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NSC LOAD SECUREMENT.pptx

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					       NSC LOAD SECUREMENT
Cargo Securement standards require that all devices and systems used
 to secure cargo to or within a vehicle must be capable of meeting the
      performance criteria. All vehicle structures, systems, parts and
   components used to secure cargo must be in proper working order
when in use. This means that they cannot be damaged or weakened so
     as to affect their performance. The cargo securement standards
     reference manufacturing standards for certain types of tiedowns
    including steel strapping, chain, synthetic webbing, wire rope, and
                                  cordage.
                          Proper Use of Tiedowns
  Each tie down must be attached and secured so that it doesn’t come
 loose, unfastened, opened or released while the vehicle is moving. All
  tiedowns and other components of a cargo securement system must
       be located inside any rub rails whenever practical. Also, edge
    protection must be used whenever a tie down would be subject to
  wear or cutting at the point where it touches an article of cargo. The
          edge protection must resist wear, cutting and crushing.
                         Use of Unmarked Tiedowns
        Current standards prohibit the use of unmarked tie downs.
                   Unrated and Unmarked Anchor Points
These cargo securement rules do not require the rating and marking of
 anchor points. While manufacturers are encouraged to rate and mark
    anchor points, the new rules do not include this as a requirement.
      WLL sometimes is called safe working load

•   Working Load Limit(WLL):

•   The maximum load that may be applied to a component of a cargo
    securement system during normal service, usually assigned by the
    manufacturer of the component, for different kind of tie down devices,
    the ways to apply load are different, for instance, the WLL of grade 70
    transport chain is the maximum load shall be applied in direct tension to
    an undamaged straight length of chain.
    Working Load Limit determined by Design Factor(DF) and Minimum
    Breaking Strength(MBS) of specific tie downs, MBS divided by DF is the
    WLL of the tie downs:
    WLL = MBS/DF
    For 3/8'' grade 70 chains, the DF is 4:1, MBS is 26400LBS, thus the WLL is
    6600LBS.
    Sometimes people use Safe Load Limit in place of WLL.
    The typical working load limit of tie downs:
    1'' tie down straps have the most variations, because people use 1''
    straps in all kinds of applications;
    2'' tie down straps have typical working load limit of 733lbs, 1000lbs and
    3333lbs;
    3'' tie down straps have typical WLL 5400lbs;
    4'' tie down straps have typical WLL 5400lbs;
         A LITTLE PRE-CHECK
When tying down and binding loads please follow following
guidelines:
• 1. Maintain secure footing at all times, check for loose spots
    periodically.
• 2. Inspect tie down device before use. Do not use hooks,
    shackles, links, clips, chain, and other equipment
    components that are bent, elongated, gouged, nicked,
    excessively worn, or damaged. Make certain that nuts, bolts,
    pins, and other fasteners are tightened and secured.
• 3. Follow DOT Regulations, and Commercial Vehicle Safety
    Alliance Cargo Securement Tie-Down Guidelines.
• 4. Do not exceed the working load limit of tie down
    equipment. Refer to literature by grade for specific working
    load limits.
• 5. Center load in hooks, shackles, rings, and other such
    equipment components. Use spacers on bolts and pins as
    necessary to maintain center loading.
• 6. Do not apply load to hook latches; latches are to retain
    slack slings and chains only.
• 7. Avoid sudden jerks when applying the load. Rapid load
    application can produce overloading.
• 8. Free all twists, knots, and kinks. Apply load in a straight
    line fashion.
• 9. Refer to specific instructions when applying load binders.
    Observe warnings and stand clear of binder handles at all
    times.
• 10. Use only alloy chain and attachments (Grade 80, grade
    100 and grade 120) for overhead lifting.
• 11. Inspect load periodically for securement.
             A Lesson in Math
TOTAL POTENTIAL LOAD




•   Total Potential Load (TPL) is the weight to be lifted, towed,
    restrained, suspended, or secured, not just in a static
    condition, but in a dynamic condition.
•   Examples: the jerking of a weight being lifted, the heaving of
    a vessel, the slalom of a water skier, the falling of a body,
    the swaying of scaffolding, the tethering of a balloon, the
    wind pressure on antenna guys, a truck being towed out of
    the mud, and a boat being towed through waves, the loads
    on a flat bed truck on the move - these and many other
    situations like them produce dynamic forces with a total
    potential load that may well exceed, sometimes significantly,
    the static weight of the load, and this must be taken into
    consideration.
•   For example, a 10,000lbs backhoe on the flatbed truck held
    by 4 3/8'' grade 70 transport chains and 4 3/8''-1/2'' ratchet
    load binders will have total potential load much more than
    10,000lbs, imagine a sudden brake, a sharp corner turn or
    even an unfortunate event such as crashing into something
    rigid and big. This is the reason why the aggregated working
    load limit of all tie down devices(in this case 4 3/8'' grade 70
    binder chains) has to equal to or greater than half of the
    weight of the load, and since these chains and binders has
    design factor of 4:1, so the properly secured tie downs can
    sustain forces 4 times of the aggregated working load limit,
    which is 6600lbs x 4 = 25,600lbs, theoretically 4 chains
    together can sustain 25,600lbs x 4 = 102,400lbs total load.
special anchor points
special anchor points
special anchor points




         Proof Test

         The Proof Test (manufacturing test
         force) is a term referring to the
         minimum tensile force which has
         been applied to a chain, binder or
         rope under a constantly increasing
         force in direct tension during the
         manufacturing procedure.
special anchor points
            special anchor points



•   Chain Grade and Size The minimum size chains suggested for most
    commercial hauling operations is a Grade 70 (G70) chain. This chain
    type has a load limit from 3,100 lbs to 11,300 lbs depending on the
    chain link size. But the actual Working Load Limit, or WLL, of a
    binder assembly depends on other factors, most importantly the
    connecting mechanism on the end of the chains. Most popular for
    commercial trucking operations is a simple steel hook. The method
    of attachment affects the WLL. A hook forged to the end chain link
    supports a lower WLL than a clevis style pin connection. Typically a
    clevis pin connection will carry fifty percent more load. Better still is
    the use of a heavy duty ratcheting binder which can support the
    highest load levels and approach the limit of the G70 chain itself.
    Ratchet or Level Binders have working load limits of 6,000 lbs to
    10,000 lbs depending on size.
special anchor points
Think Better Not Okay
 Load binders are valuable construction tools, however,
there are safety hazards that may arise with their misuse.
    There are two types of load binders: ratchet type
             binders and lever type binders.

				
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posted:3/23/2014
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