Dangerous Occurrence: Collapse of mobile crane

Transcription

1 Accident Case Studies Dangerous Occurrence: Collapse of mobile crane Crane Operator had hoisted up a bag of sand (780 Kg) over the rooftop. While doing so, the Overload Radius Indicator (ORI) alarm sounded and the cut-off was activated by Operator. However, he by-passed the cut-off and continued to lower the boom of the crane, based on his years of experience. The crane suddenly toppled when he started to swing the boom to its left. 1

2 Factors Contributing To Collapse Site constraints. No lifting plan. No risk assessment conducted. No Permit-To-Work system Implemented. Outriggers not fully extended. By-passed of safety devices. Operator at-risk behaviours. Safe Working Load exceeded. Lifting Supervisor, Rigger and Signalman were not appointed & not present on-site. How to prevent the accident? It is important: personnel involved in the lifting operations are aware of the factors and know what to focus. 2

3 Factors Affecting Safe Lifting Operation Machine? Medium? Material? Method? Man? Factors Affecting Safe Lifting Operation Many factors affect the lifting operation. Broadly, they can be classified into the followings: Machine lifting equipment for the job as well as the integrity of the lifting equipment to perform the job; Material the load that is intended to be lifted; Medium the environment in which the lifting operation is to be carried out; Man the competency, roles and responsibilities of personnel involved in the lifting operations; and Method the planning and procedures to be adopted for the lifting operation i.e. lifting plan. 3

4 Cause & Effect Analysis Diagram USES OF CAUSE & EFFECT DIAGRAM To study all possible reasons for a process that is not producing the desired results To study all possible causes to a problem To identify areas for data collection for more in-depth analysis of the problem To determine the root cause(s) of a problem Cause & Effect Analysis MAN METHOD MEDIUM Take no Responsibility Human error Poor Communication Lack of supervision Inadequate Knowledge No Risk Assessment No lifting plan No safe work procedure Inclement weather Poor ground condition Site Constraints Effect: Collapse of Crane Load weight not ascertain Misuse Inadequate servicing MATERIAL No rigging point MACHINE Outriggers not fully extended To study all possible causes and identify areas for data collection for more in-depth analysis of the problem 4

5 Cause & Effect Analysis MAN METHOD MEDIUM Take no Responsibility Human error Poor Communication Lack of supervision Inadequate Knowledge No Risk Assessment No lifting plan No safe work procedure Inclement weather Poor ground condition Site Constraints Effect: Collapse of Crane Load weight not ascertain Misuse Inadequate servicing MATERIAL No rigging point MACHINE Outriggers not fully extended To determine the root causes of a problem Development of Solution - Lifting Plan Lifting Plan A lifting plan should not limited to, address the followings: 5

6 Site Preparation Site Review & Set-up Job-site conditions: Supporting surfaces Access & stability (transportation) Outriggers Levelling of ground Working area Competency of Personnel: WSH (Operation of Cranes) Regulation The personnel required Crane Management Team 6

7 The personnel s roles, responsibilities and competencies Permit-To-Work system Permit-To-Work System Procedure Supervisor of the Work (BCSS Trained) Safety Assessors WSHO / WSHC Project Manager Supervisor of the Work Yes Yes Supervisor to ensure Project Manager to Close And file in record Yes Yes Application Assessed Duties of Occupier to ensure PTW system are carried out. Approved Posting / Supervisor s Duty Close No No No No Pose a risk to Safety Re-Apply Any person to report any incompatible of works being carried out. Revocation 7

8 Risk Assessment A Risk Assessment is a systematic method of looking at work activities, considering what could go wrong, and deciding on suitable control measures to prevent loss, damage or injury in the workplace. The Risk Assessment should include the controls required to eliminate first. If not, reduce or minimize the risks. Nature and weight of load Some loads can be more difficult to handle because of what they are or how they are being packaged. When handling a load, consider its weight, bulk shape, stability and predictability. 8

9 Type and location of lifting points Using the suitable lifting gear to engage to the correct lifting point to ensure NO failure in the lifting operation. Selection of appropriate lifting gears and equipment Ensure the lifting gears selected are able to keep load secured, balance and with adequate SWL for the load. 9

10 Assessment of the need for tagline to control movement of suspended load It is a good practice to use tag line to control any load from swaying and to keep a safe distance from hoisted load to prevent load injuring the rigger Means of communication during lifting operations Lifting team shall practice the standardize communication in all lifting operations. 10

11 Factors detrimental to the lifting operations such as: inclement weather and poor illumination Prohibition to operate the crane under strong winds condition that affects safe operation; during inclement weather; or when there is insufficient lighting. Provision of a safe place of work for all personnel during lifting operations Suspended Loads The operator of any crane shall as far as is reasonably practicable not to move a suspended load over the head of any person. No one is allowed to work under suspended load at anytime. 11

12 Safe work procedure Safe work procedures are a series of specific steps that guide a worker through a job task from start to finish in a chronological order. Safe work procedures are designed to reduce the risk by minimizing potential hazard exposure. Others Essential knowledge Lifting & Rigging Safety Awareness 12

13 Collapse of crane - Most of the cranes collapsed over-the-side Most of the crane toppled over-the-side Safety awareness for crane operation The load carrying capacity of the crane varies according to the various quadrants Over the side Over the front Operating Zones called quadrants The operation zone Quadrant of operation Over the rear Over the side 13

14 Safety awareness for crane operation Most of the crane collapse over-the-side The capacity of the crane may change when rotating a load from one quadrant to another. The Stability of crane over-the-side is always weak as compare to over-the-front or over-the-rear Safety awareness for crane operation To obtain a safe quadrant is the first consideration for crane set-up operations Instead of the convenience of parking the crane or other convenient reasons 14

15 400t hk hard core Ensure safe operation Adopt to the basic principles of crane operation: Stability of Crane (Tipping Stability) Structural Stability Integrity of Lifting Gear / Safety Devices Ensure safe operation Stability of Crane (Tipping Stability) - Obtain a safe quadrant - Ensure crane operate on good footing - Outriggers fully extended - Crane rest on level & firm ground 65 ton 25mm thk steel plate (2.4mx4m) outrigger base plate 25mm thk steel plate (6mx3m) 45 compacted subgrade 45 15

16 Ensure safe operation Structural Stability - Do not overload crane (refer to load chart always) - Ascertain the load weight before any lift. Ensure safe operation Integrity of Lifting Gear / Safety Devices - Wire ropes / Rigging equipment are in good working conditions - e.g. Over-hoist / over-load limit switch in good working order 16

17 Have a successful lift! To conclude: Plan to lift & NOT lifting then plan! 17