How to plan a lift16 August 2006
Without sufficient planning and supervision, crane accidents can happen. If something goes wrong, the consequences are likely to be disastrous - severe damage to property with risk of injury or loss of life is a real possibility. Good planning protects cranes and the people working around them, explains Ian Fisher, director of Ainscough Training Services, a sister company of the UK’s largest crane hire company
Cranes are today some of the most versatile pieces of equipment to be found working on many industrial and construction sites. When used correctly on firm level ground, and with a fully trained and competent lifting team, mobile cranes are also one of the safest items of equipment.
All lifting operations in the UK must comply with the Lifting Operations and Lifting Equipment Regulations (LOLER) 98. These regulations place a legal duty on any employing organisation to properly plan and appropriately supervise each and every lifting operation. Thankfully, the British Standards Institution provides a very useful code of practice called BS7121 to help employers to understand and comply with LOLER when using mobile cranes.
When broken down into stages, the planning of a safe lifting operation, no matter how complex, can be relatively straightforward.
Know your limitations
Once the need to move a load using a mobile crane has been established, the employing organisation needs to determine if they have the necessary competent staff in-house to plan a safe system of work for the lift. If so, it can opt for the crane hire contract conditions from the UK’s Construction Plant-hire Association (CPA). Although this is the cheapest option, the employing organisation assumes full responsibility for safety throughout the lifting process, including all planning and supervision.
In the UK, there is another option for contractors which are unsure if they have sufficiently competent staff in-house. Under the terms of the CPA’s contract lift conditions, the crane hire company prepares a safe system of work, provides all the equipment and accessories and carries out the lift with trained and competent operators.
In both cases, crane hire and contract lift, a single person will be appointed to take full control and total responsibility for the planned lifting operation.
The term ‘appointed person’ is introduced by BS7121. An appointed person is competent, with sufficient training, technical knowledge and experience, to develop a safe system of work for lifting operations, in order to satisfy the needs of the employing organisation.
The appointed person (AP) will start by gathering essential information which is likely to require liaison with other companies, organisations and personnel. The AP will need to visit the location of the planned lift site to gain all the information that is needed and therefore have a complete understanding of what is required.
On his first visit to site the AP will be looking for access and egress points for both the crane and load transport. The condition of ground the crane will travel across and, most importantly, where it will be rigged will form part of the crane selection and crane support criteria. Existing proximity hazards and any ongoing construction work which may develop during the lift planning phase will be of particular interest to the AP.
Once a rough sketch of the area has been made and some detailed notes taken, the AP can start considering the other aspects of the lifting operation.
Full and detailed written information regarding the load or loads must be obtained. This information will include such items as:
•Description. What type of load is it - vessel, container or a motor?
•Weight. Are the net and gross load weights known, making suitable allowances for factors of safety, and such additional items as crane hook blocks, boom extensions and the weight of accessories?
•Size. What are the load’s dimensions, its centre of gravity, and its location before, during and after lifting?
•Lifting points. What are the suitability, integrity and location of lifting points? A slinger or others will need to gain access to the lifting points of the load safely, to attach and remove the lifting accessories.
•Contents. Are there any hidden contents that could affect load weight and stability, or which could be hazardous if spilled?
The AP should also write down information about the location, to include:
•Nearby collision hazards. Is the area where the crane is to be sited suitable? Could there be tower cranes working above the standing position of a mobile crane, or a crane sited next to a haul road? Can fly jibs, if necessary, be rigged safely without problems arising from obstructions? Can the crane’s superstructure rotate through 360 degrees without causing a trapping point between the counterweight and a fixed object? Will the setting of crane outriggers be done in accordance with manufacturer’s instructions?
•Ground conditions. Is the ground where the crane is to be sited firm and level? Is it capable of withstanding the high outrigger jack loadings that are going to be applied to it? It is the duty of the AP to know the ground’s bearing capacity. Information on ground conditions can be obtained from the site and information on outrigger loadings can be obtained from crane suppliers and manufacturers.
After considering the load and the location, the AP should choose a crane. For example, if the crane is needed for the long term and the ground conditions are too soft for wheeled mobile cranes, the AP may opt for a crawler crane.
The appointed person needs to know cranes well. In particular:
•The capabilities and limitations
of each crane type
•The methods of work the crane
•The cranes’ “duties”, that is, their
safe working loads,
•The dimensions and weight of the crane, in road travel and set up for work
•Calculated outrigger loadings.
The AP should also know if there are any restrictions and limitations to the crane’s use, or if the crane needs to be fitted with additional safety devices such as engine overspeed shut down valves, spark arrestors, slewing restrictor or
The relationship between an appointed person and a crane supplier is vitally important. The crane supplier has a duty to provide a crane that is well maintained, certificated and fit for purpose, and the appointed person has
a duty to ensure that that is the case by undertaking a visual inspection of the crane and its statutory documentation. Cranes are becoming more and more complex and technologically sophisticated. Some information regarding the crane’s use can only be provided by the supplier. The choice of a reputable crane supplier who can advise and guide is the key to obtaining the right product that the AP requires.
Commonly-used accessories include wire rope slings, single chain slings, bow and D-shackles, man made fibre flat belt and round endless slings, eye bolts and multiple leg slings. Choosing the right accessory is just as important as site visit, load calculations and crane choice. Accessories must be fit for purpose and free from common easily identifiable faults and defects. The appointed person is responsible for the choice of lifting accessories that are most suitable for the lifting operation. This decision may depend on including and consulting with others, and relying on the manufacturers’ instructions and guidance. When choosing lifting accessories, the AP must pay particular attention to:
•The safe working loads or working load limits of the accessories required;
•The number and type of accessories needed;
•The number of legs required
•The suitability and compatibility of accessories to each other and to lifting points;
•Most importantly, the calculation of angles between sling and accessory legs.
Lifting accessory manufacturers provide the user with a large amount of technical information on their proper use. Much of this is designed with the user in mind and simplified to ensure the user has a full understanding of their safe and efficient use.
Legal requirements for lifting accessories may differ from one country to another, but generally what is required for all lifting accessories is a means to identify the item, a marking to denote what it is safe to lift, with any additional information on its use such as ranges of angles and reduced loads if applicable, as well as a statutory certification of test and thorough examination.
APs also need to give any accessory they choose a visual inspection prior to use. This inspection will identify the most common faults that may occur during use. These include:
•Cuts and tears
•Stretching, distortion and elongation of links and components
•Hard and soft areas on man-made slings
•Rust and corrosion
•Missing items such as safety catches and pins
•Missing markings such as identity numbers and working load limit markings.
The appointed person may in certain circumstances delegate duties to an equally-competent crane supervisor. The crane supervisor’s role is similar to the AP’s but is more hands-on: implementing the AP’s instructions rather than creating it. One of the crane supervisor’s most important roles is to simply stop the lift if:
•He or she does not understand what is required;
•Unplanned changes to the lifting operation have occurred;
•There are doubts about the continued safety of the lift, or of staff involved;
Assisting the AP and crane supervisor will be crane operators and slinger signallers, responsible for the attachment and removal of lifting accessories. The basic criterion for working in the industry in the UK is that all involved must be competent. To assist in this, there exists a nationally recognised certification scheme the Construction Plant Competency Scheme. There are other certification schemes but the emphasis is on the appointed person to ensure the competency of all involved. All personnel concerned with the lifting operation must be able to work together as a team. Each is equally responsible for the safety and well being of the other teammates. The key to this team involvement is the appointed person, who must bring together information and people from several areas to ensure that the lift is planned properly, supervised appropriately and carried out safely.