Materials handling in metal manufacturing
Materials handling is one of the major causes of work-related injuries and death in the metal industries in Western Australia.
Steel comes in many forms including flat plate, coil, round bar, pipes and numerous other profiles each with its own unique problems relating to handling, storage and transportation. Problems may be compounded during fabrication work due to the centre of gravity changing as components are extended or added to the construction piece.
The attachments used to lift steel, such as chains, clamps and hooks are often made from the same material. A licensed dogger is required to undertake the inspection, selection, maintenance and correct fitting of the lifting attachments because the material being lifted can slip or the equipment fail, causing serious injury or death to persons in the vicinity.
Any lifting using a 'slinging technique' for the purposes of lifting a load, including selecting the method of lifting (by consideration of the nature of the load, its mass and its centre of gravity) and inspecting lifting gear (for suitability and condition) requires that the person must hold a high risk work licence for dogging work. Riggers and crane drivers may also have the necessary skills but cannot direct or undertake the slinging of loads at the same time, as they are required to operate the lifting equipment or conduct other duties.
Employees using any type of lifting equipment must also be competent in its use regardless of whether or not a licensed operator is necessary to complete the task.
Plant and equipment for lifting and loading steel product must be suitable for the job.
Cranes and forklifts must have the lifting capacity to operate safely. The safe workloads must be displayed and load charts provided where applicable. High Risk Work Licenses are also required to operate certain types of lifting equipment.
Special lifting attachments, spreader bars, chains, and slings hooks etc must be rated with the safe working load. Plate or dog clamps must be used in an appropriate manner, ie the clamp must only be used to lift one piece of steel at a time.
Caution must be exercised when using chain shorteners. If a claw type shortener is fitted in an inappropriate manner the secured link can twist out of the claw if sideways pressure is applied and allow the load to fall to the ground.
Crane hooks must be fitted with a safety latch.
Caution must be exercised when using web slings to ensure they are not damaged on sharp edges.
The use of a safety glut (glut with a handle) will allow the safe placement and retrieval of the glut from under stacked material.
When lifting it is imperative that the crane is located directly over the load to prevent a pendulum effect when the load is lifted clear of the floor or supporting structure.
The storing of steel poses numerous potential problems that may easily lead to injury if appropriate provision is not made. Hazards include the potential for steel in its various forms to roll, slip, slide or fall over if not suitably restrained. Additional hazards are posed if racking or other equipment provided for storage is unsuitable for the weights involved.
Shelving and racking systems for the safe storage of steel should be engineer designed to meet all relevant standards and be secured to the floor or other fixtures.
Open racking systems should be cross - braced to prevent collapse.
Bollards should be provided to prevent damage by forklifts to corners of racks.
The safe load for any racking system should be clearly displayed in a prominent position.
Heavy items should be stored on the lower racks.
Loading of any cantilever racking should be equal from both sides.
Fixtures must be maintained in good working order.
If a pack of material has to be split the remaining material can be safely restrained by the use of "U" shaped metal gluts.
Flat steel may be stored upright on its end in a specially constructed rack. Appropriate means of access may be required to the top of stored product for the attachment of plate clamps in a safe manner where this type of system is employed. It is good work practice to offset the plates in such a rack to help facilitate the attachment of plate clamps especially when steel plates may need to be physically barred apart to allow access to those stacked on the inner.
Solid steel bar, large diameter pipes and coiled steel pose a greater problem due to their potential to roll if disturbed. Steel in these forms can be safely stored on cantilever racks with a slight incline providing they are not double stacked. The rack arms should be angled up to prevent the product rolling off, or stops provided to restrain movement. Heavy products should be stored at lower levels to ensure stability.
Large steel pipes can be safely stored lying flat and chocked with suitable hardwood wedges or alternatively, secured in specially designed pipe cradles. Large steel pipes should always be transported in specially designed cradles. The scalloped design also allows the pipes to be stacked in a pyramid type arrangement that provides stability during loading and transportation.
Steel coil is one of the most versatile of all raw metal products and is available in coils weighing up to 15 tonnes. It can be rolled, cut into flat sheets and pressed into various profiles to form metal cladding for building, roofs or fences. It can be cut to any required width or length and may be formed into lightweight beams, gutters etc. There is the potential however for violent movement if the coils are disturbed or allowed to unravel.
To illustrate the point consider the average person trying to push a four tonne truck across a flat surface, an almost impossible task. However, the same person could easily roll a four tonne coil with minimal effort. It is therefore easy to see how serious accidents and fatalities can occur when working with coil steel.
Coil steel is traditionally stacked in rows, which can be up to 5 coils high. When this method is used great care must be taken to ensure the end stops have been designed and constructed to restrain any movement. It may also be necessary for every second coil to be chocked with a hardwood wedge.
The largest coils should be located on the bottom row (never rested on top of small coils, which is a recipe for disaster due to heavy weight of the large coil pushing the smaller coils apart). Separate stacks should be kept for different width coils.
A "C" shaped lifting attachment fitted to an overhead crane is usually employed to place and retrieve coils. Coil steel can also be stored and transported standing upright on wooden pallets.
The safest method of lifting and moving steel coils is to use a cradle designed to support the coil at two points on its outside circumference for maximum stability.
The outside arms of such a cradle may also be designed to facilitate forklift tines for safe and easy lifting. The underside of the cradle may also be treated with a non-slip coating to prevent movement.
Problems may be exacerbated where steel coils have been treated with a thin film of oil to prevent surface corrosion.
Steel is still traditionally transported on flat top trucks and semi trailers. In the interest of safety such trucks should be provided with headboards to protect the drivers cab in the event of the load moving forward. Tailgates should prevent the rearward movement of the load and protect other road users from being struck by dislodged material. Steel stanchion pins located in the combing rail will prevent side movement of the load and suitable chains and shorteners should be used to secure the load.
Trucks should be provided with steps and grab rail to allow access to the tray. The provision of a catwalk with a grab rail between the headboard and the cab will enable the driver to supervise the loading and unloading of the truck from a safe vantage point without exposing him to the risk of falling or being struck by the load.
Employers must ensure that a 'person in charge' is appointed to direct or supervise loading operations where lifting equipment is used. This may be the driver of the truck or a competent person nominated at the workplace. Whichever the situation, all persons involved in the loading process should comply with the directions of the person in charge who would normally work closely with the truck driver to determine the most suitable method of loading the truck.
Once the steel product is loaded for transporting, the truck driver assumes the primary responsibility not only for the load he is carrying but also for his own safety and that of the general public. It is therefore essential he be trained in the correct methods of restraining loads.
He should check the securing of the load prior to commencing a journey. If he has any doubt about the security of the load he must advise the person in charge of the loading operation and have the matter rectified.
If the unloading facilities at his destination are not satisfactory he must advise his own supervisor of the situation and ensure that suitable arrangements can be made.