Extrapolating Default WLL for Unmarked Steel Strapping?

Discussion in 'Flatbed Trucking Forum' started by WadeH, Mar 20, 2020.

  1. WadeH

    WadeH Bobtail Member

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    A company "unitizes" building material (metal roofing and siding panels) into bundles using unmarked steel strapping that is 3/4" x 0.023. I have contacted the supplier of the strapping to get the WLL, but they have declined to share the information.

    FMCSA Cargo Securement Rules says: "Steel strapping not marked by the manufacturer with a working load limit will be considered to have a working load limit equal to one-fourth of the breaking strength listed in ASTM D3953-97..." which I don't have.

    The same Securement Rules also gives a table of some "default WLL" of steel strapping, including this one: 1-1/4" x 0.029 = 1,190 lbs.

    I need the WLL for unmarked steel strapping that is 3/4" x 0.023 so I can try to figure out if the bundles are unitized such that I can secure each bundle as an individual item.

    So I'm wondering if I can I extrapolate the WLL from a strap that is listed in the table and dependably rely on that WLL for securement purposes?

    This is how I worked it out. I used the cross-section of the strapping from the table (1-1/4" x 0.029 = 0.0362) and the cross-section of the sample strapping (3/4" x 0.023 = 0.0172). Then I solved for the WLL of the sample strapping "x" lbs. like this:

    0.0362 / 0.0172 = 1,190 lbs. / "x"
    x = 565.4012 lbs.

    Is this a valid approach?
     
  2. Old Man

    Old Man Road Train Member

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    Unless you’re using steel strapping to tie a load to your trailer, wll doesn’t matter.
     
  3. kylefitzy

    kylefitzy Road Train Member

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    Bingo! As long as the strapping has sufficient strength to unitize the material, ie it doesn’t break, you’re good. That’s just my opinion though.
     
    cke Thanks this.
  4. WadeH

    WadeH Bobtail Member

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    So here's a photo of a unitized bundle. If the steel strapping is strong enough, can I just run fabric straps through the lower layers and then the top layers are also secure? Or regardless of steel banding strength, must fabric straps be placed over the top of the bundle anyway?

    Usually each individual skid is banded to both the skid below and above it (but not so in this example). This makes one large unitized bundle. These are LTL deliveries and by fabric strapping at the bottom, then only the steel strapping needs to be cut in order to remove the top skids at each delivery. Photo of securement straps on unitized bundle-cropped 2.jpg
     
    Last edited: Mar 21, 2020
    Reason for edit: clarification of photo
  5. Claytonbigsby

    Claytonbigsby Bobtail Member

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    Why wouldn’t you want to add 3 straps across the top in addition?
     
    beastr123 and kylefitzy Thank this.
  6. cke

    cke Road Train Member

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    Strap over the top and be done with it
     
  7. npok

    npok Light Load Member

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    Looking at that pic & what OP wants to try, I don't think that 3 wraps of banding comes anywhere close to meeting the .8g deceleration & .5g lateral requirements.

    You could just unwind your top straps at each stop & the forklift can pull layers out from under the straps. That would at least save you having to roll up & throw straps back over.

    That is unless the tin would tear up the straps.

    Another thing to think of is "How would I make DOT believe this?". You could get in some hot water for something perfectly legal just because it doesn't look right to an officer.
     
    Last edited: Mar 21, 2020
    Reason for edit: Add to post
  8. Old Man

    Old Man Road Train Member

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    I would put straps where the banding is, they will pull down on the dunnage and hold better.
    Get a rubber mud flat for protection, to make each stop easier cut your straps to length, no excess to secure and they’ll tighten quicker.

    If the pieces are over 10 ft long put a strap over the middle to keep dot happy.

    the way they are loaded in the picture I don’t think you can get a good enough pull on them to keep them from sliding on the aluminum deck. Friction mat would help.
     
    jamespmack Thanks this.
  9. mud23609

    mud23609 Medium Load Member

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    Even if you can is it worth the extra scrutiny from the dot? Looking legal is just as important as, if not more important than being legal in our line of work.
     
    npok Thanks this.
  10. Tug Toy

    Tug Toy Road Train Member

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    I never have nor will I ever trust banding.

    That stuff is as worthless as plastics wrap in the flatbed world in my opinion. Seen way to much of it broken before it even goes on the truck.
     
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