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Training Day
Training for trench rescue

In this issue I will provide an overview of a recent rescue operation at which I was the first due Special Operations Officer.  After the overview I will offer some thoughts on how to apply lessons from this operation to your training program.

On the afternoon of June 18, 2013 FDNY units were called to the scene of a reported trench collapse in the Kew Gardens section of Queens. A laborer, who had been working in the excavation, had been caught in a collapse. According to reports fellow workers had tried to extricate him for an hour and a half before calling 911. 

While responding to the incident I received reports of a confirmed trench collapse with an entrapped victim.  Upon arrival I reported in to the Chief in charge along with my two entry FFs (firefighters). At this point the first due units had been able to make contact with the victim and had begun to secure the scene.  Workers who had been in the hole attempting to dig out their coworker had been removed. In addition members of the first due units who had initially made victim contact had also been removed in order to begin safing the trench. My initial assessment indicated that the victim was buried in an excavation not a trench (According to OSHA a trench is defined as a narrow underground excavation that is deeper than it is wide, and no wider than 15 feet) to approximately waist high. Distinguishing between a trench and an excavation is not mere semantics; it implies utilizing a different set of tactics to mitigate the hazards of secondary collapse as well as to facilitate victim extrication.  The victim had been buried by a cave in at the base of the excavation; and upon initial observation appeared slightly lethargic. In addition to burying the victim this had undermined the overhanging wall.  An estimated weight for this overhang would be approximately 1 ton for a column one-foot square. While this incident was an excavation and not a trench it had maintained many of the negative attributes of a trench rescue without the associated positive attributes that normally aid in hazard mitigation. This was due to the depth of the excavation as well as the victim’s location. 

There were however two fortunate circumstances that were to aid in mitigating the secondary collapse hazard. Three I-Beams had been installed as underpinning along the vertical wall that was considered the primary secondary collapse danger. This underpinning would be utilized to support the placement of whalers (walers, wales) to assist in stabilizing the wall as well as to hold trench panels in place. Along with the underpinning another fortunate state of affairs was that the bucket of the excavator was buried in the collapse adjacent to the victim; enabling the arm of the excavator to be utilized as a very stable, albeit unconventional anchor point for shoring up the trench.   

While the initial scene assessment was being conducted my other FF’s were coordinating with the first due units to offload and stage the bulk of the trench rescue equipment. After the equipment was removed the apparatus’s were repositioned to allow for the placement of crucial equipment. This included a tower ladder, vacuum trucks, and possibly a dewatering unit that would hopefully not be needed.   

At this point one FF wearing a safety line entered the excavation from the rear slope to begin victim extrication. Simultaneously other members were assisting with the lowering and positioning of horizontal whalers to be installed behind the existing underpinning to help mitigate the effects of a secondary collapse. The entry FF initially operated in a relatively safe zone located between one of the underpinnings and the arm of the excavator.  These initial operations included: establishing the first point of attachment with the victim utilizing nylon webbing; safing the area around the victim utilizing plywood; and beginning soil removal. These initial steps were crucial to scene stabilization.  By establishing a point of contact with the victim and placing it under tension, several things were accomplished: it provided a means to relocate the victim should a secondary collapse occur; it provided for the means of eventual victim removal; and it prevented the victim from sinking further into entrapment either due to the soil type (victims will sink into mud) or to the undermining of the victim that occurs through digging and the use of the vacuum truck. Due to the very limited safe area of operations available it was determined that the other members would not enter the excavation at this time but would instead begin safing the excavation. These safing operations included the placement of ground pads around the lip of the trench, placing trench panels, and setting up and operating pneumatic struts.

In a traditional trench, the pneumatic strut placement would have spanned the trench horizontally between sets of trench panels to mitigate the secondary collapse hazard. Generally this is not possible in an excavation.  The procedure often used in excavations to protect the victim is to use an overpack drum, with the bottom cut out, placed over the victim. At this point in the operation one member was utilizing a torch to cut the bottom out of a drum for this purpose. This solution was to prove unviable for several reasons: because the victim was directly at the base of the partially collapsed wall of the excavation, the barrel would have offered minimal protection in a secondary collapse; in order to place the drum, the wall would have to be further undermined possibly causing a secondary collapse; and in this configuration the drum would not have allowed for the removal of dirt from around the victim. Other shoring options were also not realistic as the shoring necessary would have required excessive lumber and time which, due to the victim’s condition, was deemed impracticable. 

