OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION

Transcription

1 Occupational Safety and Health Guides and Instructions 12 Lifting Accessories Safety OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION Tampere 2007

2 ISBN ISSN Multiprint Oy, Tampere 2007

3 Table of Contents INTRODUCTION...5 General requirements for lifting accessories...6 Structure...6 Safety factor...6 Machinery Decision requirements apply also to lifting accessories custom-built for individual uses...6 Use and inspection...7 Procurement...8 Lift planning...8 GUIDANCE AND TRAINING...9 MARKINGS AND LOAD TABLES...9 FACTORS TO OBSERVE DURING LIFTING...11 CHAIN SLINGS...12 Structure...12 Chain...12 Equipment...13 Inspection and rejection criteria for chain slings...15 WIRE ROPE SLINGS...15 General Inspection and rejection criteria for wire rope slings...16 Synthetic round slings and lifting belts...17 Material...17 Markings...18 Working load limit...18 Sharp edges and edge protection...19 Operating instructions for synthetic slings...19 Inspection and condition monitoring of lifting belts and round slings Maintenance and repair...20 LIFTING CLAMPS...21 When using clamps...21 Special operating instructions for screw clamps...22 LIFTING TONGS...22 Inspection...22 LIFTING MAGNETS...23 VACUUM LIFTERS...24 LIFTING FORKS...25 LIFTING BEAMS... 25

4 LOOSE LIFTING GEAR Lifting lugs Lifting lug dimensions Welded lifting lugs Lifting eye bolts and nuts Inspection SHACKLES Inspection Lifting accessories custom-built for individual use Regulations and instructions APPENDIX 1 Lifting accessory inspection report APPENDIX 2 Hand signals Lifting Accessories Safety

5 Introduction Lifting and transfer operations typically entail some risk factors that cannot be totally eliminated. The danger area generally cannot be isolated entirely to prevent the transferred load from causing danger to those participating in the lifting operation or to others nearby. The lifting appliance operator and load handler each play a crucial role in ensuring a safe lifting operation. However, as the lifting appliances used in industry become more and more radio-controlled, the operator increasingly also performs the role of load handler. Compared to many other types of work equipment, lifting appliances have a central role in terms of safety, as failure of practically any one of their parts can result in a hazard situation. The idiom that a chain is only ever as strong as its weakest link also applies well to the lifting operation. The lifting accessory and its operation must be monitored and controlled throughout its lifespan. Failure of even a single link will result in danger. Customers are interested in not only the product itself, but also the operational quality of the company that produces or supplies it. High quality is demanded of production and of the production environment, and a low incidence of damage or accidents is considered by the customer to be a key measure of quality. Provision of clear operating instructions indicates to the customer that quality-conscious and safe operations are being observed. The transfer and transportation of materials and personnel is the main accident black spot for many fields of industry. According to some estimates, nearly half of all industrial accidents are related to lifting or transfer operations. The size and weight of lifted loads has increased, and accidents that occur are often serious in terms of occupational safety as well as financially. Accidents are almost equally influenced by technical factors as human factors. A significant proportion of accidents are considered to be caused by substandard or totally lacking pre-planning, with lift planning too often consisting solely of in-situ arrangements made between the site foreman and the employee. On the other hand, the structural safety of lifting accessories is considered to be reasonably high. Inspections are arranged in a high proportion of companies, but the level and scope of these inspections is variable. Lifting slings are, at least, inspected by the seller, but without the user s own established inspection procedure this can create a false sense of security. Accidents can occur at any time ahead of the next scheduled inspection. Faulty lifting accessories must therefore be immediately identified and repaired or, if necessary, taken out of use completely. Finnish regulations concerning lifting and transfer appliances are based on the Occupational Safety and Health Act. The objective of this publication is to create a data file which can be workplace-specifically supplemented and used to define a set of procedures aimed at ensuring that loads and the lifting of them is better planned, and that employees are competent in the use of safe lifting methods and can fully rely on the lifting accessories they work with. Any procedures found to be beneficial can be incorporated into the company s quality system and occupational safety action plan. These guidelines focus on practical workplace level operations and the models and solutions presented in them are based on the common tasks and problems encountered at this level. The guidelines are based on information gathered from legislation, standards, studies, information from insurance companies and suppliers of lifting accessories, occupational safety and health inspectorates and experts in the field. Information needed at the workplace for the planning of instructions for the procurement and inspection of lifting accessories, the plan- Lifting Accessories Safety 5

