Recommended Guideline for Proof Test
Procedures for
Wire Rope Slings
Version I: April 2011
a publication from
®
®
AWRF
Associated Wire Rope Fabricators
Disclaimer for
AWRF Recommended Guideline for Proof Test Procedures for Slings
Part II: Wire Rope Slings and Wire Rope
Associated Wire Rope Fabricators (AWRF) makes no warranties, express or implied,
regarding the Recommended Guideline for Proof Test Procedures for Wire Rope Slings.
AWRF does not warrant, guarantee, or make any representations regarding the use or
the results of the use of this Guideline in terms of its accuracy, reliability, current status or
otherwise. The entire risk as to the results of the use of the Guideline is assumed by the
user. In no event shall AWRF, its directors, officers, members, employees, or agents be
liable for any actual, direct, indirect, consequential, punitive or incidental damages
(including but not limited to damages for loss of business profits, business interruptions
and loss of business information) arising out of the use, misuse, non-use or inability to
use this Guideline.
AWRF-Associated Wire Rope Fabricators
P.O. Box 748
Walled Lake, MI 48390-0748
U.S.A.
Phone: 1.800.444.2973
Phone International: ++1.248.994.7753
Fax: 1.800.666.2973
Fax International: ++1.248.994.7754
e-mail: [email protected]
www.awrf.org
Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
AWRF
Associated Wire Rope Fabricators
Recommended Practices and Guideline
Recommended Guideline for Test Procedures for SLINGS
Part II: Wire Rope Slings and Wire Rope
1. Introduction:
In any sling shop, one of the most important jobs that you can be asked to do is to proof test slings or
components.
The AWRF has prepared this guideline to assist you in selecting the appropriate testing methods and loads
for wire rope slings.
The recommendations defined in this document are generally based on ASME B30.9 SLINGS.
The AWRF has also prepared a Test Bed Safety Guide which explains safe testing practices when operating
proof test equipment. You are highly encouraged to read and understand this Safety Guide before operating
any proof test equipment for your own protection as well as those around you.
Version I: September, 2007
a publication from
Read and follow the safety recommendation in this guideline
2. Proof Testing Defined:
Proof testing is a quality control test where a load is applied to a sling. For wire rope slings this is usually
twice the working load limit or rated load. This is done to assure that each and every part of that sling is
more than capable of performing at the working load limit.
3. Proof Test Requirements:
Safety standards for wire rope slings, such as the Occupational Health and Safety Organization (OSHA)
1910.184 and the American Society for Mechanical Engineers (ASME) B30.9-2 on “Slings” do not require
that flemish eye wire rope slings be proof tested prior to the sling being put into service. Other types, like
loop back type slings, swaged socket slings, spelter sockets slings do require to be proof tested.
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®
®
Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
Performance specifications, such as the American Society for Testing and Materials (ASTM) A 931-96
‘Standard Test Methods for Tension Testing of Wire Rope and Strand’ provide a basic test method guideline.
Proof testing of wire rope slings is an important part of verifying a quality product. You should check with
your supervisor or employer as to your company’s testing policy on wire rope slings. You will find a
complete reference list of applicable standards at back of this booklet.
Along similar lines, all repairs to a wire rope sling need to be proof tested prior to being returned to service.
It is a good practice to proof test the entire repaired wire rope sling. Note that repaired slings must be
marked with date, and your employers name or trademark.
Table 1
Minimum Proof Test Load (lbs) for mechanical spliced Slings
(1)
For slings having hand tucked, swaged or poured socket terminations and multiple part slings consult ASME B 30.9 or the
sling manufacturer.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
4. Proof Test Loads:
The proof test load applied to each part of a wire rope sling depends on:
1) Wire rope size
2) Wire rope grade and construction
3) Number of attached legs
4) Type of splice and type of end fitting.
Rapid proof loading of wire rope slings is allowed, provided a “shock load” or “impact” condition is avoided.
The proof test load should be applied for a minimum of 5 seconds.
When conducting ‘breaking strength tests’ rapid loading well beyond the proof load of up to 80% of MBL is
allowed, provided a “shock load” or “impact” condition is avoided.
Standard Slings
Wire rope slings are generally made from EIPS grade wire rope. Check with your employer as to what grade
your slings are made of.
The proof test loads for slings made from standard EIPS and EEIPS wire rope are shown in Table 1.
Non-Standard Slings
Due to their intended specific use, some non-standard slings require non-standard components. Often
these components will have a lower working load limit than the wire rope to which they are being attached.
In cases like this the working load limit and proof test load are based on the lowest rated part of the sling.