The tower ladder used as a high point was in position at this time and members had rigged the main and safety lines to it.  These were attached to the victim and put under light tension.   Later they would be used for victim removal. 

Continuing safing operations, members operated installing trench panels. These panels were anchored by various means.  Strut placement was predominantly on the arm of the excavator.  This required the utilization of specialized bases for the struts as opposed to those usually used for trench rescue. These bases allowed the struts to lock into the angles of the excavator’s arm and around the pistons. Employing the typical bases would not have provided a reliable support for the struts.  By this point in time the excavator had been tied back utilizing two cable hoists to further stabilize the situation. In addition to struts, panels were held in place by whalers and wedges positioned behind the existing underpinning. 

Upon the arrival of the vacuum trucks (supplied by Con Ed, the local power company) members worked with the drivers to setup for operations. At this time confirmation was received from EMS that crush injury protocols had been initiated. 

As the digging progressed utilizing hands, buckets, and the vacuum trucks for dirt removal, as well as an airknife to break up the dirt, members rotated through the digging positions. After the victim was freed and hoisted clear of the hole he was placed on a backboard, collared and lashed into a Stokes basket. The final removal of the packaged victim was up the rear wall of the excavation through a combination of hauling and carrying as is common in low angle rescue.

 

Lessons Learned

In his book The Rescue Company, Chief Ray Downey, when addressing the calling of additional equipment/units utilizes the phrase “Proact rather than react.” This principal was utilized throughout the operation, beginning with the early call for vacuum trucks. This should be incorporated into your training by requiring a realistic amount of time between the request for resources and them being provided. 

Analyzing the risk verses benefit – In the case of this operation the victim was considered viable, but due to his lethargic appearance, and the length of time some of the other options to safe the excavation would have taken, it was unclear that he would remain viable for the time required.  I can contrast this to a trench job that I operated at in Brooklyn. In that case after the victim was uncovered Rescue Medics were sent in and after examining the victim pronounced him DOA.  At this point we removed everyone from the trench and reset all of our shoring; reasoning that there was no reason to continue the extrication of an unviable victim in anything less than a completely safe manner. This decision making process can be integrated into your training by providing varying information regarding the victims condition and other variables.  In these trench operations the patient’s condition dictated mode/speed of removal. To incorporate this with something like meter readings the trainees should evaluate what they really have and report it (i.e. 21 percent oxygen in air). Then a facilitator can give them readings to be used for the scenario (i.e. 17 percent oxygen in air).

Don’t be too rigid in your thinking; maintain the ability to think outside the box.  Field Marshall Helmuth von Moltke is credited with the quote “no plan survives contact with the enemy,” (also translated as no plan survives the first shot, etc.) You have your initial plan and after that you must be flexible.  The shoring utilized at this operation did not fit into any of our neat categorizations but the basic principles remained intact. That being said you should have a plan/SOP.  In fact you should have a plan A, B, C … etc.  When our normal strut placement SOP’s proved unsuitable the overpack drum was considered. When this proved inappropriate the underpinning and the arm of the excavator were utilized.

Training must be conducted with the resources and personnel that you will actually work with. This could be resources that you have on hand, such as the unit with the tower ladder in the scenario, or outside resources such as the Rescue Medics and the vacuum trucks. As an example one of these vacuum trucks along with an operator always attends the final day of our trench rescue course. This also reveals unforeseen equipment compatibility issues. 

Train to the appropriate level of training.  In the above scenario if you were required to operate as the first due unit while awaiting for more specialized mutual aid, a basic awareness or operations level of training would be adequate. If however you were expecting to operate as the Special Operations units did, than a more advanced, technician level of training would be required. 

Evaluate your training so that you train for what is appropriate for your perceived hazards.  In speaking with experienced members of my command we estimated that 75 percent - 80 percent of the trench rescues that we respond to are really excavations. Yet our curriculum is almost 100 percent trench rescue. This has caused us to reevaluate our curriculum in order to have it reflect our reality.  These perceived hazards could change as your experience grows or as new hazards reveal themselves.        

James Kiesling is a Captain with the Fire Department, City of New York’s Special Operations Command.  He holds a bachelor of arts in fire and emergency services from John Jay College of Criminal Justice and an associates degree in occupational studies in fire protection technology from Corning Community College.

        

 

 
 

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