2. WEBBING SLING
(LIFFTING BELT/DUPLEX STROPS)
INDEX
-INTRODUCTION
-ROUND-WEEBING SLING
-COLOUR CODE FOR WEBBING SLINGS
-MARKINGS-TAG
-SLING TAG
-SLING CERTIFICATE
-SLINGS MATERIAL
-TYPES WEBBING SLINGS
-PACKING-PROTECTIVE
-CHART
-INSPECTION
-STORAGE/HOUSKEPPING
-SAFE USE OF ROUND/ WEBBING SLING
-OPERATING PRACTICES
3. INTRODUCTION
FLAT and ROUND- WEBBING SLING
Learn the basic of webbing sling, including the nomenclature, how it is constructed, and how
diameter and lay measurements are made.
How to choose the right webbing sling for your needs, how to extend sling service life, the
importance inspection, and how to properly store and handle webbing sling.
• Colour coded to identify WLL
• Can be manufactured using various materials eg.
Polyester
Nylon
Polypropylene
Kevlar
• Usually polyester (resists acids…damaged by alkalis)
• The webbing is produced in various widths .May be single double (simplex, duplex ) or triple
thickness. Ultimate strength and flexibility is governed by the number of layers of webbing
stitched together.
• May have “d” links attached or other end fittings attached
• 7:1 safety factor
4. ROUND- WEBBING SLING
Round slings consist of an unspun hank of polyester protected by a sheath or cover.
Due to the construction of a round sling, the load bearing element of the sling is
contained within the core.
The length of a round sling is measured at its circumference.
Provided that a round sling outer sheath or cover is in good condition -
no cuts, tears or friction burns
It can be reasonably assumed that the inner core is undamaged and
the sling is satisfactory for use.
Roundslings are almost always used like this:-
WLL reduced by 20% in choke hitch.
E.g. 2t WLL for vertical use
SWL reduced to 1.6t in this hitch.
5. COLOUR CODE FOR WEBBING SLINGS
Purple
1 stripe = 1Te SWL
Green
2 stripes = 2Te SWL
Yellow
3 stripes = 3Te SWL
Grey
4 stripes = 4Te SWL
*Number of black stripes indicates SWL.
(The colour is depend on the manufacture)
6. MARKINGS-TAG
Markings or code to
Shows ;-
Name or trademark of manufacturer
SAFE WORKING LOAD
Rated capacities for the type of hitch
Type of material
Identification number
LABEL COLOURS CODE
Green - Polyamide (Nylon) Alkali Resistant
Blue – Polyester Acid Resistant
Red/Brown – Polypropylene Resists Acid &
Alkalis damaged by solvents.
7. MARKINGS-TAG
ROUND SLINGS
Stripes show WLL for straight lift Sleeves provide protection on
e.g. 3 stripes = 3t sharp edged loads
Label gives more detailed information for WLL of
sling in different configurations
9. SLING -CERTIFICATE
Employers should hold the sling Certificate of
Conformity and where produced a Test
Certificate.
- Not just because the law so requires it -
but because it may be vital evidence in the
event of a failure of that equipment while in
service.
The certificate is documentary evidence of the
legal SWL of the sling.
10. SLINGS MATERIAL
SUBSTANCE ORGANIC
SOLVENTS
Net rope ACIDS ALKALIS (XYLENE, TOLUENE, TRIC,
PETROL, WHITE SPIRIT)
OILS
material ETC.
Susceptible to Susceptible to
Natural fibres Very susceptible Very susceptible to
attack- becomes attack
(Manilla & Sisal) to attack attack
embrittled
Susceptible to *Highly resistant to *Highly resistant to
Nylon *Highly resistant
attack attack attack
*Virtually
Polyester *Highly resistant Susceptible to attack
*Virtually unaffected unaffected
(Terylene) to attack
Susceptible to
*Highly resistant *Highly resistant to
Polyethylene attack, particularly if *Not affected
to attack attack
solvent is hot.
Attacked by some
*Highly resistant *Highly resistant to solvents *Not affected
Polypropylene
to attack attack e.g. Xylene and
Toulene
*May be suitable under the above mentioned conditions
16. TYPES WEBBING SLINGS
Choke hitch they must be
downrated by 20% when
used in choke hitch.
Basket hitch the WLL is twice
the vertical WLL.
Manufacturers supply charts
to indicate the considerable
variation in WLL which web
slings are subject
17. PACKING-PROTECTIVE
FLAT WEB SLINGS
• When using web slings extreme care should be taken to
prevent damage to the sling due to sharp edges on loads.
On supported loads the requirement to use packing is more
pronounced than with chain.
• Protective sleeves are available from suppliers which will
reduce the damage from loads with sharp abrasive edges.
E.g. Secutex
Packing on sharp
edges
21. INSPECTION
ABRASION
Localised abrasions is the result of movement of the sling over sharp edges,
this will significantly reduce the strength of the sling and justify removal from
Service.
FRICTION BURNS
A webbing sling that has been 'heated' will display hard, brittle, shiny
patches at the points where the high temperatures occurred and fused the
fibres together.
Damage usually occurs across the whole width of the sling and can be
detected by folding the sling during inspection. These hard patches are sling
weak points and are sufficient evidence to withdraw the slings from service.
Friction is the most common cause of 'heat' damage to webbing slings.
Ensure that a sling under tension is not allowed to 'skid' along load
surfaces.
