Cranes Safety

cranes

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General Safety Requirements:

·        Employers must permit only thoroughly trained and competent workers to operate cranes.

·        Operators should know what they are lifting and what it weighs, for example, the rated capacity of mobile cranes varies with the length of the boom, the boom height, the boom angle and the boom radius.

·        To reduce the severity of an injury, the employer must take the following precautions:

1.     Equip all cranes that have adjustable booms with boom angle indicators.

2.     Provide cranes with telescopic booms with some means to determine boom length.

3.     Post load rating charts in the cab of cab-operated cranes.

4.     Require workers to always check the crane’s load chart to ensure that the crane will not be overloaded by operating conditions.

5.     Instruct workers to plan lifts before starting them to ensure that they are safe.

6.     Tell workers to take additional precautions and exercise extra care when operating around power lines.

7.     Teach workers that outriggers on mobile cranes must rest on firm ground, on timbers, or be sufficiently cribbed to spread the weight of the crane and the load over a large enough area.

8.     Direct workers to always keep hoisting chains and ropes free of kinks or twists and never wrapped around a load.

9.     Train workers to attach loads to the load hook by slings, fixtures, and other devices that have the capacity to support the load on the hook.

10.      Instruct workers to pad sharp edges of loads to prevent cutting slings.

11.     Teach workers to maintain proper sling angles so that sling are not loaded in excess of their capacity.

12.    Ensure that all cranes are inspected frequently by persons thoroughly familiar with the crane, the methods of inspecting the crane, and what can make the crane unserviceable.

13.       Ensure that the critical parts of a crane – such as crane operating mechanism, hooks, air, or hydraulic system components and other load-carrying components – are inspected daily for any maladjustment, deterioration, leakage, deformation, or other damage. 

CRANE SAFETY

Planning Before Start-Up

Level the crane and ensure support surface is firm and able to support the load

Contact power line owners and determine precautions. Know the location and voltage of overhead power lines. 

Know the basic crane capacities, limitations, and job site restrictions, such as the location of power lines, unstable soil, or high winds. 

Make other personnel aware of hoisting activities.

Barricade areas within swing radius.

Ensure proper maintenance and inspections.

Determine safe areas  to store materials and place machinery.

CRANE SAFETY

Only people that have trained are permitted to operate cranes

CRANE SAFETY

Barricades around the swing area of a revolving cab must be used when operating  a crane in areas where pedestrians or traffic pass close by.

CRANE SAFETY

Never operate cranes closer than 10 feet from power lines. Voltages greater than 50,000 volt require greater distance.

CRANE SAFETY

Before lifting carefully inspect all rigging, slings, hooks, etc.

Report any damage or defects to your supervisor right away.

CRANE SAFETY

When it is necessary to guide a suspended, use tag lines.

CRANE SAFETY

Don’t distract the crane operator. Only one signalman at a time.

CRANE SAFETY

Never ride the load, ball or hook.

CRANE SAFETY

Keep out from under suspended loads.

Watch out for materials that could fall on you if hit by the moving load.

CRANE SAFETY

Make sure you provide yourself a way out when directing load drops.

TOWER CRANES

Types of Tower Cranes

Rail Mounted, supported on a carriage running on a parallel set of rails.

Outrigger Mounted

On a fixed base, supported on a concrete base.

Climbing type, supported by floors during the construction of a multi-stored building.

On crawler tracks.

Slewing Tower & Non-Slewing Tower

Slewing: the slewing ring is situated at the bottom of the tower and the whole of the tower and jib assembly slews relative to the base of the crane.

Non-Slewing: The slewing ring is situated at or near the top of the tower and the jib slews about the vertical axis of the tower which itself remains stationary.

(should be tied to the to a fixed structure.)

Types of Jib

Horizontal Trolley Jib

Inclined trolley Jib

Luffing Jib

Fixed Radius Jib

Safety Measures - Site

Away from high voltage power lines.

Away from excavation sites.

Prevailing Wind-speeds.

Away from water accumulation – water leaking under the foundation of the crane.

Overlapping levels with other cranes. To avoid collision some one (competent person) should plan the sequence of crane movements.

Safety Measures - PPE

Safety Harness

Helmets

Safety Shoes

Fire Extinguishers

Easily Accessible

Trained 

Crane Safety Equipment

Automatic Safe Load Indicator

Load Radius Indicator

Motion Limiting Devices

Overload Cut-out devices

Level Indicator

Anemometer

Machinery Guarding

Zoning Devices (two or more cranes – limit the slew, the trolley motion, or the travel motion

Crane Safety

Lighting Protection (Earthing)

Rail mounted tower cranes should be fitted with an audible travel alarm.

Ladders – Landing (Platform)

Access to and along jibs and counter jibs for inspection and servicing should be made safe. (catwalks should be provided with handrails)

Clear vision from cab

Tower Cranes

Visual Examination

Overload Test (swl raised to sufficient height to ensure that each tooth of the train of gears is subjected to the load then lowered to 100 mm to 200 mm above the ground.

SWL should then be increased by 25 % and this load hoisted sufficiently to ensure that each tooth of the train of gears is subjected to the overload then lowered to 100 mm to 200 mm just clear of the ground.

For horizontal jib cranes with trolleys the trolley should be set at the maximum radius for swl.

Swl (100 mm to 200 mm) – 25 % of swl (100 mm to 200 mm)

Continued

Indicator test: 

The crane should never loaded beyond 100 % of its swl.

The radius at which the test load corresponds to 110 % of the swl should be marked and the test load should never be taken beyond this point.