6 ning of lifting operations and practical guidance has also been included. The guidelines also aim to take current legislation and other norms and instructions into consideration. The guidelines cover the most commonly used lifting accessories as well as lifting accessories that are custom built for individual, specialised uses. General requirements for lifting accessories Structure The lifting of a load requires a lifting appliance and a lifting accessory. A lifting accessory refers to a component or device that is not permanently fitted to the lifting appliance and that is used between the lifting appliance and the load, or fixed to the load to enable it to be lifted. Requirements concerning the structure of lifting accessories are presented in the Government Decision on the Safety of Machines (1314/1994, as amended) which came into force on 1 January The decision, hereinafter referred to as the Machinery Decision, applies to all lifting accessories taken into use and brought onto the market after 1 January The Machinery Decision requires manufacturers of lifting accessories, their authorized representative established in the European Economic Area or manufacturers that assemble lifting accessories from ready components to draw up a Declaration of Conformity for the lifting accessory and to affix CE marking to it. A Declaration of Conformity can also be given for product batches. Safety factor Lifting accessories each are assigned a specific safety factor. The safety factor consists of a safe working load limit set below a given safety margin. The limit ensures that no immediate danger will occur if the maximum safety load is exceeded. The safety factor does not give the operator licence to exceed the working load limit, rather it provides a safety margin to compensate for the weakening of the lifting appliance during normal use due to wear and ageing, jolting during lifting and inaccuracies in load weight estimations. Machinery Decision requirements apply also to lifting accessories custom built for individual uses Appendix 1 of the Machinery Decision presents the essential safety requirements concerning machinery and Chapter 4 of Appendix 1 of the decision addresses, in particular, the essential safety requirements concerning the structure of lifting accessories. The same chapter also presents, e.g., the working coefficients (safety factors) of different lifting accessories. According to the Machinery Decision, each lifting accessory, attached machine plate or equivalent marking position must be marked with the following: manufacturer s details raw material information, if required for compatibility purposes working load limit CE marking In addition, each lifting accessory or lifting accessory batch sold as a unit must include an instruction manual containing at least the following information: standard operating conditions use, assembly and maintenance instructions restrictions on use Lifting gear such as lifting lugs, lifting eyes and shackles that are used in conjunction with 6 Lifting Accessories Safety

7 the different lifting accessories dealt with in this guide are defined in the Machinery Decision as loose lifting gear and no details regarding their markings are specified. Thus, e.g. CE marking is not required for them. However, from the point of view of safety it is important that they are marked with their working load limit or other marking from which their safe working load can be determined on the basis of the instructions drawn up by the manufacturer. Use and inspection The safe use of equipment such as lifting accessories is laid down in the Government Decision on the procurement, safe use and inspection of workplace machinery and other work equipment (856/1998), hereinafter referred to as the Work Equipment Decision. Chapter 4 of the Work Equipment Decision presents general regulations for the safe use of equipment used for lifting. The reformed Work Equipment Decision (856/1998, as amended) now also includes regulations for the periodic inspections of lifting accessories. The Government Decision on the procurement, safe use and inspection of workplace machinery and other equipment (856/1998, as amended) requires the inspection of lifting accessories at annual intervals. The inspection interval can be lengthened or shortened within reasonable limits on the basis of the degree of strain of use. The employer can appoint a person in their service or an external person with sufficient expertise in the structure, use and inspection of the lifting accessories to carry out the inspections. The inspector must be capable of detecting possible faults and damages and estimating their impact on occupational safety. The manufacturer s instructions must be taken into consideration in the inspections. The inspection typically consists of a visual assessment to ascertain the effect on operational safety of wear, deformation or damage incurred in service. If necessary, the inspection can be supplemented with non-destructive inspection methods. The inspections are recorded in a suitable manner with respect to the needs of the workplace. An inspection record, card index or inspection register can be made, containing essential information on inspection dates, perceived faults and defects and repairs carried out. An inspection marking must be made on each accessory in order to eliminate use of noninspected equipment and to facilitate the carrying out of inspection obligations. An effective means of preventing accidental re-use of lifting accessories that have failed inspection and are beyond repair is to disable them completely. Before bringing a new lifting accessory into use, the device must be checked to verify that it complies in all respects with its operating requirements and is suitable for the purpose of use. Furthermore, the user must check on a daily basis all lifting accessories that are in continuous use. The condition of less frequently used equipment must always be checked each time the equipment is taken into use. The check should consist of a visual inspection to ascertain that the lifting accessory is in due order and all of its parts are fixed together firmly. After overloading or damage, a thorough inspection of the lifting accessory must always be made before it can be used again. The requirements for the site inspection of lifting accessories used in construction work are laid down in the Government Decision on the Safety of Construction Work (629/1994, amendment 427/1999). Chapter 4 of the decision states that the structure and condition of lifting accessories shall be checked at the construction site to find out whether they are appropriate for the purpose of their use and compliant with the requirements. In addition, lifting accessories shall be inspected at the workplace before they are taken into use and at regular intervals during operation and, if possible, at least once per week. The government decision concerning stevedoring work (915/1985, as amended 449/1995) provides special regulations for the use and inspection of lifting accessories used in the loading and unloading of vessels. Lifting Accessories Safety 7

