Lifting Activity

Hazards of Lifting: 

1. Collision with adjacent structures and overhead power lines 
2. High wind (greater than 17 knots/32 km/h)  
3. Working under the suspended load 
4. Failure of load bearing lifting equipment  
5. Failure of support 
6. Overturning  
7. Overloading 
8. Loss of load 

Controls of Lifting: 

1. PTW 
2. TRA, approved method statement  
3. 3rd party certificate and Color coded of Equipment. 
4. Approved Lifting plan 
5. Barricading with signage 
6. Outriggers with baseplate 
7. Sole board 
8. Do not exceed SWL (load chart, color coding, ASLI)  
9. Rigger should be present 
10. Tagline 
11. Wind speed should be monitored 32km/ 17 knots 
12.Proper distance from overhead lines-3m 
13. No unauthorized person allowed under the lifting 
14. Proper height 
15. Proper speed 
16. Supervision 
17. Communication  

Lifting Plan: 

It is a document prepared by lifting supervisor/Crane coordinator and approved by safety department to prepare a critical lift by calculating and considering all the factors which is going to effect the lift.  

Elements of Lifting Plan: 

1. Overview of the area (working area, Environment, nearby objects and overhead live utilities)  
2. Weight of the lift 
3. Dimensions of the lift 
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4. Centre of gravity of the lift 
5. Crane and its capacity, SWL 
6. Lifting tools and equipment 
7. Boom and sling angle 
8. Risk Assessment  
9. Responsible person and involved persons 
10. Good work practices  

Safety Devices in Crane: 

1. ASLI (Automatic safe load indicator) - All jib cranes with a Safe Working Load (SWL) of over one tone shall be fitted, third-party inspection authority (LEICC) shall be permitted to make ASLI adjustments. 

2. Anti-two-blocks devices - It is an electro sensing device to prevent the contact of boom sheave assembly point and hook assembly. 

3. Anemometer - It is mounted high up (top of the boom) on the crane.

4. LMI (Load movement indicator) – Also known as RCL( Rate Capacity Limiter) ,a system which warns the equipment operator by sensing (directly or indirectly) the overturning moment on the equipment, i.e., load multiplied by radius.

5. Limit switches  

6. Out- Riggers - Outriggers provide  a  solid  base  for the crane 

•  If ASLI is activated during the lifting equipment, operator shall stop the lifting activity and return the load to its original place.

•  1 m clearance should be there between lifting appliances and any adjacent fixture 
•  3 m distance from live cables 
•  Boom angle indicator: A device which indicates the crane boom angle. 

Types of Cranes: 

1. Mobile crane 
2. Crawler Crane 
3. Tower Crane 
4. Overhead crane 

Parts of Crane: 

1. Boom 
2. Flying Jib 
3. Main hoist 
4. Auxiliary hoist 
5. Pulley 
6. Lifting gear 
7. Sling 
8. Hooks 
9. Shackle 
10. Out riggers 

11. Anti-two-block device
12. LMI (Load movement indicator)  

Types of booms: 

1. Telescopic 
2. Lattice 
3. Articulating 

Lifting Equipment:

1. Hooks (Hooks open 15% of normal throat are unsafe)  
2. Pulley 
3. Lifting gear 
4. Slings (slings shall be rejected if found 1/3 of original outside diameter eroded or twisted more than 10 degrees from the plane)  
5. Shackles 

Types of Slings: 

1. Wire rope sling 
2. Synthetic/Nylon Slings 
3. Chain Slings 

WLL (working load limit)  

The max load that a lifting equipment is designed to sustain.  

Formula for calculating WLL of slings at specified angle.

WLL=vertical hitch WLL X no. of legs X sling angle factor 

Example: 

WLL of grey nylon sling with 2 legs at an angle of 60° 

WLL=vertical hitch WLL x no. of legs x sling angle factor 

= 4000kg x 2 x 0.866 

=6928 kg 

SWL (Safe working load), RC (Rated Capacity)  

The max allowable safe load that is allowed to lift through a lifting equipment.  

Work Radius: 

The maximum distance where a certain activities of lifting and rigging are in progress.  

Load Chart: 

A systematic & graphic device to indicate the amount of authorized work yet to be performed by the machine. 

•  It shows how much Boom angle and radius is required to lift the load.  

PWASS (Proximately Warning Alarm System) 

It is installed in heavy equipment like excavator, bull dozer etc. This system automatically give alarm when anybody come in touch within 5 meter radius of equipment. 

Types of lifting: 

1. Normal lifting  ( Load less than 20 tons)  
2. Heavy lifting (load greater than 20 tons)  
3. Critical lifting (tandem lifting-use 2 cranes, load greater than 75% of SWL, over the Existing live utilities)  

Where tandem lifts are used? EXAMPLES 

• Long components where movement of lift from horizontal to vertical is needed.  
• To lift structural beams for bridges 

Sling hitches used during lifting and their effect on Working Load Limit 

Mainly three types of sling hitches are used to attach load to the crane hook. 

1. Vertical hitch 
2. Choker hitch 
3. Basket hitch                  

Effect of sling hitches on WLL 

• Vertical hitch- When a sling is used in a vertical hitch, full lifting capacity of the sling is utilized. 

• Choker hitch - In case of choker hitch, 25% of the capacity is decreased due to stress created at the choke point. 

• Basket hitch (90°) - The capacity of the sling in this hitch is twice that of the same sling in a vertical sling because two ends (legs) of the sling function as they were two separate slings. It requires two hooks or a spreader to attach both end of the sling. 

• Basket hitch (less than 90°) - When slings or sling legs are used at an angle during a lift, the sling capacity is reduced. Lesser the angle, lesser the capacity. There are Sling Angle Factor that is used to calculate the capacity 

Pre-engineered lift 

A pre-engineered lift is a repetitive or routine lift performed for assembly or disassembly of components or systems in which the item to be lifted are identical in terms of dimensions, weight, center of gravity, load path, attachment to the lifting equipment and selection of the lifting equipment. In this type of lift all items can be lifted in adherence to a specific routine step-by-step procedure that eliminates rigging decisions or calculations. 

Rigger: 

• Rigger I – Required for lifts over 40 tons 
• Rigger II – Can’t Rif a load over 40 tons 
• Rigger III – Can’t Rif a load over 10 tons 

Responsibilities of Rigger: 

1. Inspection of lifting Equipment and filling daily checklist 
2. Safe use of lifting equipment  
3. Safe storage of lifting equipment  
4. Barrication of work radius 
5. Attaching and detaching of load with lifting equipment  
6. Put Tagline 
7. Communication with the operator 
8. Aware of the Hazards of lifting 
9. Proper positioning of load 
10. Inform supervisor in case of any contingency.