

Because of the dangers presented by the use of heavy construction equipment at a collapse site, a chief or company officer should be placed in charge of its operations. This officer should coordinate its use with other phases of the collapse rescue operation and ensure that this equipment is used in a safe manner.

SEARCH BELOW GRADE AREAS

During a building collapse caused by a tornado, earthquake, or aerial bomb attack, people are advised to take refuge in the cellar. The cellar of a structure will often remain unaffected by collapse of the walls and floors above. The masonry foundation walls of a cellar may be thicker than the walls above, but they cannot collapse outward because they are reinforced by the earth surrounding them, and the floor separating the ceilar from the first floor, often reinforced with steel columns and girders, can support more load than the upper floors.

A cellar must be searched for trapped people because this area will create the largest and strongest void in a collapsed building, and there is a good possibility that people may have taken refuge there. Access to the cellar can be accomplished from the outside perimeter of the building even when the entrance hallway has collapsed. Cellars are sometimes accessible from sidewalk trap doors, cellar stairs at the rear yard, or side ground-level window wells.

Accessing the cellar may lead firefighters to an interior cellar stairway that, in turn, could lead upward into the interior voids of the collapse structure. Hours of digging down through a collapsed roof may be avoided by entering a cellar, then climbing up the cellar stairs into the voids of the collapse structure to free trapped victims below a fallen roof or top floor.

However, firefighters must realize that entering a cellar during a major structural collapse is an extremely dangerous operation. The below-grade atmosphere could contain carbon monoxide from a fire above. The oxygen in the cellar could be depleted, replaced by a gas, such as carbon dioxide, that will not support life. A combustible gas such as propane or methane may have filled the cellar. Even though it may be too rich to explode, it could replace all the oxygen, asphyxiating a firefighter who enters the cellar without a selfcontained breathing apparatus already in place. Toxic liquids from broken containers on the floors above could be leaking down into the cellar area.

Water from broken pipes, too, will accumulate in the cellar area. If the electricity supply to the collapsed building has not been shut off, a firefighter standing in water who contacts an electric supply line could be electrocuted. If the structure contains a subcellar (a cellar below the cellar) and it is filled up with water, a firefighter may not be able to see the subcellar stair entrance and could fall in. Submerged in the water beneath the cellar floor, the firefighter will have but a minute or two to relocate the subcellar stairs, or he will drown, trapped beneath the ceiling of the subcellar. When walking in a cellar floor covered with one or two inches of water, the firefighter should probe the floor surface beneath the water before taking any forward step.

Before searching a below-grade area, a firefighter should: ensure that the electric supply to the collapse building has been shut off; use a search rope so rescuers could locate him if he becomes trapped; be equipped with a self contained breathing apparatus, a flashlight, and a portable radio, and be in constant communication with a supervisor.

FALLS, CUTS, ABRASIONS

Most injuries that occur to firefighters during a collapse rescue operation are caused by falling or tripping while climbing the uneven surface of the collapse rubble pile. This danger is not as great as a secondary collapse or explosion and fire; however, if a second collapse, explosion, or flash fire should occur while firefighters are working on top of a collapse rubble pile and are ordered to retreat quickly back down off the pile, many injuries will occur from falls and tripping.

During an emergency evacuation of the collapse rubble pile, firefighters will break bones and suffer puncture wounds and deep lacerations from falling on the uneven surface of the collapse rubble pile. The surface of a collapse rubble pile consists of chunks of masonry, wood timbers sticking up out of the debris, twisted pieces of steel and wire cable, broken sections of plaster walls, wood lath, pointed nails, boxes, and broken pieces of furniture.

Firefighters climbing to the aid of injured people are not able to choose the safest path. The rescuing firefighter must look ahead, guess what piece of debris looks most stable, step on it, and then hope it supports his weight. At nighttime, of course, movement becomes more hazardous. During a nighttime collapse rescue operation, the rubble pile should be lit up with floodlights and spotlights to reduce injuries due to falls and tripping.

Photo by Tim Klett.

To minimize the incidence of falls, firefighters should reduce the amount of walking they do on the uneven collapse rubble pile. Instead of walking up on the pile, picking up a piece of debris, then walking off the pile; firefighters should be lined up in a passalong row, sometimes called a “human chain.” Debris should be passed from firefighter to firefighter while they remain relatively stationary.

