Ladder truck as ancor or déviation

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Permalink Reply by TrainingTECH1 on September 20, 2009 at 4:28pm

This is a tough question and I am sure you will get some folks saying its not safe. The technique is OK, but you need to know the limits of your equipment.

We do use our aerial for this application. Smeal is our manufacturer and the ladder has a special feature that was developed by our department for rope rescue applications.

We generally use a fixed system off the tip (short haul). However, we can set up a moving system. The key thing to remember is that a moving rope system should be used in-line with the ladder. That is the ropes should run either on the ladder bed, or directly under the ladder bed. If you must anchor to the truck itself, it is best to rig in a lcation where the ladder is perpendicular to the frame. Most manufacturers will install or have installed anchor points on the truck to accomodate this configuration.

When using the aerial some key safety considerations. Limit the load, know the capacity of the ladder, and never pull a load of center of the ladder (it torques the ladder and if the load and pull or heavy enough it could damage the ladder).

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Permalink Reply by Ben Waller on September 20, 2009 at 4:53pm

Some manufacturer rate their aerial ladders for use with rope systems and some don't. The ones that do not can still be used safety for rope rescue, but only within a specifically-designed system that does not exceed the tip rating of the ladder at the elevation, extension, and rotation at which it is set.

For the aerials rated for rope rescue, most are not rated for use as a crane (dead lifting). Some tower ladders and rarely, some straight sticks are rated for this, but they're the exeption.

The most important thing is to set up the aerial in a solid spot and to operate it only within the design specifications.
Once you do this, the rigging should always start with an anchor at the tip, a 2:1 Mechanical Advantage system rigged to the load, and a change-of-direction at the tip. This will cut the force of the lift (pulling force) in half and help keep the forces within the tip load rating. A second change-of-direction pulley should be rigged as close to the centerline of the aerial as possible. This can be rigged to anchor points built into the frame, the main trunnion on the base section of the ladder, or to an anchor extension run from the rig's frame.

If you're lifting a 500-lb load on an aerial with an 800-lb tip rating in the configuration in which it's set, the additional force you'll add is 250 lbs on the haul system side of the 2:1. However, that force will be directed down the aerial's long axis, so it will add minimal, if any force to the force of gravity trying to pull the ladder tip to the ground. Instead, the re-directed force will simply put the ladder box into compression...something that it's designed to do.

Don't shock load the rope system/aerial, keep the rope in the center of the aerial, and don't move the ladder tip while the load is suspended and chances are that you'll be OK.

A prerequisite is that everyone involved in this system must be trained in both the aerial ladder and rope systems. If the load is being lifted from water - especially swiftwater - the crew must be trained in that speciality as well. Otherwise, you're using a low-occurrance, high-risk rescue technique without training on it first, and that's a recipe for disaster, no matter the aerial ladder's rating.

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Permalink Reply by Dave Andrews on October 1, 2009 at 2:35pm

Tank's guys for your post...

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Permalink Reply by Doesn't play well with others. on October 1, 2009 at 5:33pm

Sure you can use a Tower Ladder or Aerial as an anchor or high point. Some food for thought;

How are you moving the the patient/rescuer from over the rescue point to the safe zone? Pulling on tag lines? Traversing, lowering, extending or retracting the aerial device? Most technical rescue education would frown on swinging an aerial around with a live load dangling from it. It is a very uncontrolled movement.

What is the load rateing for your aerial?

You mentioned water, is this moving water. The load you might put on the tip is actually up pretty high, as the moving water is causing drag on your patient/rescuer and loading up the system.

An anchor point adds some difficulties. Is the working end of your mechanical advantage going to be operated from on the groung or up in the basket? In the basket there is a very short throw area, and the number of people able to be in the basket works againts you after adding the load of a patient/rescuer.

Check this out; http://www.firefighternation.com/group/technicalrescue

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