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Physical search is the most dangerous for rescuers, because it involves deploying personnel over and around a collapse and actually committing rescuers into unstable void spaces to physically search for victims. One method employed by firefighters conducting physical searches in void spaces is termed "Round-the-Clock." After complete silence is obtained (all radios turned off, etc.), members try to establish contact with any victims and determine a "fix" as to their location. Once a "fix" has been made, an additional "fix" is attempted from another angle to minimize error. Once communication has been established with a victim, one member is assigned to maintain this vital link.
Photo by Dan Quimby
Specialized rescue equipment, such as this portable hydraulic generator with a rotary hammer drill.
Electronic search is usually employed in the form of acoustical listening devices. These instruments are designed to pick up the slightest sound(s) of a buried victim. One style of this piece of equipment has two leads which can be stretched in different directions and, along with a metering device, can pinpoint the location of a victim buried under the rubble of a collapsed building. This is a slower type of search, but it is not nearly as risky to rescuers.
Canine search involves dogs and their handlers specifically trained in building collapse operations. Canine search teams should be available from the outside resource list. This type of search covers the largest area in the quickest amount of time, and was used with great success in the Oklahoma City Federal Building bombing and during numerous operations following earthquakes in California.
Fiber-optic search is the most sophisticated and the most accurate type of search method. It is used in conjunction with concrete or masonry drills that bore narrow inspection holes. The flexible scope of the camera is then inserted into the holes, and a television-like picture is then transmitted back to the operator. This verification leaves no guesswork as far as the location of the victim and the degree of entrapment.
It is standard practice to blend all of the four search capabilities into one logical plan. The area in question should be sectored, and general features of the structure should be sketched to use as a reference. Buried victim location should be confirmed by two separate search methods whenever possible.
A systematic search of all collapse voids should occur. Obviously, natural voids (voids already created by the collapse) should be searched prior to trenching and tunneling. Natural voids will be the fastest and easiest to explore, and most surviving victims will be found there. During the void search phase (after natural voids have been identified and searched), trenching and tunneling may be required to reach buried victims. In this operation, void spaces are created by rescuers. This operation is extremely dangerous because of the potential for rescuers to cause a secondary collapse.
Photo by Pete Lund
A hydraulic-powered chain saw with a diamond-tipped cutting chain, allows rescuers to penetrate concrete effectively during collapse rescue operations.
Once the location of buried victims is confirmed, a transition is made from search to rescue operations. Most collapse rescue operations benefit from a "two-sided" approach. This two-sided approach was successfully used at a recent building collapse operation in Philadelphia where seven firefighters were buried. One approach was from the top down and one was from the Exposure D (or Exposure 4) side. This resulted in firefighters being extricated through the top and the side; both approaches taken by rescuers led to the same voids involved. If the attempt in the first area takes longer than expected (or no longer becomes viable due to unforeseen obstacles encountered), the second access route is already identified, and work in that area is already underway, saving valuable time.
While some shoring activity will most likely have occurred as the search is being conducted, shoring operations will increase in complexity as breaching and tunneling is done to reach the victims and extricate them. Collapse rescue shoring is defined as the temporary support of only that part of a damaged or partly collapsed structure that is required for conducting operations at reduced risk.
Weights of common building materials have a definite impact on the type of shoring system constructed. The difference between wood debris (35 pounds per cubic foot) and steel debris (almost 500 pounds per cubic foot) is substantial, and shoring systems have to be constructed in order to support the total load encountered. A quick rule of thumb used to calculate the weight of concrete or masonry rubble is 10 pounds per square foot (per inch of thickness).