SUBJECT: Cable Median Barriers — Part 2 TOPIC: Cable Median Barrier Incident Procedures OBJECTIVE: Responders shall develop procedures for operations at center median incidents when a vehicle is contacting or entangled in tensioned cables TASK: The rescue...
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SUBJECT: Cable Median Barriers — Part 2
TOPIC: Cable Median Barrier Incident Procedures
OBJECTIVE: Responders shall develop procedures for operations at center median incidents when a vehicle is contacting or entangled in tensioned cables
TASK: The rescue team shall develop a department guideline for incidents with vehicles in contact with the cable median barrier system based on the model eight-step procedure presented
In part two of our series on high-tension cable median barriers, we study a recommended eight-step procedure for dealing with vehicle collisions when tensioned cable barrier systems are involved. Using a real-world incident as our case study, we will work through this model step-by-step decision-making process that rescue officers can use to safely and effectively manage a cable barrier incident.
Decision Point 1, our first step in dealing with cable barriers, comes as we arrive at the incident. During our initial scene size-up, we must determine whether a cable median barrier system is present at the collision scene we are arriving at. If cables are present, then Decision Point 2, our next step, is to determine whether the damaged vehicles are contacting any of the three or four cables in any way. If all vehicles are clear of the cables, then standard operating procedures (SOPs) can be followed for dealing with the incident as if the cables weren't even there.
If the vehicles are contacting the cable system, then during Decision Point 3 we determine to what degree the cables are obstructing the crash-damaged vehicles. Rescue personnel typically obtain access to occupants of vehicles by opening a door. The degree of obstruction presented by the cables must therefore focus on whether any doors are blocked and whether side windows, the windshield, or the roof area of the vehicle are directly contacted by the high-tension cables. If the occupants got out of their vehicle before you arrived, then cable contact is less important. If, however, one entire side of the vehicle is blocked and you determined that opening those doors will be required to get the patients out, then responders must continue dealing with the cables.
Decision Point 4 involves determining whether the obstructing cables can be moved manually. It may be possible for several crew members to move the cables enough to allow a door to be opened or the roof to be taken off. If there is no slack in the cables, making them too difficult to move manually, then responders can continue on to the next tactic.
Decision Point 5 involves relaxing the tension on the obstructing cable or cables in a controlled manner. To do this, personnel with tools such as large pipe wrenches, locate the cable turnbuckles that are on each side of the incident scene. Remember, each cable run is approximately 1,000 feet in length. At this interval, a turnbuckle assembly will be present that allows the next run of cable to be joined and tension to be placed on the cable itself. Once the turnbuckles are located on each side of the incident scene, crews can release tension by backing off the turnbuckles. If this is successful, enough slack may be introduced that the obstructing cables can now be moved. If relaxing the turnbuckles still does not allow the obstructing cable to be moved, then we continue on to our next tactic.
Decision Point 6 involves efforts to manually move or remove the supporting posts. By moving the posts or removing them from their sockets, additional slack may be introduced into the cable that is obstructing your patient's vehicle. Be careful when moving a post out of its ground mount. If it is stressed or the nearby cable is stretched or twisted, anticipate any unwanted movement of the post as it is moved.
If all these efforts have been unsuccessful, then our "last resort" tactic will be to cut a turnbuckle or the cable itself. This is an involved process that should be attempted only after all the previous efforts have been tried and found unsuccessful. When cutting a tensioned cable, there is an inherent higher degree of risk for personnel at the incident scene; therefore, it must be done with due regard for safety.