8 Procurement Procured equipment must be suitable for its purpose of use. Operating and maintenance instructions in Finnish and, if necessary, in Swedish must always be obtained from the lifting accessory supplier. Operational safety can be increased by procuring lifting accessories that cannot be accidentally or unknowingly used incorrectly. The procurement of lifting accessories should be concentrated on a few reliable suppliers, as this ensures better provision of advice and expert help and user training if needed. The procurement of new lifting accessories can also be centralised at the workplace. This task is ideally suited, for example, to the lifting accessory inspector who is responsible for registering the lifting accessories in the company s monitoring system. Lift planning The planning of lifting operations should be integrated as part of production s material handling planning, the objective of which is the economical, flexible and safe handling of products. All future lifting requirements should be considered at the product s planning stage. Good lift operation planning and the correct choice of lifting accessory can effectively eliminate the worst operating errors and hazards in advance. The designer of the lifted item must determine how and with which lifting accessories the lift is to be performed, determine the points of lift and, as necessary, add lifting eyes, lifting lugs or threaded holes for fastening lifting eye bolts. At the planning stage, lifting instructions must be prepared for the product. The lifting operations and transfers needed during the different production stages of the product s subcomponents must also be taken into consideration in the lift plan. A set of permanent instructions should be drawn up for the load handling and lifting of frequently recurring similar items. Special lifting operations such as heavy lifts, lifting of large items and joint lifting operations always require a separate written plan. To ensure a balanced lift, the weight, shape, lifting position and centre of gravity of the load must be determined. Mark the weight and centre of gravity of the lifted item in the drawings. The lifted item must be kept balanced and under the control of the lifting appliance operator throughout the lifting operation. To prevent sliding or falling of the lifted item, the load supports, points of attachment and lift route must be planned. Choose a lifting accessory that is compatible with the load, the lifting appliance and the operating environment: - choose a sling that is long enough to guarantee a safe sling angle and prevent overloading - determine how the weight is to be divided between the sling legs - take into account the lifting frequency - reserve sufficient room for the lifting operation - use edge protection as necessary. Check the landing platform and the load supports to ensure that the lifting accessories can be removed both safely and without damage. If necessary, perform a test lift to verify the secure fastening of the load. Ensure the lifting accessories are inspected and necessary user guidance is provided. 8 Lifting Accessories Safety

9 Guidance and training In order to avoid accidents, personnel involved in lifting operations must be provided with training and guidance in safe lifting practices appropriate to the work quality and working conditions in question. Effective work guidance can influence employee attitudes towards safety. Right attitudes can prevent accidents. Risk factors should be analyzed and written manuals drawn up as necessary. Responsible persons and spheres of responsibilities must be clearly defined. The employee must observe all instructions, regulations and take due care in their operations. The employee must also notify the foreman and occupational safety and health representative of any perceived faults or deficiencies. A record should be kept of all lifting operation training and guidance provided. This enables monitoring and checking of the type and date of guidance and/or training received by each employee. It also facilitates the planning of new and supplementary training and helps avoid overlapping of training content. Markings and load tables Each lifting accessory must be marked with its designated working load limit. The lifting accessory must not be used if this marking is not displayed. Overloading is forbidden at all times. A suitable sling type must be chosen and its loading instructions strictly observed. The greater the angle of inclination of the sling legs (sling angle), the less load the sling can support. The correct sling angle can be determined via load tables. Use of load tables must be mastered by all lifting operation personnel. In the new standards and tables, the angle of inclination of the sling leg (sling angle) refers to the angle ß between the sling leg and the vertical. A higher than 60 angle of inclination (120 leg angle, i.e. angle between sling legs, according to the former system) must not be used. The angle of inclination ß equals half the leg angle α. The working load limit for a multi-legged sling depends on the number of sling legs and the sling angle factor as determined by the angle of inclination and the leg configuration (hitch). Outdated load markings should be changed in accordance with the new standards to avoid confusion. Harmonised practices at the workplace should be adopted in a controlled manner and through provision of employee training. Lifting Accessories Safety 9

10 Figure 1 Angle of inclination (sling angle) ß / angle between sling legs Table 1 Finnish standard SFS 5152 compliant load table for chain slings Chain diameter mm Single-leg sling Double-leg sling Multi-leg sling Straight lift Choked lift Straight lift Choked lift Straight lift Choked lift Straight lift Straight lift Sling angle factors used in the calculation of working load limits 10 Lifting Accessories Safety

