Cranes

Introduction 

A crane is tall and big equipment which can lift heavy materials and transfer short distance.

    Lifting machine / equipment means a crane, crab, winch, pulley block, gin wheel, transporter or runway.

Cranes should be tested before use by competent engineer after major repair, at regular intervals. For tall tower cranes that are subject to excessive wind loads or to buckling danger, they should be adequately braced. Adequate ground support must be maintained before any lifting is done. For mobile cranes packing to spread load at the footing should be carried out. For tower cranes the pile cluster below the tower must be adequately designed. 

    Mobile Cranes are versatile material handling equipment, used for all outdoor jobs of handling heavy weighed to great heights. These are used in construction, erection jobs, storage yards, warehouse and ports.

Definition

• Crane: Crane consists of a mechanical rotating structure for lifting and lowering horizontally on rubber tires or crawler treads.
• Hoist: Hoists are used to lift and lower load.
• Boom: An inclined spar, strut, or other long member supporting the hoisting tackle.
• Boom stops: A device used to limit the angle of the boom at its highest position.
• Brake: To slow or stop motion by friction or power.
• Block: Sheaves or grooved pulleys in a frame with hook, eye and strap.
• Jib: Extension attached to the boom point to provide added boom length for lifting specified loads.

 Types of Cranes

1. Telescopic Cranes.
2. Overhead Gantry Crane.
3. Mobile Cranes.
4. Tower Cranes.
5. Truck Mounted Crane.
6. Rough Terrian Crane.
7. Loader Crane.
8. Floating Cranes.
9. Crawler Cranes.
10. All terrain Crane.
11. Level Luffing Crane.
12. Telescopic Handler Crane.
13. Aerial Crane.
14. Railroad Crane.

Major causes of Crane Accident

• Crane rigging failures. (i.e., steel wire rope, wires support, etc.).
• Crane mechanic failures (i.e., hydraulic failure, etc.).
• Cranes colliding with other buildings, structure, items, etc.
• Cranes colliding with energized power lines.
• Cranes hitting people with heavy materials and objects.
• Cranes dropping heavy materials and objects.
• Cranes overturning.
• Boom collapse.
• Crane hook-lifting device failure.
• Improper crane selection.
• Instability: It is unsecured load, load capacity exceeded, ground not level, too soft beyond the radius and boom angle, etc.
• Stormy, rainy, windy, rough, etc. poor or unsuitable weather condition.
• Improper crane set up (i.e., out of reach, Drag loads, Side-load a boom, etc.).
• Failing to comply with manufacturer specifications for crane use.
• Lack of communication: It occurs when the point of operation is at a distance from the crane operator or not in full view of the operator.
• Lack of training.
• Inadequate maintenance or inspection.
• Bypass the functioning Systems.
• Modify or ignore safety devices.
• Many more not included here.

Crane Hazards

• Improper load rating.
• Excessive speeds.
• Inadequate communication or hand signals.
• Inadequate inspection and maintenance.
• Unguarded parts.
• Unguarded swing radius.
• Working too close to power lines.
• Improper exhaust system.
• Shattered windows.
• No steps/guardrails walkways.
• No boom angle indicator.
• Not using outriggers.
• Inactive Limit Switch/ Asli/boom Over Hoist switch.
• Inexperienced and over experienced operator, rigger.

Safe Operation

• Training of crane operation for full knowledge of mechanism, controls, safe operation, testing and inspection.
• Transportation of the crane.
• Site of operation and crane positioning.
• Access the load, select the reach lifting capacity.
• Proper slinging-balancing of load.
• Cordoning the area.
• Free lifting (vertical) or loads.
• Stop operations in stormy / rainy weather and lock the crane.
• Fix responsibility for signaling to the crane operator.
• Ensure food housekeeping.
• Free operations and testing of brakes.

Precautions

1. All lifting equipment should be load tested by competent engineers before use and the designated safe working load (SWL) should be stamped on the equipment.
2. All lifting machine as hoists, lifts, cranes, etc. should be provided with safety devices to prevent over loading.
3. Regular inspection maintenance should be scheduled.
4. Standard signals should be implemented.
5. The crane operator shall have two licenses.
6. Heavy vehicles license.
7. Crane operator license.
8. Worker should not be allowed to stand under suspended loads and operator should avoid swinging loads.
9. The safe operation of such devices relies on a co-operation team of work between the operators of the much lifting equipment and the worker who secure the load to the lifting machine.
10. One person should be designated as signalman, he is called Rigger. He should be thoroughly acquainted with the standard hand signals.
11. The operation of the lifting equipment converts method of securing, handling, stacking loads and should be completely responsible for arranging the slings, “D” shackle and giving that direction to lifting equipment operator during the moving of the load.
12. Only authorized person and competent should operate the crane.
13. The correct sling must be used for the load to be lifted. The load must be within the safe working load (SWL) marked on the slings.
14. While lifting the load you must know the SWL of the crane. Never lift excessive load.
15. The loading hook should be in the center of the load lifted.
16. Never drag the load with the help of the crane to bring it under the loading hook.
17. The leg angle of sling should not be >90 because it increases the tension in legs.
18. Never lift the load with a sudden jack.
19. Never lift the load with the point of a hook.
20. Never use bolt and nuts to join broken chain.

