Occupational Safety and Health Guides and Instructions 12
Lifting Accessories
Safety
ISBN 978-952-479-064-2 ISSN 1456-3614
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 ... 15
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 ... 19
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
Table of Contents
LOOSE LIFTING GEAR ... 26
Lifting lugs ... 26
Lifting lug dimensions ... 26
Welded lifting lugs ... 26
Lifting eye bolts and nuts ... 26
Inspection ... 27
SHACKLES ... 27
Inspection ... 27
Lifting accessories custom-built for individual use ... 28
Regulations and instructions ... 28
APPENDIX 1 Lifting accessory inspection report ... 29
Introduction
Lifting and transfer operations typically entail some risk factors that cannot be totally elimi-nated. 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 op-eration. However, as the lifting appliances used in industry become more and more radio-con-trolled, 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 situa-tion.
The idiom that a chain is only ever as strong as its weakest link also applies well to the lift-ing operation. The liftlift-ing 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. Provi-sion 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 fi elds 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 in-creased, and accidents that occur are often serious in terms of occupational safety as well as fi nancially. Accidents are almost equally infl uenced by technical factors as human fac-tors. A signifi cant 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 arrange-ments made between the site foreman and the employee.
On the other hand, the structural safety of lifting accessories is considered to be reason-ably 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 se-curity. Accidents can occur at any time ahead of the next scheduled inspection. Faulty lifting accessories must therefore be immediately iden-tifi ed and repaired or, if necessary, taken out of use completely.
Finnish regulations concerning lifting and transfer appliances are based on the Occupa-tional Safety and Health Act.
The objective of this publication is to create a data fi le which can be workplace-specifi cally supplemented and used to defi ne a set of pro-cedures aimed at ensuring that loads and the lifting of them is better planned, and that em-ployees are competent in the use of safe lifting methods and can fully rely on the lifting acces-sories they work with.
Any procedures found to be benefi cial can be incorporated into the company’s quality sys-tem and occupational safety action plan.
These guidelines focus on practical work-place 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 sup-pliers of lifting accessories, occupational safety and health inspectorates and experts in the fi eld.
Information needed at the workplace for the planning of instructions for the procurement and inspection of lifting accessories, the
plan-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 acces-sories that are custom built for individual, spe-cialised 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 fi tted to the ing appliance and that is used between the lift-ing appliance and the load, or fi xed to the load to enable it to be lifted.
Requirements concerning the structure of lifting accessories are presented in the Gov-ernment Decision on the Safety of Machines (1314/1994, as amended) which came into force on 1 January 1995. The decision, herein-after referred to as the Machinery Decision, ap-plies to all lifting accessories taken into use and brought onto the market after 1 January 1995.
The Machinery Decision requires manufac-turers of lifting accessories, their authorized representative established in the European Eco-nomic Area or manufacturers that assemble lift-ing accessories from ready components to draw up a Declaration of Conformity for the lifting accessory and to affi x CE marking to it.
A Declaration of Conformity can also be given for product batches.
Safety factor
Lifting accessories each are assigned a specifi c 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 coeffi cients (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 ac-cessory batch sold as a unit must include an instruction manual containing at least the fol-lowing 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
• • • • • • •
the different lifting accessories dealt with in this guide are defi ned in the Machinery Decision as loose lifting gear and no details regarding their markings are specifi ed. 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 acces-sories is laid down in the Government Decision on the procurement, safe use and inspection of workplace machinery and other work equip-ment (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 Deci-sion (856/1998, as amended) now also includes regulations for the periodic inspections of lifting accessories.
The Government Decision on the procure-ment, 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 suffi cient expertise in the structure, use and inspection of the lifting accessories to carry out the inspec-tions. The inspector must be capable of detect-ing possible faults and damages and estimatdetect-ing their impact on occupational safety.
The manufacturer’s instructions must be taken into consideration in the inspections. The inspection typically consists of a visual as-sessment 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 suit-able manner with respect to the needs of the workplace. An inspection record, card index or inspection register can be made, contain-ing 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 non-inspected equipment and to facilitate the carry-ing out of inspection obligations.
An effective means of preventing acciden-tal 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 fi xed together fi rmly. 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 deci-sion states that the structure and condition of lifting accessories shall be checked at the con-struction site to fi nd out whether they are ap-propriate for the purpose of their use and com-pliant 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 steve-doring work (915/1985, as amended 449/1995) provides special regulations for the use and inspection of lifting accessories used in the load-ing and unloadload-ing of vessels.