11 Factors to observe during lifting The hook of the lifting appliance and lifting accessory must be equipped with a safety latch or other reliable backup such as a selflocking hook. For each lifting operation, check that the master link is compatible (i.e. big enough) with the lifting appliance s hook. The weight and centre of gravity of the lifted load must be known. Ensure that the lifting sling used is long enough. The distance between the points of attachment must be big enough to ensure a secure load balance during lifting. Sliding of the sling must be prevented using a lifting boom as necessary. Never lift or move the load over personnel or leave the load unnecessarily suspended. Ensure that the load is set squarely in the bowl of each sling hook to avoid incorrect loading of the hooks. Take into account the effect of choker lifting: reduces the working load limit by 20%. Protect the sling from any sharp load edges. Lifting slings, especially round slings and lifting belts, are susceptible to damage from sharp load edges. Sharp edges can significantly weaken the strength of the lifting accessory and present a sudden hazard. The best form of protection against sharp edges is the use of edge padding designed for this purpose. Any sharp edges on the load should, as far as possible, be removed at the production stage. A preliminary lift should always be carried out: once the load is raised free of its base, stop the lift and check the load balance and fastenings. Avoid jolting during loading (e.g. due to sudden starts and stops), and never swing laterally, lift laterally or drag the load along the ground. Never attempt to manually stop a heavy load from swinging. Never lift using the bindings used for bundling the load if they are intended only for load binding. Never pull a sling from beneath the load if the load is resting on the sling. Store slings in their designated storage places. Lifting Accessories Safety 11

12 Chain slings Structure Chain slings are lifting accessories comprised of a chain and connected lifting gear. They can be single or multi-legged. Each sling must be fitted with a marking plate displaying the working load limits for different loading situations. A visual inspection must be carried out before using the sling to verify that the sling and sling fittings are in due order. Chain slings can typically be used at maximum load in a temperature range of -40 C to +200 C. The manufacturer s instructions must be observed for operation in temperatures outside this range. Chain slings should have a designated storage place (e.g. rack) where they are not susceptible to damage and can be easily obtained. Load tables and lifting instructions should also be located at the storage place. Figure 2 Chain slings Chain The chain consists of steel links. Lifting slings must be made of short link chain only. Figure 3 Chain The required properties of the chain are stipulated in the relevant standards for sling chains. Documents specifying the technical properties of the chain must be readily available during chain sling assembly. Any fittings attached to the sling must be at least as strong as the chain itself. 12 Lifting Accessories Safety

13 Equipment Master link One or more sling legs are connected to the master link via a suitable connection method. Figure 4 Master links For each lifting operation, check that the master link is compatible with the lifting appliance s hook (i.e. big enough). Hook Sling hooks must consist of self-locking hooks or sling hooks equipped with a sufficiently strong safety latch. Figure 5 Different hook models Open hooks may be used only in special cases where it is ensured that no hazard to personnel, nearby objects or materials will be created during the lifting operation. The load must always be set squarely within the hook bowl. The hook s safety latch must be of sufficient strength and laterally supported to be able to fully withstand the loading and operating stresses. Lifting Accessories Safety 13

14 Other equipment Mechanical connector Connectors are used in chain sling assemblies to connect its various components. The hitch configuration system ensures that components of the wrong size cannot be connected to each other. Sling importers each supply connectors that are compatible with their own chains. Figure 6 Examples of mechanical connectors Marking plate Each chain sling must be fitted with a marking plate showing its designated working load limit. The marking plates of standard SFS-EN compliant slings contain the information shown in Figure 7. Figure 7 Chain sling marking plate 1. Working load limit 2. Nominal chain diameter 3. Number of sling legs 4. Sling angle marking 5. CE marking Shorteners In order to balance the load, length adjustment of the chain sling legs is needed. Shorteners consist of shortening clutches, shortening hooks or quick-acting chain length regulators which lock the chain in place with spring-loaded pegs. Figure 8 Slings equipped with different types of chain shorteners The impact of shortening hooks on the chain s strength must be verified and users informed of any restrictions. Before beginning the lifting operation, check that the chain is securely locked in the shortener and unable to come loose at any stage during the lift. 14 Lifting Accessories Safety

15 Inspection and rejection criteria for chain slings Chain slings must be measured and their entire length inspected during periodic inspections. The lengths of the different legs of multi-legged slings must be compared. Special consideration must be paid to possible stretching, wear, cracking, deformation and external damage of the different sling parts. Detailed link-by-link inspection is the only means of detecting these damages. The cause of the perceived damage must always be clarified and steps taken to prevent the fault from recurring. The inspection must be made in accordance with the manufacturer s instructions. Chain sling inspections are usually based on the following rejection criteria: A chain sling must be taken out of use if: The sling s working load limit for different load situations is not clearly marked on the sling. The sling s master link, hooks or other components contain bends, fractures, warping, other deformation or the hook mouth has opened more than 10%. Any chain link has worn more than 10%. The chain links are measured in two planes. Their average dimensions must be at least 90% of their original dimensions. In this way, the level of wear until the next inspection can be predicted. Slashing, notching, pitting or corrosion caused by external factors is more than 10% of the material thickness, or the degree of deformation is visually perceptible. Colour change caused by heat damage is perceived. Damage caused by weld splash is perceived. The mechanical connector is worn, bent, warped or cannot turn freely. Wire rope slings General Wire rope slings are lifting accessories made from steel rope with a ferrule-secured or spliced sling eye at each end. Sling eye fittings include links and hooks. When using eye fittings and attachments, eye thimbles must be used to protect the sling eye. Wire rope slings can be single-legged or multi-legged. Figure 9 Typical wire rope slings Always carry out a visual check before using the sling to ensure that it contains no faults that may jeopardise safety. The interval between periodic inspections depends on the degree of strain of use. Lifting Accessories Safety 15

