A few months ago we had a minivan that impacted another vehicle in the middle of an intersection. It then proceeded to travel over a ravine and came to rest against a concrete barrier, approximately 20 feet down the cliff edge.
To make matters worse, the minivan was handicap equipped, the driver was wheelchair bound and the vehicle was completely shrouded by heavy foliage. Our auto-accident run immediately moved into the realm of a multi-discipline general rescue.
Events like this can tax the most seasoned crews. When a rescue involves multiple disciplines we have to be well versed from a knowledge, skills and abilities perspective and be well equipped to tackle these challenging events.
In this event, we stabilized the vehicle by attaching grade 80 chain assemblies to the vehicle's rear frame and anchoring them to a fire apparatus. The vehicle was positioned nose down, so we removed the rear deck lid and seats, constructed a lower/haul system and belay using a RPH and an MPD, and then inserted rescuers into the vehicle.
The locking mechanism for the wheelchair was disengaged and the driver transferred to a long board and packaged for vertical retrieval. The hauling system with a 3:1 mechanical advantage was then used to retrieve the victim through the vehicle.
The run took less than 40 minutes and used six companies: one battalion chief, two medics, one heavy rescue, one squad and one quint. This run was an overall success because the appropriate resources were available and the personnel on scene were adequately trained.
One of the keys to this success was rapid delegation of responsibilities. The officers on scene quickly formulated an action plan and made assignments. One crew was assigned stabilization while the other crew prepared for extrication and rescue. Both groups were given clear benchmarks and objectives and worked independently but maintained effective communications.
Using the vehicle itself as a channel to tunnel into and extricate the victim allowed rescuers to avoid the foliage and obstacles that the natural terrain presented. It also afforded a more stable platform for rescuers.
The hauling system was developed while rescue crews were packaging the victim and all of the pieces came together. An interior safety officer insured that rescue crews conducted safe and effective operations in the vehicle and a safety officer at street level ensured that retrieval was coordinated and engineered appropriately.
Another example involved an individual fleeing from the police who lost control of his vehicle, careened off of the road and struck a residential structure. The vehicle was on all four wheels but was teetering on the lower portion of the remains of an outside wall.
A corner of the structure was completely compromised and the roofline had dropped approximately two feet. The structure was light-frame construction and presented immediate concerns for making a safe approach to the vehicle to assess and potentially extricate the victim.
Additionally, the victim was a safety concern. At this point the run became much less dramatic because the driver had self extricated prior to emergency crew arrival and fled on foot.
Arriving companies were no longer in rescue mode and went into overhaul mode to make the structure safe and gain access to the vehicle for removal applications. The event was an exceptional training tool to rehearse and apply the tactics and techniques that would have been used if the driver had required extrication.
The officer's first objective was to make the scene safe. This required two initial considerations: the structure, and the vehicle and driver.
The structure was deemed to present a potential immediate threat because of the significant damage to the primary supporting walls. The roof system was light-weight truss and several of the trusses were completely unsupported.
This assessment presented a choice to avoid the hazard, monitor the hazard or shore the hazard. The hazard could not be avoided because the victim and vehicle were directly in the hazard zone. The hazard also could not simply be monitored because crews would have to gain access to the hazard zone to extricate the victim.
This left us with the shoring option. Shoring can be very time consuming or relatively quick depending on the type of shore required and the equipment available to construct that shore.
The outcome ended up being a moot point because of the type of structure. Light-weight wood frame structures present limited loads and propensities for secondary collapse in this scenario. Typically speaking, temporary shores and Class II vertical shores are adequate to safely and effectively shore these types of structures.
This conclusion is derived from some basic structural-load estimations and the behavior characteristics of construction types in a collapse scenario:
- Wood floors weigh 10 psf to 25 psf
- Frame walls with gypsum board on each side weigh 7 psf to 8 psf
- Wood joists at 16 inches off center weigh 3 psf
These shores are much faster to construct than Class III shores and allow crews to shore and gain access in a rapid fashion provided they are well equipped.
The right equipment
Rescue crews have a wide array of equipment options for this type of rapid shoring. Whatever option is chosen, the shore should follow the double-funnel principle that uses a header to collect the load, a vertical member to transfer the load, and a sole to disperse the load.
Additionally, the shore should follow guidelines set forth by the Army Corps of Engineers and FEMA or a certified engineer who has tested and certified the shore.
One of the first components crews should acquire are 36-inch headers and soles. Precut 4x4 dimensional timber to this length and store these on the apparatus. Each pair will give you one temporary shore.
The next part of the shoring equation is the vertical member. Here are four options.
Ellis screw jacks
These are 4x4 or 6x6 cups that receive a dimensional vertical timber that is cut to an appropriate length. These vertical timbers will typically have to be cut on scene because the screw jack has limited adjustability.
Additionally, the vertical has to be married up with the header to form the top half of a T-shore by using gusset plates and approved nail patterns.
These clamps are fixed to two T-shores without sole plates. Construct two top halves of T-shores with gusset plates and headers, turn one upside down and join the two with two Ellis clamps.
The clamps allow the two members to slide up and down providing a large degree of adjustability. Use a special Ellis wrench to the underside of the top T, and the shore is pressurized.
Then fix the clamps in position with nails. This is a very fast shore to deploy and is inexpensive, but takes up a lot of storage space and material.
Single T-shores and double T-shores can be fabricated using all timber components and pressurized by using wooden wedge packs. These shores must be cut and constructed on scene.
Several manufacturers produce lightweight struts that are highly adjustable, simplistic, and the quickest of all of the options for rapid temporary shores or spot shores. These struts are not pneumatically pressurized in structural-collapse applications but rather are mechanically pressurized.
Struts are assembled based on desired lengths using extensions as needed, base plates are attached to the struts, and then the strut assembly is nailed to the header and sole. However, these are on the high end of the cost scale.
In this event, our crews set the struts in place as vertical spot shores and two post vertical shores to support the compromised roof assembly. Once the structural hazard was addressed, crews accessed the vehicle and facilitated its removal.
For this particular event, crews used law enforcement throughout the operation to insure ensure that the victim was not armed and would not present any additional hazard to emergency personnel.
Both of these events required advanced equipment, training and certification in multiple rescue disciplines. These are some of the most challenging rescue sequences.
Crews should table talk these potential events and analyze where their organizational shortcomings lie. Solutions should be developed as theories and then put to the test in practical applications. Re-evaluate, and then make final adjustments.