Procurement
Procured equipment must be suitable for its purpose of use. Operating and maintenance in-structions in Finnish and, if necessary, in Swed-ish 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 ide-ally 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 han-dling planning, the objective of which is the economical, fl exible and safe handling of prod-ucts. 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 elimi-nate the worst operating errors and hazards in advance. The designer of the lifted item must determine how and with which lifting acces-sories 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 instruc-tions 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 consid-eration 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 op-erator 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 suffi cient 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.
• • • • • •
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 infl uence em-ployee 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 responsi-bilities must be clearly defi ned.
The employee must observe all instructions, regulations and take due care in their opera-tions. The employee must also notify the fore-man and occupational safety and health repre-sentative of any perceived faults or defi ciencies.
A record should be kept of all lifting opera-tion training and guidance provided. This ena-bles 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 great-er 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 confi guration (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.
Table 1 Finnish standard SFS 5152 compliant load table for chain slings Figure 1 Angle of inclination (sling angle) ß / angle between sling legs
Sling angle factors used in the calculation of working load limits Chain
diameter mm
Single-leg sling Double-leg sling Multi-leg sling
Choked lift Straight lift Choked lift Choked lift Straight lift Straight lift Straight lift Straight lift
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 self-locking 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 attach-ment 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 lift-ing belts, are susceptible to damage from sharp load edges. Sharp edges can signifi -cantly weaken the strength of the lifting ac-cessory 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 bun-dling 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. • • • • • • •
Chain slings
Structure
Chain slings are lifting accessories comprised of a chain and connected lifting gear. They can be sin-gle or multi-legged.
Each sling must be fi tted 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 fi ttings 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.
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 suffi ciently 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 suffi cient strength and laterally supported to be able to fully withstand the loading and operating stresses.
Other equipment
• Mechanical connector
Connectors are used in chain sling assemblies to connect its various components.
The hitch confi guration 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 fi tted with a marking plate showing its designated working load limit. The marking plates of standard SFS-EN 818-4 compliant slings contain the information shown in Figure 7. Figure 7
Chain sling marking plate
• 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 verifi ed 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.
1. Working load limit 2. Nominal chain diameter 3. Number of sling legs 4. Sling angle marking 5. CE marking
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 considera-tion 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 clarifi ed and steps taken to pre-vent the fault from recurring.
The inspection must be made in accordance with the manufacturer’s instructions. Chain sling inspections are usually based on the fol-lowing 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 com-ponents 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 fi ttings include links and hooks. When using eye fi ttings and attach-ments, 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.
During periodic inspection, check the condition of the sling paying particular attention to its markings and any damage or wear that may af-fect 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-destruc-tive 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 stretch-ing, wear, crackstretch-ing, deformation and external damage of the different sling parts. The cause of the perceived damage must always be clarifi ed and steps taken to prevent the fault from recur-ring. The inspection must be made in accord-ance 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 di-ameter 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 inter-nal corrosion, the extent of which is diffi cult to estimate. In this case the rope must be opened up to assess its internal condition.
The sling must be rejected if a signifi cant degree of internal corrosion is found, or corro-sion is found in the splice.
✔
Deformation
The sling must be rejected if it contains defor-mation 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 fi bre core and weakens the rope’s lubrication. The manufacturer’s instructions must be observed regarding the permissible operating tempera-tures.
✔
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.
• • • • • • • • •
Synthetic round slings and lifting belts
The use of round slings and lifting belts made from synthetic fi bre has become increasingly wide-spread. 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 fi bre yarns made of either polyester, polya-mide or polypropylene. The most common yarn material used in Finland is polyester. The sling ma-terial must also be UV radiation protected.
The material properties of synthetic fi bre round slings and belts are rarely considered at the pro-curement stage. The user must, nevertheless, at least understand the effect of the lifting site condi-tions 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.
Markings
Round slings and lifting belts must have the fol-lowing 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 dif-ferent 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 fi xed beneath the stitched marking label. • • • • • • •
Table 2 Sling angle factors for round slings
The following documents must be readily avail-able:
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 in-struction tables provided by the manufacturer or importer. These tables should be kept at the site of use of the lifting slings.
• • • • •
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 0,7 WLL 0,5 WLL
Straight lift Choked lift Basket lift Basket lift
Sharp edges and edge protection
Contact of the lifting sling with sharp edges during the lifting operation dramatically re-duces 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 lift-ing belts and round sllift-ings by 50%. With liftlift-ing 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 be-low 7 mm.
A wide range of edge protection types and materials are available for specifi c 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 en-tire 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 accelerat-ing and decelerataccelerat-ing duraccelerat-ing 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 dam-aging it. Do not forcefully remove the sling. If multiple slings must be used simultane-ously 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 suscepti-ble 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 cut-ting, edge cutcut-ting, wear damage and stitch or eye damage.
