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Winch Rigging Assembly Safety and Use Regulations

Winch Rigging Assembly Safety and Use Regulations

(OP)
I am wondering what regulations may exist for the safe use of rigging assemblies used in winching.

I have a device that needs to be pulled horizontally out of the earth. There are no attachment point on the is device so something will need to be designed and built for this purpose. I am wondering what regulations exist for the design and use of a custom rigging assembly and attachment such as this. I am aware of the OSHA regulations for "Rigging equipment for material handling" in 29 CFR 1926.251(a)(4).

"Special custom design grabs, hooks, clamps, or other lifting accessories, for such units as modular panels, prefabricated structures and similar materials, shall be marked to indicate the safe working loads and shall be proof-tested prior to use to 125 percent of their rated load."

The problem here is that the "rated load" is unknown. In a typical hoisting situation the weight of the device being lifted is know and can be used as the maximum rated load. With a device that is stuck in the earth and needs to be pulled the force required to do this is unknown. I suppose in this situation the maximum pulling force of the winch could be used a rated load to design against.

But what I am really wondering is what safety standards exist. The OSHA standard I referenced seems to not apply to winching because the following paragraph states that the scope of this standard "... applies to slings used in conjunction with other material handling equipment for the movement of material by hoisting ..." 29 CFR 1926.251(a)(5) and "hoisting equipment" is defined by OSHA as "equipment designed to lift and position a load of known weight to a location at some known elevation and horizontal distance from the equipment's center of rotation. 'Hoisting equipment' includes but is not limited to cranes, derricks, tower cranes, barge-mounted derricks or cranes, gin poles and gantry hoist systems. A 'come-a-long' (a mechanical device, usually consisting of a chain or cable attached at each end, that is used to facilitate movement of materials through leverage) is not considered 'hoisting equipment.'" 29 CFR 1926.751

I've discovered 29 CFR 1917.47 it has nothing about rigging and seems to apply only to marine terminals.

RE: Winch Rigging Assembly Safety and Use Regulations

If there is no specific OSHA requirement, there is always the General Duty clause that OSHA can use to cite employers. I would say do a job safety analysis and there are many example on the WEB that can guide you and use that to evaluate the safe procedures. Also have your engineering staff do all the calculations relevant to this job and keep that available in case you are questioned by OSHA. I remember that I had to provide OSHA with my drawings of lifting beams that we had made in our shop.

RE: Winch Rigging Assembly Safety and Use Regulations

"I would say do a job safety analysis. . . " Yup
And calc out and document your rigging plan - look for examples of "Safe Rigging Plan". You are making a 'lift', it just happens to be in the horizontal direction. As far as 'weight', make sure that the pulling device has a clutch that prevents overloading [or some other safety] - otherwise the structural limit of the rigging can be exceeded and a catastrophic failure* is possible.

*Catastrophic failures on winching typically causes the pulling rope - wire cable - to release elastically, whip across the plane of the lift/pull, and shatter/amputate the legs of anyone in the rope's path. I personally have seen a failure whip a 5/8" cable/wire rope into a semi-truck front end and destroy the hood, radiator, alternator, etc. Winch operator was prudently behind something sturdy, and was lucky. The cable could have struck what he was sheltering behind, whipped around it [like Indiana Jones's bullwhip] and destroyed him.

RE: Winch Rigging Assembly Safety and Use Regulations

Witch rope failure, hook failure, or mounting point sudden failure aside, the rest of the apparatus is somewhat "safer" than under an overhead lift. Even a slowly-yielding hook or bending or twisting mounting bracket is going to be much, much less danger than a sudden rope failure.

The good news is, true, you don't know how load (either breakout resistance or steady-movement-pulling resistance) but a horizontal pull failure means the loads stops, rather than accelerates down unto people or into things.

Your maximum force is going to be not the design strength of the winch-mount+winch+rope+hook+load-mounting system, nor 1.25 x the smallest rated capacity of the system, nor the ultimate strength (immediately before failure) of the winch mount + winch + rope + hook + load mounting method. Rather, it will the lowest ultimate single one of that long combined string starting from from nuts and bolt holes on one side to nuts and bolt hole in the final piece. Test to failure each major component, rate your system basem based on that breaking load: with margin and safety factor multiplied in obviously.


Consider a warning wire or string like what is used on Kevlar hoist straps: It stretches less less than the kevlar strap, so, when the string goes taunt, the kellar still has not stretched far enough to yield.

RE: Winch Rigging Assembly Safety and Use Regulations

Looking at similar appliction for horizontal drag of waste. Controls to put in place are reliable overload cut out switch, so the cable cannot be overloaded to break point. Also consider if the cable/attachment point/hook does fail what will be the trajectory of hte cable as it springs off the load. Control the work place so there are no go areas directly behind the winch or along side teh drag path. People have been killed by broken cable/rope wipping past them.

Mark Hutton


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