Kiesling supervises void entry training at the FDNY academy in November 2013 using a collapse simulator - Photos courtesy of James Kiesling

Kiesling supervises void entry training at the FDNY academy in November 2013 using a collapse simulator

Photos courtesy of James Kiesling

A victim of the 2010 Haiti earthquake, face covered to prevent injury, trapped in a void beneath a pancake collapse. -

A victim of the 2010 Haiti earthquake, face covered to prevent injury, trapped in a void beneath a pancake collapse.

This is the third and final installment in a series on training for collapse operations. In the previous columns I wrote discussing: how to establish what your collapse rescue training needs are, an overview of the five stages of collapse rescue operations, and stages I and II in greater detail.  In this article I will elaborate on stages III to V of collapse operations and the pre-planning and training that would be required to conduct such operations. 

Stage III Void Entry


          As the surface rescue stage of the collapse rescue plan is being completed the void entry phase can begin.  Before initiating void entries, among other factors, you should take notice of the type of collapse.  As has been previously mentioned FEMA engineers use the collapse patterns as one of the criteria to determine the viability of survivors and to prioritize searches.   Examining these patterns will provide you with potential routes of egress into the collapsed structure as well as indicating the areas that have the greatest potential for survivability. 

          The most common method for classifying collapse patterns breaks them down into five types: supported lean-to, unsupported lean-to, A frame or tent, V shaped and pancake.  Both the NFPA and the Fire Chiefs Handbook utilize this system with minor deviations.[1] Other sources such as FDNY’s collapse procedures[2] and Deputy Chief Vincent Dunn’s Collapse of Burning Buildings describe other collapse patterns but the five previously mentioned are generally taught in regards to void entry. 


Lean-to collapse -

Lean-to collapse

Supported lean-to collapse – this pattern occurs when one end of a floor or roof drops down while the other remains up forming a lean-to.


A-frame collapse -

A-frame collapse

A frame or tent collapse - this pattern is basically two supported lean-to collapses with the floor or roof dropping down on the outsides while remain supported in the center.


V-shape collapse -

V-shape collapse

V shaped collapse – this pattern like the A frame collapse also involves two supported lean-to collapses however in this case the failing floor or roof fails in the center and remains supported on the outside of the pattern. 


Unsupported lean-to collapse -

Unsupported lean-to collapse

Unsupported lean-to collapse – this pattern resembles the supported lean-to collapse however unlike the previously mentioned collapses where both ends of the structure remain supported in this pattern the failing floor or roof ends up suspended in the air. Since one end remains unsupported this pattern is particularly prone to secondary collapse. 


Pancake collapse -

Pancake collapse

Pancake collapse – in this pattern the roof and or floors fall straight down and resemble a stack of pancakes.


In general in these collapses viable victims will be found in the void created under the lean-to effect, and at the bottom of the slope created on the top of the lean-to effect.  In the case of the pancake collapse viable victims will be found in voids created where the collapsing structure came to rest on a substantial object such as a desk or a piece of machinery. [3]


After identifying the voids and the most likely locations of viable victims you can begin your void search.  This can be done visually be looking into the void or by entering a void and visually searching the area.  A hailing search is another simple and effective method of search.  In this type of search the rescuer simply calls out and asks if there is anyone in there.  This callout is followed by a brief period of silence to allow anyone that is trapped to answer.  These are both manpower based methods of search.  Another category of search is canine.  Canines are a great asset that in many circumstances can search a large area in a short period of time.  There are several items to keep in mind when deciding on whether or not to utilize canines as part of your planned response.  One is, are these assets trained and certified.  Sometimes in a disaster you can be subjected to well-meaning but not necessary helpful people.  Another item is availability.  If a collapse is a localized incident a mutual aid agreement, to have canine assets respond, will work; however in the case of a large scale incident such as an earthquake these assets will most likely be unavailable.  The final category of search is technical search.  In this method rescuers search with items such as: fiber optic cameras and seismic/acoustic listening devices.  Devices in this category while useful are expensive and require an advanced level of training.  Also the canine and technical search assets are not “cure alls” they are just tools. 

In some cases it may be necessary to install shoring before entering a void.  Shoring consists of temporary structures for the purpose of supporting the collapse.  This is put in place to provide a protected area for search and rescue operations.  Shoring can be commercially made or built with wood.  While a very basic level of shoring competency is easily obtainable anything beyond that requires specialized training.  For specifics on shoring construction the DHS has a manual on the latest shoring techniques.[4]   Many of these techniques were developed in London during the bombings of WWII and have been highly refined by FEMA. 