Ensure that the sling is not subjected to 'point' loading such as pulling onto
a sharp corner. This produces very high pressure at the 'point' and can result
in heat fusion in the sling material.
22. INSPECTION
CUTS
Cuts in webbing slings usually result from contact with unprotected
sharp edges.
Cut damage is similar to that of „friction burns‟ except that the cut may
be clean, or matted and soft in appearance.
Inspect for cut damage in the same way as for friction burns.
Any cuts in the edge of the webbing will significantly reduce sling
strength and justify removal from service.
WEAR
Damage from wear arises only in local areas of the sling. It is caused by:
Dragging along the ground / deck.
The „bight‟ being made in the same place for too many lifts.
Wear damage from a scuffed surface will appear in patches. If scuffing
is severe whole threads may be broken.
CHAFFING
The degree of chaffing will vary. Even minor chaffing will result in some
loss of strength. Substantial chaffing, especially when it is localised, will be
justification for removal from service
23. INSPECTION
• Web slings should be examined along Sewing thread abrasion
their length for surface chafe, cuts in the
webbing, cuts or chafe damage to the
selvedges and any damage to the
stitching, eyes or end fittings.
• The effect of chafe on the surface is
variable. Any substantial
chafe, particularly localised, should be
viewed critically.
• Local abrasion, as distinct from general
wear may be caused by the sling
passing over sharp edges and will result
in a serious loss of strength.
• Heat damage may show as hard spots
and could be generated
byfriction, particularly at the bight when
choke hitch is used.
Abrasive Damage
24. INSPECTION
CUT
BROKEN THREAD S
Load bearing core Cuts, particularly at the selvedge
will result in a serious loss of
strength.
Outer cover
A sling so affected should be taken
out
of service immediately.
CUTS IN THE OUTER COVER
26. INSPECTION
CHEMICAL ATTACK
• Chemical attack is
indicated by local
weakening or softening
of the material in the
webbing so that surface
fibres can be rubbed
off, as a powder in
extreme cases.
• Chemical
attack/contamination
may show as
discolouration and is a
clear indication of
damage to the sling.
32. SAFE USE OF WEBBING SLING
Webbing slings should not be used for general lifts.
Use only under strict control whenever delicate, fragile, or specialist
lifts are required.
So Consider:
Will the sling damage the load?
Will the load damage the sling?
Is it hot?
Are there chemicals about?
Do you need adjustment?
How will the sling be Attached?
What does the load weigh?
33. SAFE USE OF ROUND/WEBBING SLING
SUMMARY – DO’S
• Stand back & “size up” the task
• Check lifting points are strong enough for the job.
• Obtain the weight of the load and check the SWL of the accessories.
• Select the correct accessory i.e. length, construction, strength & suitability.
• Check the C/G of the load
• Inspect the condition of the accessories- before use- check for: chafe/cuts/seam damage
• Observe the mode factor, ensure that the sling is of adequate strength-certificate
• Check the loads are slung correctly.
• Stand clear of the load
• Take the strain before lifting the load.
• Check accessory and lifting point attachments on suspended loads.
• Give clear & unambiguous signals/instructions to the crane operator.
• Stand where you can be seen by the crane operator when giving signals.
• Use a tag line to control long/awkward loads being lifted
• Avoid shock loading.
• Protect a webbing sling when passing it round a surface might cause damage to the fabric.
• On supported loads use packing where sharp edges are present.
• Ensure that lifting hooks or devices have smooth edges that will not damage the eyes of the
slings
• If slings are to be used in chemically abnormal atmospheres or in constant high temperatures
then seek confirmation of advice before used (A nylon (polyamide) sling can lose up to 15%
of its SWL when wet.)
34. SAFE USE OF ROUND/WEBBING SLING
SUMMARY DON’TS
• Drag accessories along the ground – carry them or use mechanical aids.
• Drag accessories from underneath a load it could pull the load over and damage
the gear – use bearers
• Pull the sling from under the load if the load is resting on the sling.
• Use unauthorised lifting accessories, always ensure they have test certificates and
as appropriate, a 6 monthly, the SWL is not known - marked
• Guess the weight of the load.
• Shorten any accessory by twisting or knotting.
• Ride on the load or in the accessories.
• Walk/work underneath any load.
• Leave accessories lying around on the ground – pick them up.
• Leave damaged or condemned accessories where they could be used by others.
• Place hands or feet near the bight of any accessory.
• Use a sling with a load without unprotected sharp edges
• Permit the opening of the soft eye in excess of 120 degrees
• Use a sling with a damage eye, has damage outer sheath (round), any damage
• Allow the eye of a webbing sung to be opened by more than 20º
• Use choked lift without protecting sling eye (allow angle of choke to form naturally)
• Lift when the sling is twisted
35. OPERATING PRACTICES
• Keep the included angle as small as possible.
• Keep the eye opening angle within 200 by using shackles – if not the
eye of the sling could be burst open.
Large included angle
Sharp edged load
Sling will be cut here
46. OPERATING PRACTICES
Answer:
Always use a shackle – do not attach the sling to the main hook
• When using web slings
care should be exercised
when connecting the upper
ends to a crane hook – the
eye opening angle should
not exceed 200
• Shackles should be used to
connect the upper legs to
prevent destruction of the
sling(s).
• If web slings have to be
joined together then
shackles should be used –
they must never be joined
together by tying knots in
them.