Crane safety

Crane safety is one of the most important things to get right on site. As with anything at height, if something goes wrong the consequences can be very grave. Bill Tunney investigates the issues and explains what procedures should be in place to ensure that cranes operate safely.

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By  Colin Foreman Published  November 27, 2004

Crane safety|~||~||~|At the time of the accident at the Dubai airport, when the steel/scaffolding collapsed killing five and injuring 17, there was a strong rumour circulating that the accident happened when a crane hit the top of the steel reinforcement cage, toppling it over onto the helpless workers underneath. Regardless of exactly what happened, anyone can appreciate that it might have happened this way. Cranes working on a building site are an accident waiting to happen. They are a moving part carrying a load at height. Sounds like a description of a plane doesn’t it? And just like the aviation industry, when we use a crane we have to follow rules to keep those accidents at bay. When operating a crane on site it is important that a ‘Lifting Operations’ procedure is in place. This should define methodologies for managing and controlling lifting operations in compliance with country laws and project health, safety and environmental policies. The main objectives of the procedure should include, but not be limited to the following: an outline of the basic requirements in lifting operations, involving the use of cranes and other lifting equipment used on construction sites of the project; the provision of adequate guidelines to eliminate or minimise exposure to risks related to lifting operations, this ensures that lifting is being carried out in such a way that all personnel involved, and others working in the vicinity are not endangered; ensuring that all lifting operations shall be controlled and carried out by qualified and experienced personnel; and ensuring that all lifting operations shall be carried in compliance with the project’s HSE&S plan, the relevant client rules and regulations and local laws. It also is vital that a ‘competent person’ supervises the operation. He must be qualified to ensure the testing, examination and certification of lifting equipment. This means they should have the requisite knowledge to certify whether the lifting equipment is free from patent defects and is suitable in every way for the duty required. Crane operators should only be appointed if they meet certain requirements. First, they must be over 21 years of age, competent, physically and mentally fit, tested and capable of operating the crane safely. Second, they should also have full knowledge of the duties of the riggers and banks-men, with full understanding of signals used by them during lifting operation. An operator should also be: adequately trained and familiar with the crane he is assigned to operate; be able to judge distances, heights and clearances; not be colour blind; know the means of escape and the proper use of fire extinguishers; be authorised and licensed to operate the crane and provide documents to prove he is capable of operating heavy equipment; and responsible for the safe operation of the equipment. This is important because it is the operator that must ensure that all movements are made smoothly and at a safe speed, project speed limits are observed and that no riders are permitted on the machine. The actual lifting operations should be controlled by a trained banks-man or rigger who should be: Trained and experienced; able to determine the weight, centre of gravity and characteristics of a load; inspect and determine whether a wire rope, sling, or other piece of lifting equipment is damaged or not fit for the purpose; familiar with the different and correct slinging techniques; know the correct hand signals, so as to communicate safely and correctly with the operator; and ensure that taglines are used on all loads. All lifting operations should be planned to ensure that they are carried out safely, and that all foreseeable hazards are identified and all risks eliminated. Planning shall basically contain and consider the following; the weight of the load; size of the load; method of lifting; selection of appropriate rigging; the working radius; positions of obstacles; communications system; weather conditions; selection of equipment; and whether the appropriate work permit has been granted. The cranes themselves must be correctly supported and all outriggers and other lifting aids should be deployed before lifting commences. Cranes and other side booms when used shall be positioned so that they lift vertically and are not used to pull loads sideways. Mobile lifting equipment should not be operated when the top of the job or fly-jib is within 3 m of live overhead power cables. No person should be positioned beneath the load, hoist or jib during lifting, and loads shall not be lifted over the heads of personnel. All mobile equipment must have reversing audible reversing alarms. The ground conditions are another important fact when it comes to planning a lift. The outrigger and track loading should be established before sitting the crane, and that should take into account the added weight when lifting operations take place. When sitting a crane in live operational areas and on concrete ground, the safe load limits should be identified against the specification of the area involved. For other areas the density and compaction qualities of the ground should be assessed. All outriggers used must be used as specified by the manufacturer of the crane. Sound timber packing or metal plates should be positioned under each outrigger pad to distribute the load. The outriggers must be extended on both sides when performing a lifting operation, and they must be properly set and locked where locking devices are provided. Ultimately, it is the operator’s responsibility to ensure that the pad of each outrigger is positioned correctly and safely before lifting a load. In reference to lifting operations procedures, all lifting equipment used shall be certified in accordance with relevant local legislation. If the equipment is being brought into use for the first time (manufacturer certification) must be stamped or logged on the equipment. This is also necessary if a crane has undergone any substantial alteration, or repair (as per relevant local legislation and client requirements). Any cranes brought to site should be load tested by a third party authority and have a load radius indicator fitted. Once onsite operators should check their cranes daily, for oil, hydraulic oil, leaks, and water. It is also important that the crane manufacture’s manual is adhered to when any maintenance or repairs are performed. No part of a crane which is subject to lifting stresses shall be altered, welded or changed in any way without reference to the crane manufactures procedures and instructions. Any other slings, shackles, belts and any other piece of lifting equipment, should have a valid certificate. All lifting gear must be colour-coded to confirm inspection and compliance with local and/or company procedures. This indicates to the user and the inspector, that an examination has been performed within the prescribed period. For controlled sites with good supervision and checking of lifting gear a new colour should be introduced every three months and each colour shall be current for a period of three months. For ‘uncontrolled’ sites with poor supervision and checking of lifting gear it is recommended that a new colour be introduced each month. Any lifting gear that does not have a visible colour band, or one that is out of date, should not be used and returned to the rigging store for examination. Painting of the colour codes and the updating of the information boards is the responsibility of the lifting equipment supervisor. To assist operators, all mobile cranes shall have a conspicuously posted sign, stating the length or lengths of the boom, which may be fitted, safe working load capacities at the appropriate radius, and recommended operating conditions. Such instructions plaques should be readily visible to the operator when seated in his control station (cabin). There should also be a sign warning of the danger of overhead power lines. The area surrounding every power line must have an absolute limit of approach defined. It is strictly forbidden to move any crane boom or load line into this area, unless the line has been de-energised or insulated. Once the voltage has been identified, then height-restricting facilities shall be erected around the overhead lines, to indicate the safe working distance. Another hazard that the operator must be aware of is the “wind force’, i.e. side loads, down drafts, etc. as applied to the load and the boom. When wind velocities are above 32 km/h, the rated load and boom lengths shall be reduced according to the manufacture’s specifications. It is important to remember that wind forces are up 35% stronger at height.||**||

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