          When conducting a search it is important to record all the areas searched.  The purpose of this is to ensure that the entire collapse zone gets searched and to avoid a duplication of efforts.  The duplication of efforts is bad for two reasons.  One is that it wastes time and manpower by having resources searching an area that is already searched when they could be searching an area that needs to be searched.  Another is that it needlessly puts rescuers in harms way, searching an area that has already been searched.  Is a simple collapse scenario, such as a single small structure, the FDNY calls in search results to the Chief (incident commander) who records these results.  In any incident of greater magnitude than the above, the actual structure should be marked with the results of the search utilizing the standardized USAR marking system.  Areas that have been searched are painted with an X.  The first slash of the X is painted at the beginning of the search and the second when the search is completed.  Information written with the X includes: who conducted the search, time and date of the search, results of the search, and any hazards found.  For a detailed explanation of this marking system consult the USAR FOG manual.[5]


Stage IV Selected Debris Removal


As a general rule the selected debris removal stage begins after the void entry stage is completed although this may not be the case in situations such as when there is a confirmed victim or a large scale operation.  Selected debris removal is performed for the purpose of reaching a particular location. This location could be at the victim or an area of the structure where viable victims are likely to be.  A typical void entry could begin with entering an open void and progress to removing loose debris to cutting and breeching operations.  Any cutting, breeching or breaking operations must be untaken with extreme care.  Thought must be given to not just the structures reaction to the item being cut but also to the vibrations and other byproducts of tool operation.  In a simple wood frame structure these operations can be performed with little more than a reciprocating saw.  On the other hand, in a collapsed reinforced concrete structure numerous specialized tools can be required.  All requiring specialized training. 


Stage V General Debris Removal


The general debris removal phase of operations generally begins when the other stages are completed and there are people still missing but presumed dead.  In this stage the scene is systematically delayered, often utilizing heavy equipment, with the debris than being spread out in a designated area and searched before being reloaded and removed.  This should be recorded in a demolition debris removal log and the operations continued until all persons are accounted for. 




To illustrate the potential importance of a facility having some level of collapse training; since the last installment of this series I have responded to several collapses including a truck into a facility dealing with compressed gasses, a gas explosion in a private dwelling, and a concrete pump truck that crashed into a structure.  This last incident killed the driver, injured several others, resulted in the structure being a total loss, and requiring three wreckers and eventually a crane to extricate the vehicle from the structure.  Collapse scenarios are not uncommon.  That being said it would be the rare facility that would require the capability to carry out operations at the highest levels.  To operate at these levels requires a substantial commitment to equipment and training.  Some examples of facilities that could require a higher level of training would be: isolated or overseas facilities in areas with limited local response capabilities; or facilities in danger areas such as earthquake zones where the resources that you planned on would be stretched thin when you were most likely to need them. 

After an initial level of training is obtained collapse rescue training can be broken down into its component skills when conducting refresher training.  This training could include such items as, shoring, void entry with selected debris removal, breeching and breaking, search marking systems, and reviewing building types and collapse patterns. 


Those that are interested in the training requirements for the various levels of response are encouraged to review the collapse rescue portions of NFPA 1670 Standards on Operations and Training for Technical Search and Rescue Incidents.



James Kiesling is a captain with the FDNY’s Special Operations Command.  He holds a bachelor of arts in fire and emergency services from John Jay College of Criminal Justice and an associated degree in occupational studies in fire protection technology from Corning Community College.


[1] National Fire Protection Association (NFPA).  NFPA 1670 Standards on Operations and Training for Technical Search and Rescue Incidents 2009 Edition, Quincy Massachusetts.

* This is the primary method of classifying collapse patterns found in Building Collapse Patterns, 1st section of Annex J and is followed by other methods of collapse classification.

[2] Fire Department City of New York, Firefighting Procedures, Collapse Operations, 2007, Brooklyn, New York.

[3] Much of the collapse of the WTC did not conform to any of these patterns; often resembling a large pile of pick up sticks

[4]Department of Homeland Security (DHS), Department of Homeland Security Field Guide for Building Stabilization and Shoring Techniques, 2011 available at

[5] Urban Search and Rescue, Field Operations Guide, 2006, available at