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Help wanted please -- Safety margin of a Rigger's harness

  1. Jan 15, 2015 #1
    Hi All, I am a rigger and it's my job to climb and be suspended from aluminum tube that is 4mm thick, for my new assignment.
    All of my fall arrest equiptment has to be rated for 22kn ( that's the load associated with a fall into a fall arrest device).
    The place I am working can't give me a clear value of the tubes breaking strength, so I am wondering if anyone knows if this 4mm tube will take a shock load of 5000lbs (22kn), my life kind of depends on it!!
     
  2. jcsd
  3. Jan 15, 2015 #2

    berkeman

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    Welcome to the PF.

    What country are you working in? In the US, OSHA has some pretty strict safety rules and standards. You shouldn't have to be wondering if the safety equipment that you are supplied with for your work is adequate.
     
  4. Jan 15, 2015 #3

    berkeman

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    BTW, a 4mm tube is quite small. Are you sure that it the size? Can you post a picture of the whole arrangement?
     
  5. Jan 15, 2015 #4
    Hi, I live in Canada., and you would be suprised how little my trade is regulated., sadly I can't send pics, I build and test radar and military sattalite dish's, so not allowed pics.,
    The tube wall is 4mm thick, the tubes themselves vary on O/D, max is 4.5 inch O/D., I'm an experienced climber so I have back up fall arrest equipt back to the tower, but it is very cumbersome to use, so I am wondering if the tubes will hold.. Lol
     
  6. Jan 15, 2015 #5

    berkeman

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    It looks like the corresponding agency in Canada is the Canadian Centre for Occupational Health and Safety http://www.ccohs.ca/

    Even if your particular industry is not well-regulated, you can look at what the rules and guidelines are for similar occupations with respect to climbing safety harnesses and equipment. I'm guessing you can get good answers by looking at what other folks do in situations similar to yours. That's really the best way to go on safety questions like these -- find out from experts in the related fields. You could give them a call with your question using the advice phone number on that web page, for example. :-)
     
  7. Jan 15, 2015 #6
    Hi, thanks. I know the facility that you sent me, trouble is, as soon as you make an inquiry, there is a target on you for causing an issue..,
    I have the gear to do a pull test on these tubes, I will just wait for spring and keep the back up system in place.
    Thanks for your input!
    Cheers!
     
  8. Jan 15, 2015 #7

    Bystander

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    Ever see signs of corrosion? Salt? Used bird seed?
     
  9. Jan 15, 2015 #8
    Not really, these antennas are new, we test them prior to shopping them out. But for sure lots of bird droppings on the tower, but it's pretty sturdy steel guyed tower., as for corrosion, minimal.
     
  10. Jan 15, 2015 #9

    Bystander

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    So the Al is part of the rigging, and stored where it's not exposed to too much in the way of corrosive influences. That was all I had to throw in.
     
  11. Jan 15, 2015 #10
    Hi, it's actually what the boom ( the horizontal piece) and the reflector ( vertical dish part) are made of., the boom is @ 34 feet out from the tower , and the reflector is @ 40x60 feet., I have noticed a fair amount of deflection when I walk out on the boom to make adjustments to the electronics and wave guide, but it is far from corrosives
     
  12. Jan 15, 2015 #11
    Soft stops greatly reduce the shock. Do you have one available to use?
     
  13. Jan 15, 2015 #12
    in Canada the guidelines are as strict as in the US. when you use a harness you must have a hard connection point in many cases we'd use a strap around a connection joint where a few smaller elements are joined then connect the drop line we attach the snap stop to. if your walking out between two structures the safest is always a span line between both to clip the snap stop on. if your on huge sat dishes isn't there a steel cable between the center and the end of the walkway? similar to the attach line on suspended bridge cables. those are for direct connecting the harness.
     
  14. Jan 15, 2015 #13
    The short of it is this: your company has to ensure that the tie point is capable of withstanding a 5000 lb force at the point of anchoring, that means having a professional engineer or at least a competent person verify that the tie-point is adequate. You should read through the codes and your province's workers' rights, in the U.S. (and I'm pretty sure in Canada as well) no worker is forced to work if the conditions are unsafe, especially regarding working from heights. Your company is opening itself up to a huge liability by not verifying the tie point. If a worker falls and is injured or killed, the investigation will be a quick one for sure if they have no documentation showing that the anchor point was sufficient.

    Determining whether it is safe for you to do work on this surface should not be left to you, and I don't think anyone on this site will be willing to, or even should, offer you an analysis one way or the other.

    With that said, it's a matter of geometry, not only material. As I said, I don't think anyone should give you the green light, but perhaps if you gave more information on the geometry of the beam, someone could at least indicate whether the beam is dangerously insufficient.

    Also, what's the distance between the walking surface and the nearest obstacle (the ground, other beams, etc?)

    edit: BTW, by competent person, I'm using the industry meaning of someone with adequate training, education, professional designation in the necessary field(s) in order to make an informed decision. This would generally be a safety manager, structural engineer, foreman, etc.
     
  15. Jan 15, 2015 #14
    From this post
    it seems the rigger would want to bypass the established safety regulations of the government and the company.

    anchor points need to be certified by a professional engineer as being safe and adequate.

    Using other parts of a structure to connect a restraint or arrest system, without certification or authorization from the company or professional engineer, the case may be, then involves transferring a greater percentage of the liability to the employee ( acting on his own ).

    It is no wonder that the place of work will not authorize use of the tubes - they are following regulations.

    Regulations are there for an employee's protection.
     
  16. Jan 15, 2015 #15
    having spent many months at a time in full fall gear on highrises and other structures some tie points can be left up to the worker to chose but the criteria is pretty universal.
    rule of thumb: any question that it may not meet the strength reqs. means it doesn't pass. in structural steel work you strap around beams or posts in a way that no additional downward motion can occur. the fall resist ropes must be in a way that you do not exceed a ten foot fall which includes the length of your lanyard. less if the ground is only ten feet down. some lanyards are sown to create a slow let out from 3' to 5' to reduce the shock of reaching the end of the tether.
     
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