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Occupational Safety and Health Guides and Instructions 12
Lifting Accessories
Safety
OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION
Tampere 2007
ISBN 978-952-479-064-2
ISSN 1456-3614
Multiprint Oy, Tampere 2007
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 ................................................................................................................... 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
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
APPENDIX 2 Hand signals ................................................................... 30
4
Lifting Accessories • Safety
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
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 1995. 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 1995.
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
6
Lifting Accessories • Safety
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
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
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.
8
Lifting Accessories • Safety
• 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.
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
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
Straight
lift
Choked
lift
Double-leg sling
Straight
lift
Choked
lift
Multi-leg sling
Straight
lift
Sling angle factors used in the calculation of working load limits
10
Lifting Accessories • Safety
Choked
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 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
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
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
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 818-4 compliant slings contain the information shown in Figure 7.
Figure 7
Chain sling marking plate
1.
2.
3.
4.
5.
Working load limit
Nominal chain diameter
Number of sling legs
Sling angle marking
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
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:
• 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.
A chain sling must be taken out of use if:
• Damage caused by weld splash is perceived.
• The sling’s working load limit for different
load situations is not clearly marked on the
sling.
• 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
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
✔ Rusting and 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.
✔ Deformation
Inspection and rejection criteria
for wire rope slings
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.
The sling must be rejected if it contains deformation caused by kinks, bird caging, crushing,
core failure or knots.
✔ Heat damage
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.
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.
Wire rope sling inspections are usually based on
the following rejection criteria:
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.
✔ 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.
16
Lifting Accessories • Safety
✔ Damage of sling eye fittings and
attachments
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
Polyamide
=
=
Polypropylene =
blue label
green label
brown label
Resistant to weak acids, but damaged by alkalis.
Resistant to alkalis, but weakened even by weak
acids. Weakens upon wetting.
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
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
WLL
Choked lift
Basket lift
Basket lift
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
WLL
18
Choked lift
0,8 WLL
Lifting Accessories • Safety
Basket lift
2 WLL
Basket lift
1,4 WLL
1 WLL
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
A lifting belt must be taken out of use if:
• The sling contains a knot.
• The working load limit marking is not clearly
visible.
• The outer coating is broken to the extent
that the inside is visible.
• The belt has been overloaded.
• The belt contains a knot.
• The outer coating shows signs that a welding
spark, lathe chip or equivalent has damaged
the load-bearing yarns.
• The belt has extensive abrasion damage or is
generally worn and dirty.
• The sling cover 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.
• Damage to the load-bearing yarn has been
caused by chemicals, heat or moisture.
• 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 inside of the sling is damaged.
20
Lifting Accessories • Safety
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.
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.
2.
3.
4.
5.
6.
7.
8.
Body
Lifting eye
Cam segment
Safety latch
Spring
Cam segment shaft
Lifting eye shaft
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
• 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.
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
Figure 13 Lifting tongs
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.
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.
• 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
• 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
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)
b)
c)
d)
e)
24
piston
cylinder
sealing ring
vacuum chamber
valve
Lifting Accessories • Safety
f)
g)
h)
i)
reverser
torque rod
chain
rubber diaphragm
j)
k)
l)
m)
pressure chamber
alarm whistle
dust cover
bleed valve
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
the 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
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 suffi-
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
Figure 17 Lifting beams
Lifting Accessories • Safety 25
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.
Figure 19
Lifting eye bolt
26
Lifting Accessories • Safety
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 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
Lifting accessories custom-built for individual use
Lifting accessories that are capable of meeting the specific 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 individual use.
Lifting accessories must be designed and made
so that they are compliant with the requirements for provision of a Declaration of Conformity 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 safety design or safety devices and clear warning
given of remaining hazards.
• Essential health and safety requirements concerning the lifting accessory must be clarified.
• The lifting accessory must be designed and
manufactured to comply with safety requirements.
• Operating instructions must be drawn up
and necessary markings made.
• A Technical File with drawings and strength
calculations must be compiled and the necessary 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 procedures and essential health and safety requirements concerning the bringing of lifting accessories onto the market.
The decision lays down the obligations for the
manufacturer, importer and seller.
28
Lifting Accessories • Safety
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 specifies the requirements concerning machinery and equipment
used at the workplace and lays down the obligations for the employer.
SFS Handbook 79, Lifting accessories
Finnish Standards Association manual containing official regulations, standards, instructions
for the selection, use and storage of lifting accessories and inspection and rejection criteria.
Appendix
LIFTING ACCESSORY INSPECTION REPORT
No.
DEPARTMENT AND PRECISE LOCATION:___________________________________________________
MANUFACTURER / SELLER________________________________________________________________
PURPOSE OF USE:_______________________________________________________________________
WORKING LOAD LIMIT:
CE MARKING Y
N
SERIAL NUMBER: _______________________________________________________________________
INSPECTION INTERVAL:__________________________________________________________________
0°
kg
45°
PARTS LIST
kg
60°
PHOTOGRAPH
kg
DRAWING
SERIAL NUMBER
TECHNICAL DESCRIPTION
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
Lifting Accessories • Safety 29
Appendix
NAME OF LIFTING ACCESSORY: __________________________________________________________
Hand signals
General hand signals
START
Attention
Start of signal
both arms outstretched horizontally to the side,
palms facing forward
STOP
Halt/Pause
End of movement
right hand raised, palm facing forward
END
of action
hands clasped at chest height
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
DISTANCE
30
Lifting Accessories • Safety
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
BACKWARDS
both arms bent with palms facing down,
repeated slow movement of hands and forearms
away from the body
TO THE RIGHT
of the signaller
signaller’s right arm extended horizontally with
palm downwards, slow small movements of arm
to the right of the signaller
TO THE LEFT
of the signaller
signaller’s left arm extended horizontally with
palm downwards, slow small movements of arm
to the left of the signaller
HORIZONTAL
DISTANCE
hands indicate actual distance
Danger
DANGER
Emergency stop
both arms raised, palms facing forward
QUICKLY
signals performed faster
SLOWLY
signals performed slower
Lifting Accessories • Safety 31