RH : Chain Block & Safe Working Intruction

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Chapter:- Rigging & Hoisting

Chain Block & Safe Hoisting

HAND-OPERATED CHAIN PULLEY BLOCK is commonly used for lifting heavy materials / loads, reduces human effort in lifting.

There exist many hazards when lifting loads, particularly when the chain block is not used properly or is poorly maintained. Chain pulley block needs to be inspected before usage.

The basic objectives of any lifting operation are to move the load to the desired location and land it safely, efficiently and without damage to the load, the equipment used or the surrounding buildings, plant etc.

Points to be checked in Chain pulley blocks before use:

Hooks

• Inspect hooks for signs of opening, cracking, bending, arc burns and corrosion.
• Hooks should swivel freely.
• Inspect safety latches for condition & operation.
• Measure the hook throats for allowable service openings.

Hand Chain

• Inspect chain for wear.
• Inspect chain for twisted or gouged links and corrosion.
• Inspect connecting link for signs of opening.

Load chain

• Inspect chain for wear.
• Inspect chain for gouges, nicks, arc burns, twisted & bent links and corrosion.

General

• Inspect frame and covers for distortion, cracks, gouges, corrosion & other damage.
• Inspect hangers for cracks, gouges, corrosion & other damage.
• Ensure that the chain pulley block has a valid third-party certificate.

Safe Use of Blocks

1. Never attempt lifting operations unless you have been trained in the use of the equipment and slinging procedures.  
2. Position the hook directly over the center of gravity so that the line of pull is vertical.
3. Do not use the chain/wire rope to sling the load, i.e. do not wrap it round the load, back hook or choke hitch.
4. Do not lift on the point of the hook or overcrowd the hook with fittings.
5. Never lift or lower, more than the marked SWL. In the case of manual equipment, if abnormally high effort is required and with power operated appliances they fail to lift the load, or if the load slips this is an indication of too high a load or a fault - check the load and the appliance.
6. Avoid unnecessary inching of power operated appliances and do not impose sudden or shock loads.
7. Push rather than pull loads suspended from appliances with push/pull trolleys and if un-laden pull on the bottom hook. Never pull an appliance by the pendant control, suppl cable or hose.
8. Avoid sudden movement of travel motion or undue effort in pushing the load which can cause the load to swing.
9. Avoid excessive or intentional use of motion limits unless they are additional limits intended for that purpose. Avoid running appliances against end stops.
10. Do not allow anyone to pass under or ride upon the load. Never leave suspended loads unattended unless in an emergency then ensure the area is cordoned off and kept clear. 
11. Do not remove guards, protective covers.

SAFE WORKING INSTRUCTIONS FOR USAGE OF CHAIN SLINGS AND CHAIN PULLEY BLOCK

• At the beginning of work, check slings and hooks for defects, dirt and grit. Give special attention to slings to which the hooks or rings have been added to make certain they are secure.
• When raising / lowering the load, see that it safely clears adjacent stockpiles.
• Never use a sling that has stretched or a hook that has begun to straighten. When permanent set of the hook is greater than 15 % in excess of normal throat opening, replace the hook.
• Distribute the load equally on the legs of a sling. As the angle of the leg increases from the vertical, the Safe working load of the chain pulley block decreases as given in the figure.
• See that the slings are not kinked, twisted or knotted.
• Make sure that the load does not exceed the rated load capacity of the chain pulley block at various angles of the sling with the vertical.
• Center the chain pulley block directly over the load to prevent the load from swinging when it is raised. Be sure the load is balanced.
• While hooking or unhooking a load, keep hands out of pinch points.
• Do not leave separator blocks or short lengths of steel on top of a load.
• Whenever possible, walk ahead of the moving load. See that it is carried high enough to clear all obstructions.
  
• Do not drag, throw or drop slings.
• Never splice a chain by inserting bolt between two links.
• Never put strain on a kinked chain. Workmen should be trained to remove the slack slowly and see that every link in chain sets properly. 
• See that the load is always properly set on the bowl of the hook.
• Do not use hammer to force a hook over a chain link.
• Chains not in use should be stored in suitable rack.
• Do not carry load over men on the floor.
• Do not allow men to ride on a load or on crane hook.
• Never pick up a load beyond the rated capacity of the crane.
• Do not allow the load swing against floor men.
• Damaged hoists must be removed from service.
• Chains should not be replaced, lengthened or spliced.
• Chain pulley block should be calibrated for its rated load once in a year and the test certificate has to be obtained from a competent person and maintained.
• The supporting structure (load hook) to which hoist is attached must have sufficient strength to support the load.

DO’s and DON’Ts while using Chain pulley blocks:

Do’s

• Check the structure of hook supporting the chain block has adequate strength.
• Ensure minimum Factor of Safety ‘3’.
• Ensure to isolate / barricade the work area where lifting operation is on-going
• Make sure that the load is free to move and clear all obstructions.
• Confirm that the brake is functioning properly by hoisting the load to 100mm and check the brake when lowering the load.
• Make sure all persons stay clear of the suspended load.
• Protect load chain from weld spatter or other damaging contaminants.
• Use chain blocks with hook latches.
• Regularly clean the whole length of load chain as recommended.
• Avoid swinging of load while hoisting.

Don’ts

• Don’t run the load chain out too far, when operated beyond the range of lift, an excessive load will be imposed on the chain block.
• Don’t lift a load in excess of safe working load of the chain block.
• Don’t walk or work under a hoisted load and never lift, support or transport people.
• Don’t leave a load hanging on the chain block.
• Don’t use damaged equipment, the same must be sent for servicing/repairing.
• Don’t lift with the point of the hook and never use the load chain as a sling by back hooking.
• Don’t operate unless load is centered under hoist.
• Don’t allow the chain or hook to be touched by a live electrical cable / welding electrode.
• Don’t adjust or repair a chain blocks unless qualified to perform.
• Don’t attempt to lengthen / modify the load chain, load hook or repair damaged load chain.