Dos & Don’t s for Crane Operator

• Never use a crane which is under repair.
• Check all the controls starting the work.
• Never use more than two controls at a time.
• There before moving that slinging is alright by lifting the load about a foot from ground.
• Never leave the workplace while crane is in operation.
• Never leave any tools or work pieces lagging on the crane or trolley while moving load from one place to another.
• Never stand under the load being lifted.
• Crane operator should have two licenses,
  • Heavy vehicles license.
  • Crane operator license.
• Use required PPEs.
• Never lift compressed gas cylinders with crane.

Safety Devices of Crane

1. Over hoist limit.
2. Limits for trolley (for tower cranes) only.
3. Overload warming or cut-off.
4. Automatic safe load indicators
5. Angle radius indicator coupled with various loads at each radius.
6. Load charts.

 

Instructions for Crane Lift Plan

        Lifting with crane is always very risky and requires all mandatory safety precautions before the lifting activity proceeds. The following are some instructions that could be very helpful for the personals who involved in the crane lifting.

1. The use and Planning Process for crane lifting has two major categories:
   1. Crane Lift Plan.
   2. Daily Safety Review for Crane Operations.
2. A Crane Lift Plan is required for every crane lift on each project where the Lifting is required.
3. Where Critical Crane Lifts Operations involved, then only if authorized, may have to be reviewed by a Lifting professional engineer.
4. Submission for the Crane Lift Plans must be done at least 48 hours before crane mobilization. If helicopter or critical lifts involved, then for this purpose we need to submit Crane Lift Plan before-5 days.
5. Crane Lift Plans (CLP) must be based on worst case percentage of capacity (for example, gross deductions/chart capacity) for each particular crane configuration, location and activity (e.g., unload a delivery truck is a separate activity from erecting steel structure).
6. The Crane Lift Plan (CLP) may be valid for more than 1- day, as long as the configuration, location, and parameters used for Establishing “worst case” condition have not altered. Multiple Lift Plans (MLP) for multiple lifting locations/areas/projects.
7. All rigging devices/machinery must have the name of the Lifting Machinery/Devices manufacturer and identify Working Load Limit (WLL) and be certified as to their capacity
8. Where Custom-Fabricated Devices exists such as lifting beams, spreader bars, etc., may be acceptable with appropriate Professional Engineer (PE) stamp or proof testing as needed by lifting applicable standards. Lifting and WLL Capacities shall be marked and legible on all such devices.
9. Other worksite activities and the work that is not foreseen in the Crane Lift Plan (CLP) but may arise due to worksite conditions such as moving of various equipment, devices or machinery, loading & unloading materials/substances onto floors, etc.) must be reviewed with Organization in advance. Other Changes affecting crane configuration and/or location may need the Crane Lift Plan (CLP) to be amended.
10. The Main-Contractor/Sub-Contractor is accountable to visit the site before the lift date to review crane setup location and documentary information referring to the worksite, which is maintained by Organizations. The subcontractor is accountable (determining adequacy, supplying and installing) for all supporting material mandatory for the crane lift.
11. The Subcontractor is responsible to obtain all information that is necessary to develop a power line safety plan.
12. The Subcontractor is accountable to train all workers involved in the use of the crane, for example:
    1. Rigging.
    2. Signaling.
    3. Crane Operation.
    4. Assembly / Disassembly.
13. The Main-Contractor/Sub-Contractor must provide the following information along with the Crane Lift Plan (CLP):
    1. Competent person designation forms for Rigger operation Signal Person.
    2. Rigger and Signal Person training certification.
    3. Jurisdictional Registration.
    4. Risk Assessment (RA)/Job Hazard Analysis (JHA) for truckload/unload boom conflicts, public protection, etc.
    5. Risk Assessment (RA)/Job Hazard Analysis (JHA) for power line encroachment
    6. Logistics Plan (LP)
    7. Weight of Material (WM) – Bill of Lading (BL), calculation, manufacturers product datasheet, etc.
    8. Rigging Plan (RP)
14. The Crane Manufacturing Company must provide with the following information added to the Crane Lift Plan (CLP):
    1. Competent/qualified person designation forms for the operator and Assembly & Disassembly (A&D) Supervisor.
    2. Operator/Worker accreditation – e.g.: license, medical certification, etc.
    3. Load Chart (LD)
    4. Range Chart (RC)
    5. Dimension illustration and specifications for the crane.
    6. Lightning and wind restrictions (from operator’s manual).
    7. Crane dimensions and area (quadrant) of the operation diagram.
    8. Provide a copy of annual 3rd party inspection certification and report – see, Crane Lift Plan for requirements.
    9. The inspector shall be accredited with the CCAA.
    10. Scaled Site Plan (SSP) and Elevation Drawings (ED).
    11. Job Hazard Analysis (JHA) for Assembly/Disassembly of crane and severe weather.
15. The crane activity shall comply with the Site-Specific Safety & Loss Control Program.