|Safe Completion of Crane Recovery at Ardmore II Worksite|
|Sunday, 26 April 2009 11:40|
One of the two large mobile cranes used in the recovery process has been removed and Anderson Road, which had been cordoned off for the recovery operation, is now re-opened to traffic. A second crane parked along Ardmore Park Drive is being dismantled and the road is expected to re-open to traffic on 27 April morning.
Detailed planning to ensure safe recovery of crane To work out the crane recovery plan, a high degree of planning and careful risk assessment were carried out by a team of experts from all the stakeholders,1 including MOM and a Professional Engineer engaged by the main contractor.2 A thorough risk assessment was also made for each work task so that all possible hazards were mitigated before work started.
Concurrently, two key steps were carried out under the supervision of the Professional Engineer. First, the loose parts of the crane were secured to its main mast using chains and chain blocks. Second, two mobile cranes were deployed to Anderson Road and Ardmore Park Drive from the evening of 23 April for the recovery operation. Special care was taken to ensure that these cranes were safely and securely stabilised on the ground for the recovery. It took at least five hours to assemble each crane.
Overview of crane recovery process All parties involved in the recovery were briefed by the main contractor on their roles before recovering the crane in 13 parts using the two large mobile cranes. The first was an 800-tonne crane equipped with a man cage to lift workers and gas cutting tools to the section of the crane to be removed. These workers helped to rig the sections of the crane to be removed to the second crane (700-tonne) before proceeding to cut these sections one-by-one. Subsequently, each section was secured using wire rope slings and then lifted out of the worksite. Please see Annex A for a photo of the crane and its various sections.
Safe recovery operation paramount Highlighting the importance of ensuring a safe recovery operation, Mr Chan Yew Kwong, Deputy Director of the Ministry of Manpower's Occupational Safety and Health Specialists Department, said, “Throughout the crane recovery operation, safety was paramount – of those involved as well as residents in the vicinity. As the collapsed section of the crane was located 140m above ground, any drop may also result in extensive property damage. It was imperative to take all safety precautions to prevent any part from coming loose before and during the operation. Any such movement during the removal could also put the workers involved in the recovery at risk. Hence, the planning for the recovery was rigorous and thorough, which needed more time. In addition, the loads were guided using tag lines to prevent them from swinging. The Ministry is heartened to note that, thanks to the thorough planning and close collaboration among the stakeholders, the recovery operation was conducted smoothly and safely.”
Advisory note for industry Meanwhile, MOM is still investigating the crane incident. A possible contributing factor is the Sumatran squall on the night of 22 April 09 which resulted in strong winds across Singapore. Though this incident involving the ‘flipback' of the boom of a tower crane not in operation is unusual and there are no such incidents in MOM's records, MOM will like to take the opportunity to remind all industry stakeholders using cranes to ensure that they adhere to all safety processes required when using cranes. This includes regular maintenance, annual checks by an Authorised Examiner, daily pre-operation checks before work and ensuring that only trained personnel are engaged in using the cranes. The Ministry will take action against anyone who is found to have violated the requirements under the Workplace Safety and Health Act and its subsidiary regulations. Those who do so face a fine of up to $500,000 and/or two years' imprisonment. 1This included representatives from the main contractor, the mobile crane supplier, the manufacturer of the tower crane Potain, the owner and supplier of the crane, the site developer and MOM. 2The main contractor engaged the Professional Engineer to be the consultant for the entire operation. The PE is also registered with MOM as an Approved Examiner to examine lifting