The condition of round slings must be esti-mated according to the condition of their outer coating, as the load-bearing yarns are sealed within the coating. In addition to visual inspec-tion, 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 suffi cient 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.
• • •
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 (load-bearing yarns) are severed or yarns are dam-aged on the belt edge.
The weft yarns are broken along a more than 5 cm length.
Slash damage or abrasion damage of the sur-face 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 inside of the sling is damaged.
• • • • • • • • • • • • •
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 dam-age 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 deter-gent.
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, sol-vents, ultraviolet radiation, temperatures over 70°C or varying climatic conditions.
Remember to only use round slings and lift-ing belts that fulfi l strict quality requirements. Observe the instructions provided by the manu-facturer and refer any problems encountered to the manufacturer. • • • • •
Lifting clamps
Clamps are used for lifting plates and sheets, profi led products and pipes. The holding force is typi-cally 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 in-structions, maintenance and inspection instruc-tions and Declaration of Conformity included with each clamp delivery must be observed. Clamps that are not equipped with safety lock-ing to safeguard against accidental loosenlock-ing 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 suffi ciently 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 di-rection 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.
• • • • • •
At least two pairs of horizontal clamps should be normally used. Do not exceed the maximum sling angle specifi ed 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 forbid-den.
Wear of the contact surfaces of the lifting clamp’s cam segment and counter jaw must be monitored and inspection intervals short-ened as necessary.
If the clamp has undergone repair, its opera-tion must be checked by means of a test lift.
•
•
•
•
Special operating instructions
for screw clamps
The clamp must be compatible with the lift-ing task. For example, clamps that base their holding capacity solely on the manual tight-ening 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 specifi ed working load limit for the tongs must not be exceeded. The load diameter must also conform to the specifi ed maximum/mini-mum limits.
The same documentation must be observed upon delivery of the tongs as with clamps.
Inspection
Observe the instructions provided by the manu-facturer, paying special attention to deforma-tion, 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 mark-ings.
Lifting magnets
There are two basic types of lifting magnet on the market: permanent magnets and electro-magnets. 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 fi eld that forms between the magnet and the lifted item.
Factors affecting the size of this magnetic fi eld 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 ir-regularities must be carefully ground smooth.
Thin-walled items do not create an effective magnetic fi eld.
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 suffi cient contact
• • • • • • •
surface. In this case the lifting capacity is al-ways lower than when lifting fl at 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 ma-terials do not magnetize at all. The optimum holding capacity is attained with unalloyed low-carbon steel.
The weight of the lifted load must be propor-tioned according to the magnet manufactur-er’s instructions.
Magnets must not be used in high tempera-tures. 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. • • • • • •
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 ac-cording to the shape and quality of the load, e.g. round, angular or oval. The suction cups can be fl at, for lifting fl at 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-fl at items.
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
In addition to the required lifting capacity, the shape of the lifted load and its surface qual-ity 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 neces-sary, the danger area must be isolated.
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 suffi cient fastness and stability of the load during the lifting operation.
User instructions and a Declaration of Con-formity 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 Figure 16 Standard lifting fork
Figure 17 Lifting beams
Lifting beams
A wide range of different loading capacities, shapes and lengths of lifting beam are availa-ble. Lifting beam components and other equip-ment should also be optimally designed to suit the beam’s specifi c function.
Lifting beams or spreader beams can effec-tively 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 suffi
-the lifting fork or load during -the lifting opera-tion, the functions and the wear of the compo-nents involved must also be inspected.
cient knowledge of material strengths and struc-tural requirements. Lifting beams must have the following markings:
working load limits for different loading situ-ations
dead weight of the beam, to enable deter-mination of the lifting appliance’s payload capacity
production/serial number, name of manufac-turer
and CE marking
The following must be observed upon delivery of the lifting beam:
operating instructions, including possible re-strictions on use maintenance and in-spection instructions and assembly drawing Declaration of Con-formity • • • • • • •
LOOSE LIFTING GEAR
Lifting lugs
Lifting lug dimensions
The dimensioning of lifting lugs takes into ac-count the loads exerted on them. For example, the force exerted on the sling leg is also ex-erted 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 ca-pacity and possible restrictions on use must be specifi ed 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
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.
Figure 18 Welded lifting lug
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 restric-tions on use must be specifi ed in the operating instructions provided upon delivery.
Figure 19 Lifting eye bolt
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.