16 During periodic inspection, check the condition of the sling paying particular attention to its markings and any damage or wear that may affect the safe use of the sling. working load limit marking for different loading situations broken or worn wires rope deformation (e.g. kinks, bird caging) warped ferrules, splices or terminations heat damage corrosion In addition to a visual inspection, other methods must be used as necessary, such as non-destructive testing to determine the condition of the inner parts of the sling. Inspection and rejection criteria for wire rope slings Wire rope slings must be inspected along their entire length during periodic inspection. Special consideration must be paid to possible stretching, wear, cracking, deformation and external damage of the different sling parts. The cause of the perceived damage must always be clarified and steps taken to prevent the fault from recurring. The inspection must be made in accordance with the manufacturer s instructions. Wire rope sling inspections are usually based on the following rejection criteria: Broken wires Wire breaks are usually caused by mechanical damage or corrosion. They reduce the strength of the rope and can cause hand injury to the user. The sling must be rejected and replaced if any strands are totally broken, wire breaks occur very close to each other or the number of wire breaks exceeds 5% of the total number of wires along a length equal to six times the diameter of the rope. The sling must be rejected if the nominal diameter of the rope has worn by more than 10% at any point. Rusting and corrosion Corrosion may occur if the sling is incorrectly stored or used in corrosive conditions. Surface rusting may also be a sign of internal corrosion, the extent of which is difficult to estimate. In this case the rope must be opened up to assess its internal condition. The sling must be rejected if a significant degree of internal corrosion is found, or corrosion is found in the splice. Deformation The sling must be rejected if it contains deformation caused by kinks, bird caging, crushing, core failure or knots. Heat damage Colour changes of steel ropes can be a sign of overheating. Overheating damages the fibre core and weakens the rope s lubrication. The manufacturer s instructions must be observed regarding the permissible operating temperatures. Damage of sling eye fi ttings and attachments Special attention must be paid to the following points: opening up and cracking of hooks deformation and wear of links or thimbles ferrule cracks crushing or wear of ferrule or splice slide-through or looseness of splice or ferrule wire breaks concentrated near the ferrule or splice or in the splice the effect of the sling eye spreading force at the head of the sling eye if an oversized pin or wrong thimble type is used breaking wires on the outer surface of the sling eye, e.g. if a soft eye and thin pin has been used effect of friction on the load-bearing surface of soft sling eyes. 16 Lifting Accessories Safety

17 Synthetic round slings and lifting belts The use of round slings and lifting belts made from synthetic fibre has become increasingly widespread. They are easy to use due to their lightness and their surface quality is well suited to the lifting of delicate materials. On the other hand, they are more susceptible to damage than other slings. There are fundamental differences between round slings and lifting belts. Confusing the two can, in certain situations, be hazardous. The most essential difference is in their inner structure. The load-bearing yarns of belts are woven into a band, whereas round slings consist of endless loops of load-bearing yarn enclosed within a tubular cover. Figure 10 Lifting belts Figure 11 Round sling Material Lifting belts and round slings are made from synthetic fibre yarns made of either polyester, polyamide or polypropylene. The most common yarn material used in Finland is polyester. The sling material must also be UV radiation protected. The material properties of synthetic fibre round slings and belts are rarely considered at the procurement stage. The user must, nevertheless, at least understand the effect of the lifting site conditions on the lifting accessory. Is the site exposed to high temperatures? How might any chemicals used affect the sling/belt? Is there UV exposure? Do the lifted loads have sharp edges? The sling/belt material is indicated by the sling label colour-coding: Polyester = blue label Resistant to weak acids, but damaged by alkalis. Polyamide = green label Resistant to alkalis, but weakened even by weak acids. Weakens upon wetting. Polypropylene = brown label The most suitable of the three materials where chemical resistance is needed. Resistant to acids and alkalis. Non-resistant to some solvents. More detailed information on the chemical tolerances of belts and slings is provided by the manufacturer. Lifting Accessories Safety 17

18 Markings Round slings and lifting belts must have the following markings: manufacturer s/seller s details nominal strength = WLL (working load limit: nominal loads under 1,000 kg are expressed in kilograms and nominal loads above 1,000 kg in tonnes). safe working load (working load limit) at different sling angles sling/belt material indicated by coloured label. CE marking length traceability code must be available. A double marking label can also be used, i.e. a backup label is fixed beneath the stitched marking label. The following documents must be readily available: operation, assembly and service instructions Declaration of Conformity, including: name and address of manufacturer or supplier description of sling/belt applied standards Working load limit The sling angle factors and working load limits for different sling angles are shown in the instruction tables provided by the manufacturer or importer. These tables should be kept at the site of use of the lifting slings. Table 2 Sling angle factors for round slings Straight lift Choked lift Basket lift Basket lift WLL 0,8 WLL 2 WLL 1,4 WLL 1 WLL 0,7 WLL 0,5 WLL Table 3 Sling angle factors for lifting belts Straight lift Choked lift Basket lift Basket lift WLL 0,8 WLL 2 WLL 1,4 WLL 1 WLL 18 Lifting Accessories Safety