Another protection against injury caused by falls or tripping on the collapse rubble pile is firefighter protective clothing. The padding of the insulated firefighting clothing may soften the impact of a fall. A torn or ripped turnout coat or bunker pants may occur during a fall, but this probably would have been a cut or puncture wound if no protective clothing were worn.

During the most dangerous stages of a collapse rescue operation in particular-site survey, surface search of the collapse rubble pile, and void searchprotective fire clothing must be worn. There is a great danger of secondary collapse, explosion, or fire. During selected debris removal, the officer in command should consider allowing firefighters to remove fire clothing, with the exception of helmets and boots, during a long digging operation.

UNCOORDINATED COLLAPSE RESCUE OPERATION

When rescue workers are from several different organizations—fire department, police department, construction companies, emergency medical services—there is danger of uncoordinated, uncontrolled rubble removal. Uncoordinated rescue work can be deadly. Some rescue workers might pull collapse rubble down on top of other rescuers. Some rescue workers might cut structural members supporting other rescue workers. Some rescue workers using mechanical equipment might injure other rescue workers digging by hand.

When several different groups are engaged in collapse rescue work, there should be one person in charge to coordinate the collapse rescue personnel operating in the collapse rescue site. This coordinator must be designated and recognized by people in charge of all the agencies, and all personnel digging on the collapse pile must be informed of this designation. His primary responsibilities are the rescue of all victims buried in the collapse and the safety to collapse rescue workers. This coordinator should direct the collapse rescue operation according to the standard collapse rescue plan.

A building collapse rescue operation is one of the most dangerous jobs to which a firefighter can respond. The dangers present at a collapse have been described above. The following are some safe operating procedures:

1. Stretch a hoseline to protect rescuers from any sudden explosion or flash fire.
2. Follow the standard collapse rescue plan:
1. Site survey
2. Collapse rubble pile surface search
3. Void search
4. Selected debris removal; tunnel/ trench to specific locations General debris removal
3. Shut off all utilities—gas, electric, water—as soon as possible.
4. After site survey, surface search, and void search are completed, temporarily withdraw all rescue workers from the pile. Increased safety precautions should be taken. The most productive lifesaving stage of the rescue plan is over. Although we continue to dig for buried victims, the cost (danger to firefighters)/benefit (chance of rescuing victims) relationships has changed against us. We continue selected debris removal after serious secondary collapse, fire, and explosion dangers have been eliminated and we use fewer firefighters.
5. During night operations or at a major structural collapse that will be of long duration, obtain portable lighting equipment.
6. When there is a danger of secondary collapse, use a transit (surveyor’s tool) to measure any movement of the structure. If a wall moves more than a quarter of an inch during a collapse rescue operation, rescue workers should be removed from selected debris operation and the wall either shored or removed by a crane.
7. Set up a command system to coordinate the collapse rescue operation. Use a command system modeled after the incident command system taught at the fire academy. (See example below.)
8. Designate a collapse rescue coordinator. Notify all agencies that the coordinator is temporarily in charge of rescue operations. This rescue coordinator should be knowledgeable in collapse rescue operations.
9. Assign an officer to victim tracking. Record data such as name, location found, diagnosis, physician or medic name, facility to which transported and by whom.
10. Do not use mechanical equipment to remove collapse rubble at the same time that hand digging is being done.
11. When there is danger of secondary collapse, do not pull down collapse structures in danger of collapse with wire cables. Shore them up or, before selected debris removal begins, remove them with a crane after all rescue workers have been removed from the collapse rubble pile.
12. Secure the collapse site before leaving the scene to prevent injury to citizens.
13. Photograph the collapse operations to obtain visual training aids.
14. Never give up hope of finding victims. People have a good chance of survival if rescued within 24 hours. People have been buried in collapse rubble for up to 11 days and lived.
15. Do not stop selected debris removal until all victims reported missing have been accounted for. During general debris removal, examine all rubble taken from the collapse for remains of persons buried in the collapse but not reported missing.

A Command System For Use At A Collapse Rescue Opera