The safest models are those marked with working load limits set within suffi cient safety margins in all loading directions. The lug eye should also be able to swivel freely after fasten-ing, so the screw itself is protected from loosen-ing or over-tightenloosen-ing 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 capac-ity and possible restrictions on use must be specifi ed in the operating instructions provided upon delivery.
Always fully tighten the shackle pin before lifting. Fixed joints and attachments that
can-Figure 21 Shackles
not be continuously monitored must be fi tted with e.g. a cotter to prevent the pin from open-ing. Loading of the shackles should be perpen-dicular to the pin.
Inspection
Visually check that the pin thread is intact and that the shackle is free of fracture or deforma-tion.
Lifting accessories custom-built for individual use
Lifting accessories that are capable of meet-ing the specifi c requirements and frequently recurring lifting operations of the workplace often have to be custom-built or self-built as they are not available on the market as series products. The Machinery Decision, which came into force at the beginning of 1995, emphasises the responsibility of the manufacturer also with regard to such lifting accessories made for indi-vidual use.
Lifting accessories must be designed and made so that they are compliant with the require-ments for provision of a Declaration of Con-formity and CE marking.
Preconditions for CE marking
Risk factors concerning the lifting accessory and the lifting operation must be known and a risk assessment must be performed.
Risk factors must be eliminated through safe-ty design or safesafe-ty devices and clear warning given of remaining hazards.
Essential health and safety requirements con-cerning the lifting accessory must be clari-fi ed.
The lifting accessory must be designed and manufactured to comply with safety require-ments.
Operating instructions must be drawn up and necessary markings made.
A Technical File with drawings and strength calculations must be compiled and the nec-essary tests performed.
• • • • • •
Regulations and instructions
Occupational Safety and Health Act (No. 738/2002, (OSH Act))
The OSH Act sets out the general regulations concerning occupational safety.
Government Decision on the safety of machinery, so-called Machinery Decision (1314/1994, as amended)
This government decision contains the proce-dures and essential health and safety require-ments concerning the bringing of lifting acces-sories onto the market.
The decision lays down the obligations for the manufacturer, importer and seller.
Government Decision on the procurement, safe use and inspection of workplace machinery and other equipment, so-called Work Equipment Decision (856/1998, as amended)
This government decision specifi es the require-ments concerning machinery and equipment used at the workplace and lays down the obli-gations for the employer.
SFS Handbook 79, Lifting accessories
Finnish Standards Association manual contain-ing offi cial regulations, standards, instructions for the selection, use and storage of lifting ac-cessories and inspection and rejection criteria.
Appendix
Appendix
LIFTING ACCESSORY INSPECTION REPORT No.
NAME OF LIFTING ACCESSORY: __________________________________________________________
DEPARTMENT AND PRECISE LOCATION:___________________________________________________
MANUFACTURER / SELLER________________________________________________________________
PURPOSE OF USE:_______________________________________________________________________
WORKING LOAD LIMIT: CE MARKING Y N
SERIAL NUMBER: _______________________________________________________________________
INSPECTION INTERVAL:__________________________________________________________________
INSPECTED BY DATE FAULT(S) OBSERVED
COMMISSIONING Y N ANNUAL INSPECTION Y N ANNUAL INSPECTION Y N ANNUAL INSPECTION Y N ANNUAL INSPECTION Y N ANNUAL INSPECTION Y N ANNUAL INSPECTION Y N PARTS LIST PHOTOGRAPH DRAWING TECHNICAL DESCRIPTION 0° kg 45° kg 60° kg SERIAL NUMBER INSPECTION INTERVAL
Hand signals
General hand signals
START both arms outstretched horizontally to the side, Attention palms facing forward
Start of signal
STOP right hand raised, palm facing forward Halt/Pause
End of movement
END hands clasped at chest height of action
Vertical movements
LIFT right hand raised with palm forward,
circle slowly
LOWER right hand down with palm facing backward,
circle slowly
VERTICAL hands indicate actual distance
Horizontal movements
MOVE FORWARD both arms bent and palms facing upwards, repeated slow movement of hands and forearms towards the body in beckoning motion
MOVE both arms bent with palms facing down, BACKWARDS repeated slow movement of hands and forearms
away from the body
TO THE RIGHT signaller’s right arm extended horizontally with of the signaller palm downwards, slow small movements of arm
to the right of the signaller
TO THE LEFT signaller’s left arm extended horizontally with of the signaller palm downwards, slow small movements of arm
to the left of the signaller
HORIZONTAL hands indicate actual distance DISTANCE
Danger
DANGER both arms raised, palms facing forward Emergency stop
QUICKLY signals performed faster