19 Sharp edges and edge protection Contact of the lifting sling with sharp edges during the lifting operation dramatically reduces the sling s strength. Burs, load imbalance, stop/start jolting during lifting or worn slings further increase the damaging effect of sharp edges. A sharp edge with a corner radius of 1-7 mm reduces the load-bearing capacity of lifting belts and round slings by 50%. With lifting belts, a 13 mm corner radius is required to maintain a load-bearing capacity close to that of straight lifting. According to experience, edge protection must be used whenever the corner radius is below 7 mm. A wide range of edge protection types and materials are available for specific applications. Operating instructions for synthetic slings Before lifting, perform a visual inspection of the full length of the sling and check that the working load limit is clearly marked. Only use slings that are in full working order. Take into account the effect of the lifting method on the load. Do not exceed the working load limit. Be wary of sharp edges and coarse surfaces. Use edge protection. Ensure the load remains balanced for the entire lifting and transfer operation. The lifting hook must be big enough with respect to the belt width and the hook edges must be rounded off. Ensure that the sling is set squarely in the bowl of the hook and is evenly loaded. The leg angle of hooked eye belts must not exceed 20 degrees. Never tie knots in the sling. Knots weaken the strength of the sling, endanger the lifting operation and may ruin the sling. For load temperatures over 80 C follow the manufacturer s instructions. Chemicals and solvents can damage the sling. Avoid sharp stops/starts by slowly accelerating and decelerating during the lift. Avoid any kind of jolting during the lifting operation. Lower the load onto its landing platform so that the sling can be removed without damaging it. Do not forcefully remove the sling. If multiple slings must be used simultaneously due to the length of the load, prevent sliding of the lifting accessory in the lifting hook and on the load. Inspection and condition monitoring of lifting belts and round slings Lifting belts and round slings are more susceptible than other lifting accessories to damage and must therefore always be condition checked before each use. Lifting belts must be visually inspected along their entire length on both sides for surface damage, longitudinal or transverse band cutting, edge cutting, wear damage and stitch or eye damage. The condition of round slings must be estimated according to the condition of their outer coating, as the load-bearing yarns are sealed within the coating. In addition to visual inspection, the condition of the load-bearing yarns must be felt to verify that they are free of any hardening and that the core is regular in shape. Some hardened areas felt inside the sling may be due to tape bindings used in round sling manufacture. Users of lifting belts and round slings must be given sufficient guidance in their condition assessment. In addition, a competent expert must check the condition of the slings at least once a year and verify their suitability for use with respect to the existing lifting conditions. One-time-use slings are often supplied with new machinery for purposes of moving it and lifting it into position. These throwaway slings must be disposed of immediately after use. Lifting Accessories Safety 19

20 A lifting belt must be taken out of use if: The working load limit marking is not clearly visible. The belt has been overloaded. The belt contains a knot. The belt has extensive abrasion damage or is generally worn and dirty. More than 10% of the warp yarns (loadbearing yarns) are severed or yarns are damaged on the belt edge. The weft yarns are broken along a more than 5 cm length. Slash damage or abrasion damage of the surface exceeds 10% of the transverse direction. Damage has been caused by chemicals, heat or moisture. Yarn breaks exist at the belt terminations or the terminations are considerably worn. The joint stitching has come unstitched. A round sling must be taken out of use if: The working load limit marking is not clearly visible. The sling has been overloaded. The sling contains a knot. The outer coating is broken to the extent that the inside is visible. The outer coating shows signs that a welding spark, lathe chip or equivalent has damaged the load-bearing yarns. The sling cover has extensive abrasion damage or is generally worn and dirty. Damage to the load-bearing yarn has been caused by chemicals, heat or moisture. Maintenance and repair Do not attempt to carry out repairs yourself. Dirtied lifting belts and round slings can be washed in tepid water using a neutral detergent. Lifting belts and round slings that have been wetted during washing or otherwise must be left to dry in either a hanging or laying position. They must not be spin-dried. Store synthetic slings in a well ventilated space on a rack designed for the purpose so that they are not susceptible to chemicals, solvents, ultraviolet radiation, temperatures over 70 C or varying climatic conditions. Remember to only use round slings and lifting belts that fulfil strict quality requirements. Observe the instructions provided by the manufacturer and refer any problems encountered to the manufacturer. The inside of the sling is damaged. 20 Lifting Accessories Safety

