Elevated water storage tank rescues


CarolinaFireJournal - By Bob Twomey
By Bob Twomey
08/04/2013 -

In the rescue service, rescuers can expect to receive the call that a person on an above ground water tank requires rescue. Generally, you would expect this to be maintenance or service personnel who have had something go wrong and now require assistance.

However, it could be a child who, as we all did growing up, was just exploring and now finds himself in a predicament requiring assistance. It happens and we need to be prepared to handle it, just like all of the other rescues that will confront us.

About Water Tanks

Water tanks come in all shapes, sizes and types and configurations.

image

Development water supply tank.


Rescuers receiving the victim and rescuer as they approach ground level.

Often, the placement of a water tank and its shape or design, are based upon the expected use of the water and how quickly a certain stored volume of water is needed. Certainly you expect to find water tanks around industrial facilities. Likewise, many residential developments have water supply tanks atop a hill or mountain to supply the needs of the residents. Water tanks are everywhere and used for nearly any imaginable use.

Industrial Water Tank

Recently, my department ran a series of classes to instruct rescuers in various methods of tank rescue. But one of the main focus goals was to get the rescuers to study the tank’s location, access and configuration, so that they could determine the most efficient rescue methods available to them. The idea was to again dispel the “tunnel vision syndrome,” see the tank and it’s available appurtenances that could be useful in the rescue, and to determine any hazards around the tanks that could impede rescue.

Municipal water tank.

As is typical in my training scenarios, I chose to emphasize the “rescue tools in the toolbox” principle:

  • determine tank site access
  • study the situation
  • look at surrounding hazards
  • perform rescuer and patient risk analysis/size-up
  • establish an efficient ICS system — do the rescue

“Tunnel vision syndrome” is a situation affecting fire and rescue personnel. It often occurs when rescuers arriving on scene fail to perform proper scene size-up, base rescue plans on assumed conditions, and who fail to understand that the simplest (but safe) method of rescue is not always the one involving complex rescue rigging. While some rescues will require multi-stage complex rigging, many will not. So, my point here is keep it safe and simple.

Obviously, high-level rescue requires substantial knowledge, skill and ability — KSA.

During training, this unconscious maintenance worker is hanging in his safety harness six feet below the top of the tank.

KSA comes from recurrent, diligent and dedicated training in real life scenarios. This takes time, and along the way, experience plays a major role in all of this. Rescue abilities, in any field, come from training and hard earned experience. Seasoned rescuers know that keeping a rescue as simple as possible reduces the risk of a failed rescue. Likewise, technical rescue tools of many types and varieties and rigging knowledge and how to use these tools accordingly and safely round out the necessary requirements to perform rescue safely.

The tank utilized in our training is a residential and small business water supply tank, approximately 30 feet high, holding nearly 250,000 gallons. It is on a hill accessed by a very steep, narrow service road, which eliminated the possibility of victim access by a ladder truck. Therefore, rescue rigging and ladder skills again proved to be the only way to accomplish a rescue, at least on this tank.

Victim wedged in the safety cage surrounding the tank ladder.

Scenario one was that of a maintenance technician who was servicing valves atop the tank. He had a safety harness on and it was attached to a hard point on the top of the tank. However, his measurement on his safety line was miscalculated. During his work, he slipped on the smooth metal top of the tank, striking his head on the steel surface, rendering him unconscious. As he rolled off of the top of the tank, his safety line did arrest his fall to the ground; however, in tying the line off, he misjudged the distance from the center of the tank (his anchor point) to the outer edge. Instead of his safety line catching his weight before the edge of the tank, he rolled off the edge and was hanging approximately six feet below the top edge of the water tank, suspended by his safety harness.

Given the tight quarters around this tank inside the security fence and the steep terrain outside of the fence, rescuers were told to perform a “leaning ladder” rescue.

Basically, the leaning ladder rescue involves leaning the tip of the ladder against the structure and above the victim, and securing the ladder such that it does not move during the rescue.

In this scenario, the base of the ladder is secured with round lashing around the beams and pickets driven along side the base of the ladder, and the ladder is tied off onto hard points on the tank itself. A lowering line is attached to the base of the ladder in a change-of-direction pulley, up to another change-of-direction pulley secured at the top of the ladder around the beams and over the rung of the ladder, onto which the victim’s weight will be transferred.

Victim is supported in four places during the ladder-assisted lower to the ground.

