1. #1

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    Default Tying forward rails used for change of direction & HVAC units as anchors

    When using hand rails as a change of direction during rope rescue (such as lowering a patient in a basket) do most of you reinforce the rail- or possibly not use rails at all.

    I have seen hand rails used for change of direction tied back (toward the anchor point), but that seems wrong to me. Shouldn't they be tied forward because of the direction of the force on the rail?

    Also, was wondering if there was a rule of thumb on using HVAC equipment as anchors on roof. All I've heard or seen in manuals is to use caution because most are not anchored to the roof. Was wondering if there was a cut off in size that is usually gone by IF using HVAC units.

    Thanks.

  2. #2
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    Fairfield's Avatar
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    The direction of force is the resultant. So for me if I was trying to tie in the opposite direction it would not truly be toward the anchor. Hand rails as a COD is a case by case judgement that I would make. What is the rail attached to? How old is it? What is it made of? What is my anticipated load going to be (not just the load on the end of the line but also the resultant force at the COD). All of these are things that will be needed to be thought about when coming up with your rigging plan.

  3. #3
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    Name:  forces.jpg
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    So in the picture ( I know not a hand rail) the force at the COD with 175 lbs load would be 196 lbs with this setup. The blue X would be going toward the direction of to me best tie back for the rail. Hope this helps answer your question or maybe make it visually clearer. As you can see though, the COD or railing stands the chance of having a greater force hit to it then what the load and anchor will see. So rig carefully.

    FWIW the formula for this is: cos{<(.5)} (2) (ans) (load)= resultant force
    Last edited by Fairfield; 06-10-2014 at 06:51 PM.

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