New trains of thought on lifting01 December 2006
Every so often lifting equipment fails, generating the kind of headlines that no one wants to see. These unfortunate incidents occur despite safety checks carried out by the manufacturer and further regular checks undertaken by the end user, in accordance with the respective regulations. However, a high proportion of accidents can be prevented, if the operator pays more care and attention. For this reason, issues such as load stability and operator positioning are becoming hot topics in the world of cranes, lift trucks, hoists and mobile elevating work platforms.
Regulations such as the Lifting Operations and Lifting Equipment Regulations 1998 are clear and state that lifting equipment provided for use at work should be:
- Strong and stable enough for the intended use and marked to indicate safe working loads
- Positioned and installed to minimise any risks
- Used safely - ie, work is planned, organised and performed by competent people
- Subject to ongoing thorough examination and, where appropriate, inspected by competent people.
The Provision and Use of Work Equipment Regulations (PUWER) 1992 is a broader set of regulations, with responsibilities for purchasers and operators. Any person or company that buys equipment must ensure it is suitable for its intended use. They must also make sure it is properly maintained, regularly inspected and that the information is logged. PUWER also determines any specific risks, and details what information and instructions must be made available to operators.
Street Crane has more than 60 years' experience in crane design and is firmly established as one of the world's leading volume overhead crane and hoist manufacturers, yet the company concedes that crane safety is a complex issue.
Street Crane says there are many factors that need to be taken into account in designing a crane to promote safe use. One is operator location. Here, high-level cabs are the traditional solution, placing the operator away from the working area and providing good overall visibility. Where cranes are in continuous use, these may be ideal, but factors such at the presence of fumes or high temperatures have to be considered. Where such hazards are present, provision needs to be made to pressurise or air-condition cabs to ensure operator safety and efficiency.
In many situations, crane operators are required to perform other tasks, such as loading and unloading. This often demands crane operation from ground level. Usually a control box connected to the crane bridge by a heavy-duty umbilical allows the operator to control lift, travel and placement.
According to Street Crane, a variation on this theme is the use of remote radio control. By eliminating the umbilical, this allows operators greater flexibility in location, so they can choose a position that gives the best view of operations and greatest safety.
Another factor to consider is special handling devices. For many applications, a traditional hook, allied to the use of a chain or sling, provides the ability to manage many kinds of loads efficiently. However, it is important to invest in training, so the operator can attach loads safely. In addition to promoting stability, a correctly attached load will impose less strain on the hoist and crane, and promote longer crane life. Street Crane insists that traditional hook-and-chain arrangements are inappropriate for many loads. The crane industry has therefore developed a range of special handling devices to suit specific applications. For instance, vacuum devices are used for sheet material, such as glass and steel. Devices have even been developed for the glass industry for safe transportation of multiple sheet packs. Similarly, in metals handling, special grabs are common for coil handling.
Aside from promoting safety, these dedicated handling devices often contribute to productivity improvement by allowing quicker loading and unloading, so crane cycle times are reduced.
Yet another hazard attributable to operator awareness is collision. It is quite common in large factories for two or more cranes to operate in the same bay. This poses a potential hazard and Street Crane frequently installs anti-collision systems that prevent cranes working within the same zone.
Where Goliath or semi-Goliath cranes are in use, there is a potential hazard from an approaching crane. Sounding devices and hazard lights are therefore fitted to signal the approach in good time. These systems are equally applicable to internal and yard cranes. For external cranes, it is also common to install floodlights for safer autumn and winter afternoon and night-time working.
Crane and lifting equipment manufacturers and suppliers are required to be ever more vigilant in the light of highly publicised fatal accidents. Working towards its safety ambitions, Speedy Lifting has achieved full membership of the Lifting Equipment Engineers Association (LEEA), becoming its biggest single full member. Full member status has been awarded is in recognition of the company's commitment to delivering high technical and safety standards within industry. The business passed a detailed LEEA audit, which requires full members to conform to stringent standards for equipment, personnel, procedures and records.
Exemplifying its commitment to safety, Speedy Lifting has recently supplied an innovative health and safety system as part of United Utilities' £2.6 billion programme of water treatment infrastructure works in the northwest region. The company specified a bespoke man-riding davit rig to provide emergency lifting for contractors draining and cleaning 12m deep water holding tanks at United Utilities' Wybersley treatment works in Stockport.
Speedy supplied the davit rig in consultation with equipment suppliers UCL after an on-site health and safety assessment highlighted the need for a fail-safe rescue system to lift contractors out of the water tanks in an emergency. It is the first system of its kind supplied by Speedy Lifting and will be on site for the 10-week duration of the project.
In terms of saving lives, making lifting equipment 'fail safe' is the preferred method of negating reliance on the operator to perform tasks in a correct and responsible manner.
The rail industry is another sector where this policy is paying dividends, as highlighted by Pfaff-silberblau, which has been selected by Metronet Rail to supply 34 of its type HD 10 tonne swl screw jacks to the London Underground maintenance depot at Northumberland Park. This follows on from an order for eight similar screw jacks at London Underground's West Ruislip depot last year.
The new Pfaff systems are to be installed as an integral element of Metronet Rail's ongoing preventive maintenance programme. Each system comprises eight screw jacks, synchronised by a central control panel. The screw jack systems lift complete train car bodies to facilitate the changing of bogies. Their use accelerates the process, ensuring that rolling stock can be returned to service in minimum time.
Many safety features are incorporated into the screw jacks, including wear monitoring nuts, which also act as fail-safe devices in the unlikely event of failure of the main load-bearing nuts. The quest to improve safety is continuous. A key factor is ensuring the crane or lift is fit for purpose and closely matched to operational needs. This requires careful consideration of the process and how the equipment will be used. Crane or lift structures and mechanisms that suit the duty cycle can then be selected, with the appropriate controls and handling devices.
The hidden obligations behind Duty of Care
In law, the Duty of Care regulation (part of the Health & Safety at Work Act) states that it is "the legal requirement that a person exercise a reasonable standard of care to prevent injury to others". Yet what happens when someone is performing the routine examination and inspection of lifting equipment where components are not visible, unless dismantled?
It's a grey area that has been highlighted by the tragic death of Sam Ball, a 23-year-old construction worker, who was struck by a concrete beam that fell from a mobile crane in Hertfordshire in January 2002. The Health and Safety Executive has published a report (www.hse.gov.uk/construction/fatalinjreport.pdf) on its investigation into the accident. Forensics established that a pin forming part of the lifting tackle had fractured in two places and become dislodged, causing one end of the lifting frame to drop.
According to Dave Rothery, head of operations (London, east and southeast) at HSE's construction division, "the investigation findings raise a wider issue for consideration by those undertaking routine examination of lifting tackle and HSE is publishing this report with a view to raising awareness of the circumstances leading to Sam Ball's death and, in particular, the implications.
"We advise that, where lifting tackle components are not visible, the competent person undertaking the examination should give careful consideration to the circumstances in which such components should be removed for examination or routinely replaced. Lifting equipment manufacturers and suppliers should provide information on this subject to their customers."
Lifting equipment includes any equipment used for lifting or lowering loads, including attachments used for anchoring, fixing or supporting purposes.
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