Once the rescuer is at and slightly above the victim, this lowering line is then attached to the victim. The lowering line is then utilized briefly as a “haul line” to raise the victim up a few inches so that the victim’s safety line may be disconnected from his harness. Rescuers on the ground, under direction of the rescuer on the ladder, then begin a smooth lower of the victim to the ground. The victim descends between the underside of the ladder and the tank wall.

This is a very simple way to safely lower the stranded victim from the side of the tank to the ground. Basic ladder and rigging skills were used along with rescuers on the lowering line providing the initial raise to free the victim from his safety line, then lower him to the ground. This technique would also be very effective if frost or ice was on the tank surface, or the tank was otherwise slippery on top. There are limitations. The tank has to be accessible by a 24 foot or 36 foot rescue ladder. Taller tanks would require other methods to effect a rescue.

What if there were no viable “hard points” on the side of the tank to tie the securing ropes onto the ladder, thereby “pulling” the ladder against (towards) the tank? An alternative would be to tie opposing top guy lines onto the ladder, anchoring them to pickets or other secure anchors. This would prevent the ladder from sliding sideways against the tank wall during the rescue. This would be very similar to the tying of side guy lines onto a ladder in a ladder-as-a-derrick configuration. The bottom line is to prevent the ladder from shifting sideways while against the tank.

A 24 foot NFPA rated extension ladder is placed against the side of the tank with the tip above the victim’s head.

The next scenario we trained on was that of a man who had climbed up and around the tank access ladder guard in an attempt to ascend the ladder to the top of the tank. During his climb, his wet boots slipped off of one of the ladder rungs, causing him to strike his head against the ladder cage, rendering him unconscious. During his short fall, his leg and an arm wedged into the bars of the ladder guard and the ladder, causing him to become “wedged” in the ladder cage about 20 feet above the ground.

While there are several ways to effect this rescue, I had the rescuers utilize a “modified ladder assist”and standard lowering system technique, due mainly to the very tight area within the circumference of the cage around the tank ladder. Since the victim had the tank ladder completely blocked with his body, I had the rescuers ascend the ladder cage assembly using ladder hooks attached to their class III harnesses, much like you would use in a cell tower ascent, to get to the top of the tank.

There, they rigged a simple brake bar rack lowering system attached to a modified class III harness tied onto the victim. This knot used was the rescue knot, sometimes known as the “life basket,” which is a tied class III rope harness on the victim. In this situation, using a rescue knot class III harness, with the tie-in point at the victim’s chest level, the victim can more easily be lowered in a vertical position down through the cage and ladder structures.

The victim is received by rescuers on the ground.

A rescuer ascended the ladder from below the victim, and placed himself at the victim. The rescuer’s arms were on the ladder but under the arms of the victim, thereby helping support the victim’s weight and serving to keep the victim parallel to the ladder and cage during the rope-assisted ladder assist. Likewise, during descent, the victim’s legs straddled the rescuer’s legs. Therefore, at any given time, the victim was supported during descent at four places: on the rescuer’s leg (thigh position), under both arms, and at the lowering rope attached to the victim at chest level.

As the rescuer and victim approach the ground, rescuers assist by receiving the victim into their arms for proper patient packaging and transport away from the tank.

Common lockable guard on the vertical tank ladder welded to the tank.

Were there other ways to accomplish this rescue? Of course; there are usually several viable and efficient methods to perform a rescue. They could have raised the victim to the top of the tank and performed a lower outside of the safety cage. However, a rescuer would still have been needed to free the victim’s legs from the cage structure, and then to ascend with the victim during the raise to keep the victim’s arms, legs and head from becoming entangled in the safety cage. But consider this: why perform a raise of the victim the rest of the way up to the top of the tank, only to have to package the patient atop the tank for a complete lower back to the ground?

The bottom line here is this: keep the rescue simple, safe and efficient, as timely as possible, with as little chance of adding further injury to the victim or injury to the rescuer(s). That, my fellow rescuers, is rescue, plain and simple. It requires planning, skill and teamwork, just like any other rescues we perform. It involves patient-rescuer risk analysis. Then — just do it.

Until next time, study, train, train some more and be safe!

Bob Twomey is the current chief and founder of the North Carolina High Level Extraction Rescue Team, Inc., a volunteer helicopter search and rescue support team based in Transylvania County, N.C. He is the senior helicopter pilot for Wolf Tree Aviation, LLC operating out of Transylvania Community Airport. He also serves as Deputy Chief for Training in Brevard Rescue Squad. He has been active in SAR for 37 years. Twomey can be reached at 828-884-7174 or [email protected].
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