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DOE-STD-1090-96, DOE Standard Hoisting and Rigging Manual ...

DOE-STD-1090-96, DOE Standard Hoisting and Rigging Manual ...

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<strong>DOE</strong>-<strong>STD</strong>-<strong>1090</strong>-<strong>96</strong> (Rev-1)11.3.1.3 Design FactorIn general, a design factor of5:1 is maintainedthroughout this section. However, certain slingfittings, such as hooks (which will straightenwithout breaking) or links (which will deformbeyond usefulness before breaking) cannot beassigned a definite numerical design factor. Insuch cases, suitable safe loads are listed, based onwide experience <strong>and</strong> sound engineering practice.11.3.1.4 Sling CareProper care <strong>and</strong> usage are essential for maximumservice <strong>and</strong> safety. Wire-rope slings shall beprotected from sharp bends <strong>and</strong> cutting edges bymeans ofcomer saddles, burlap padding, or woodblocking. Overloading shall be avoided, as shallsudden dynamic loading that can build up amomentary overload sufficient to break: the sling.11.3.1.5 Sling StoragePersonnel using slings shall ensure that they arestored properly as follows:a. Slings should be stored in racks (preferablyvertical) <strong>and</strong> in designated locations when not inuse. Do not store slings in a location where theywill be subjected to mechanical damage, corrosiveaction, moisture, extreme heat, or kinking. Slingsmay require segregated storage as determined on acase-by-case basis.b. Before storage <strong>and</strong> periodically duringstorage, wipe slings clean to remove as much dirt<strong>and</strong> abrasive grit as possible <strong>and</strong> relubricate wirerope <strong>and</strong> chain slings to extend their useful life.Chains should not be lubricated when in use.c. Do not store metal-mesh slings in areaswhere the temperature exceeds 550 degrees F (288degrees C) or 200 degrees F (93 degrees C) ifelastomer covered.d. Do not store synthetic-web slings where thetemperature exceeds 200 degrees F (93 degreesC).11.3.2 Wire-Rope Slingsa. Ingeneral, wire-rope slings are made up of 6x 19 or 6 x 37 classification wire rope.Rotation-resistant wire rope shall not be used forwire-rope slings. Different kinds ofslings havebeen developed for specific purposes. These aredivided into different groups or types as follows:1. Endless-loop slings (grommetconstruction) <strong>and</strong> single-part slings withsingle-rope legs, double-rope legs, ormultiple-part rope legs.2. TWO-leg bridle slings with single-ropelegs, equalizing double-rope legs, or multiple-partrope legs.3. Three-leg bridle slings.4. Four-leg bridle slings.5. Special slings <strong>and</strong> combinations.b. The total load that can be safely lifted withslings depends on the rating ofthe slings <strong>and</strong> themanner in which they are attached to the load.Consult (load) Tables 11-4 through 11-9 <strong>and</strong>Figure 11-10.c. Braided slings are made by braiding ordinarywire ropes together, thus making them moreflexible than wire-rope slings. The size of abraided sling is determined by the diameter of onewire rope <strong>and</strong> the number ofropes in the crosssection ofthe sling.d. The design factor for wire-rope slings shallbe a minimum of5:1 based upon breakingstrength.e. When a wire rope sling is used in a chokerhitch, the normal angle formed in the rope body asit passes through the choking eye is 120 degreesor greater [do not confuse the choke angle with theangle ofinclination ofthe load (see Figure11-10)]. Rated load in load capacity Tables 11-4through 11-9 are for angles of 120 degrees orgreater. For smaller angles, reduce the rated loadto the percentages given in Figure 11-10.Chapter 11Wire Rope <strong>and</strong> Slings 11·10

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