21 Lifting clamps Clamps are used for lifting plates and sheets, profiled products and pipes. The holding force is typically based on the grip between the clamp s toothed eccentric cam and the surface of the lifted item. Figure 12 Lifting clamps 1. Body 2. Lifting eye 3. Cam segment 4. Safety latch 5. Spring 6. Cam segment shaft 7. Lifting eye shaft 8. Pivot Lifting clamps must show the following markings: working load limit minimum and maximum thickness or width of lifted items production/serial number name of manufacturer/supplier CE marking In addition, the clamp must be marked with any possible use restrictions. The operating instructions, maintenance and inspection instructions and Declaration of Conformity included with each clamp delivery must be observed. Clamps that are not equipped with safety locking to safeguard against accidental loosening of the load must not be used for vertical lifting of plates or sheets. When using clamps Check that the clamp is in order and suitable for use and that the surface hardness of the lifted item does not exceed the maximum surface hardness permitted for the clamp. The clamp must be compatible with the lifting appliance s hook and, if necessary, a chain sling with a sufficiently large ring must be used. Do not exceed the working load limit. Check that the contact surface is free of scale, paint, dirt, ice, grease or other substances that may weaken the holding capacity. Always observe the designated loading direction of the clamp. The clamp must be positioned to follow the lifting direction of the sling. Pendular motion of the fastened item must be prevented, as this can damage the clamp s cam teeth. When lifting long plates or sheets, two or more clamps and lifting booms should be used. Lift only one plate or sheet at a time when vertical lifting with a plate/sheet lifter. Lifting Accessories Safety 21

22 At least two pairs of horizontal clamps should be normally used. Do not exceed the maximum sling angle specified by the clamp manufacturer. When turning or moving, always keep the end of the plate/sheet or lifted load towards you. Lifting above personnel is strictly forbidden. Wear of the contact surfaces of the lifting clamp s cam segment and counter jaw must be monitored and inspection intervals shortened as necessary. If the clamp has undergone repair, its operation must be checked by means of a test lift. Special operating instructions for screw clamps The clamp must be compatible with the lifting task. For example, clamps that base their holding capacity solely on the manual tightening force of the screw must not be used for vertical lifting of plates or sheets. The holding force is based on the friction force between the cam segments and the surface of the lifted item, so the clamps must have toothed, hardened cams. The optimum holding force is attained if the cam section includes a swivel joint that wedges the jaw more tightly closed as lifting commences. Lifting tongs Lifting tongs are used for lifting round parts or bundles. Their holding force is based on the curved shape of their arms and the leverage effect. The broader the tongs, the better their holding capacity. Their holding capacity can be improved by coating the gripping arms to increase friction. The specified working load limit for the tongs must not be exceeded. The load diameter must also conform to the specified maximum/minimum limits. The same documentation must be observed upon delivery of the tongs as with clamps. Figure 13 Lifting tongs Inspection Observe the instructions provided by the manufacturer, paying special attention to deformation, warp and cracking. Check the operation of the tongs and their locking function (should lock when in the open position), the tightness of the screws, shaft wear and the tong markings. 22 Lifting Accessories Safety

23 Lifting magnets There are two basic types of lifting magnet on the market: permanent magnets and electromagnets. In addition, electrically connected permanent magnets offer a third, intermediate alternative. Electromagnets include mains current and standby battery operated accumulator models. The advantage of permanent magnets is their minimal maintenance and simple structure. Figure 14 Lifting magnets 1. Magnet 2. Instruction plate + type plate 3. Lifting eye 4. Release arm 5. Release button 6. Pole shoes The lifting capacity of lifting magnets is derived from the magnetic field that forms between the magnet and the lifted item. Factors affecting the size of this magnetic field and, thus, the load holding power include: Lifting capacity reduces with reduced contact surface area of the magnet shoes. The magnet shoes must be clean and smooth. They must not be machined. Any irregularities must be carefully ground smooth. Thin-walled items do not create an effective magnetic field. The surface quality of the lifted item. Air gaps strongly reduce the lifting capacity. Air gaps result from surface unevenness, burs, scale, grease, paint etc. The shape of the lifted item. When lifting round and curved items, rounded pole shoes must be used to achieve a sufficient contact surface. In this case the lifting capacity is always lower than when lifting flat items. The overall dimensions of the lifted item. Long items tend to bend, creating air gaps at the edges of the magnet. Position of the magnet. Standard magnets can be lifted only in the horizontal position. Variable magnetism of lifted items. Some materials do not magnetize at all. The optimum holding capacity is attained with unalloyed low-carbon steel. The weight of the lifted load must be proportioned according to the magnet manufacturer s instructions. Magnets must not be used in high temperatures. The manufacturer s instructions must be observed in this respect. The holding capacity of the magnets must be checked at regular intervals by test lifting using the same loads typically lifted by the lifting magnets. Lifting Accessories Safety 23

24 Vacuum lifters The vacuum lifter is a lifting accessory equipped with one or more suction cups. The adhesive force between the load and the suction cup is created by means of a vacuum. Vacuum lifters usually operate by means of vacuum pumps, blowers or ejectors but they can also be mechanically operated without a pump. The shape of the suction cup is selected according to the shape and quality of the load, e.g. round, angular or oval. The suction cups can be flat, for lifting flat items such as plates, sheets, panels and glass panes. The contact surface of the suction cups can also be specially moulded for the lifting of pipes or other non-flat items. In addition to the required lifting capacity, the shape of the lifted load and its surface quality must also be taken into consideration in the choice of vacuum lifter. Lifters should be designed to provide double the holding capacity required for the heaviest load lifted. Vacuum lifters may not be used for conveying hazardous materials. Loaded lifters must never be lifted above personnel. If necessary, the danger area must be isolated. Figure 15 Vacuum lifters a) piston b) cylinder c) sealing ring d) vacuum chamber e) valve f) reverser g) torque rod h) chain i) rubber diaphragm j) pressure chamber k) alarm whistle l) dust cover m) bleed valve 24 Lifting Accessories Safety

25 Lifting forks The same rules apply to lifting forks as to other lifting accessories. Most hazardous situations that arise when operating lifting forks involve falling loads. Attention must therefore be paid in the design and user instructions of the lifting fork to ensure sufficient fastness and stability of the load during the lifting operation. User instructions and a Declaration of Conformity must be included in the lifting fork delivery. During periodic inspection of the lifting fork, visually check for any permanent deformation of the structures and wear of the wearing parts. Check the joints of the structure, especially welded joints, to ensure there are no visually apparent cracks. If the lifting fork operation involves any mechanical functions that stabilise A wide range of different loading capacities, shapes and lengths of lifting beam are available. Lifting beam components and other equipment should also be optimally designed to suit the beam s specific function. Lifting beams or spreader beams can effectively reduce the load stresses on the sling or on the load itself. Lifting beams are the ideal lifting accessories for workspaces with limited headroom where the use of lengthy top rigging is not possible. The lifting beam designer and manufacturer must have the necessary expertise in lifting beam design and production, including suffithe lifting fork or load during the lifting operation, the functions and the wear of the components involved must also be inspected. Figure 16 Standard lifting fork Lifting beams Figure 17 Lifting beams cient knowledge of material strengths and structural requirements. Lifting beams must have the following markings: working load limits for different loading situations dead weight of the beam, to enable determination of the lifting appliance s payload capacity production/serial number, name of manufacturer and CE marking The following must be observed upon delivery of the lifting beam: operating instructions, including possible restrictions on use maintenance and inspection instructions and assembly drawing Declaration of Conformity Lifting Accessories Safety 25

26 LOOSE LIFTING GEAR Lifting lugs Lifting lug dimensions The dimensioning of lifting lugs takes into account the loads exerted on them. For example, the force exerted on the sling leg is also exerted on the lifting lug in the direction of the sling leg. In single-legged direct lifting, the full weight of the lifted load is exerted on the lifting lug. Dimensioning must also take into account possible asymmetry of the load, in which case the load will not be exerted evenly on all lugs. In addition, it must be ensured that the load itself can withstand the stresses exerted on it. If the lifting lugs are used as loose lifting gear (i.e. not welded), they must either be marked with their working load limit or their rated capacity and possible restrictions on use must be specified in the operating instructions provided upon delivery. Welded lifting lugs The traditional lug model consists of a bracket thermally cut from steel plate with a hole for Figure 18 Welded lifting lug shackle attachment. The design must take into account the load exerted on the lifting lug, the loading direction and the suitability of the point of attachment to a welded joint. Welded lifting lugs designed and manufactured to withstand loading in all directions according to the rated capacity marked on the lug are also available on the market. These lugs usually consist of a round, high-tensile lug and weldable fastening pieces. Lifting eye bolts and nuts Lifting eye bolts are loose lifting gear. They must either be marked with their working load limit or their rated capacity and possible restrictions on use must be specified in the operating instructions provided upon delivery. The model that is still extensively used is the DIN580 and DIN582 compliant lifting eye bolt. The bolt can be loaded only vertically or at an angle of max. 45 degrees in the direction of the lug eye. Figure 19 Lifting eye bolt 26 Lifting Accessories Safety

27 The safest models are those marked with working load limits set within sufficient safety margins in all loading directions. The lug eye should also be able to swivel freely after fastening, so the screw itself is protected from loosening or over-tightening under stress. Inspection Visually check that the thread of the eye bolt and fastening hole are intact and that the eye bolt is free of deformation. Shackles Shackles used for lifting must be designed for the lifting task in question. Shackles are loose lifting gear. As such, they must either be marked with their working load limit or their rated capacity and possible restrictions on use must be specified in the operating instructions provided upon delivery. Always fully tighten the shackle pin before lifting. Fixed joints and attachments that can- not be continuously monitored must be fitted with e.g. a cotter to prevent the pin from opening. Loading of the shackles should be perpendicular to the pin. Inspection Visually check that the pin thread is intact and that the shackle is free of fracture or deformation. Figure 21 Shackles Lifting Accessories Safety 27