Generally, the proof test load requirement is 2 times the lowest rated load of any sling component.
However, hand spliced slings must not be proof loaded beyond 1.25 times the rated load.
Hand spliced slings are proof tested to
only 1.25 times of the rated load.
Hook up the entire sling, including the end
attachments.
After you proof tested a hand spliced sling
to 1.25 times of the rated load you must now
test the end attachments separately to 2
times the rated sling load. Do NOT load the
spliced sling when testing the fitting !
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
5. Getting Started
Make sure you follow all of your employer’s safety and operation procedures when operating proof test
equipment.
Refer to the AWRF Test Bed Safety Guide or ask your supervisor if you have any questions or concerns.
Make sure the fixtures being used with the wire rope sling are rated for the proof test load to be applied.
Use properly sized
and rated test
attachments
Use appropriate clothing, safety
boots, safety goggles, hard hat, and
gloves to protect your hands.
Inspecting the rope for defects
Inspection of all fittings
Inspecting splice and sleeve
The slings should be reasonably clean and should be visually inspected for any defects prior to proof
testing.
The slings should be loaded into the test bed without any twists or kinks.
The fixtures should be aligned with the sling so that straight line tension is applied to the sling. Off-center
loading can cause incorrect loading of the sling.
Do not attach a wire rope sling leg to a swivel.
Slings can be heavy. Ask for assistance or use material handling equipment before moving heavy slings.
After the proof test is complete, it is a important to visually inspect the sling for any signs of damage that
may have occurred.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
Recommended Guideline for Proof Testing of Wire Rope Slings
6.1 Single Leg Slings
Apply the required proof test load to the entire sling, with the load points being the loop eye, thimble eye or
upper end fitting and the loop eye, thimble eye or lower end fitting.
Load to be applied is: 2 x vertical capacity of single leg [2xWLL of slingle leg]
Straight pull of a single leg wire rope sling
Use test pins which are at least 2 times
larger than the wire rope size.
6.1.1
Slings that are longer than the test equipment are allowed to be tested in a basket hitch provided the
recommended test pin sizes are used.
For test pin sizes refer to section 7
Longer slings can be tested in a basket hitch provided
the proof test load is doubled.
Use a pin diameter around the rope BODY of at least 25 times the rope size (D/d of 25:1)
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
6.2. Endless or Grommet Slings
Apply the required proof test load using pin sizes following Section 7.4.
Load to be applied is: 2 x vertical capacity of the sling [2 x WLL of slingle leg]
Place swaged sleeves or splices centered between the test pins .
Place swaged sleeves or splices centered between
the test pins.
Make sure you use large enough thimbles or test pins to prevent
damage to the sling. See page 16 for details.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
6.3 Two Leg Slings
6.3.1 Each Leg
Apply the required proof test load to each leg of the sling, with the load points being the master link and the
lower loop eye, thimble eye or end fitting.
Load to be applied is: 2 x vertical capacity of single leg [2 x WLL of single leg]
Alternately, if the sling fits into the test equipment, the proof test for each leg may be applied to both legs at
the same time (Note: The master link would be in the middle).
If your test bed is long enough you can test
the sling spread out.
With this test method the master
link sits in the middle.
6.3.2 Master Link
Apply the required proof test load to the master link. The load shall be applied to the master link by itself.
For master link test pin sizes refer to section 7.6
Load to be applied is: 4 x vertical capacity of single leg [4 x WLL of single leg]
6.3.3 Entire Sling (Two Leg Sling)
The proof test requirements of 6.3.1 and 6.3.2 can be met by applying the required proof test load to the
entire sling providing the following load conditions. The load points would be the master link and the lower
loop eye, thimble eye or end fitting provided that there is a load equalizing method to assure that the proof
test load is equalized between both legs and that there is less than a 10˚ included angle between the legs.
For master link test pin sizes refer to section 7.6
Load to be applied is: 4 x vertical capacity of single leg [ 4 x WLL of slingle leg]
Using this method the master link is proof
tested at the same time.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
6.4 Three-leg slings
6.4.1 Each leg
Apply the required proof test load to each leg of the sling, with the load points being the master link and the
lower loop eye, thimble eye or end fitting.
( 2 x vertical capacity of single leg [ 2 x WLL of single leg].
The master link is attached to the test pin and
each leg is tested separately, one-by-one.
Alternately, if the sling will fit the test equipment, a proof test for 2 legs can be applied at the same time in
the manner described in section 6.3.1 but the test has to include the proof test on each leg, at least once.
Note: It is permissible to test one leg twice, if required.
In this picture 2 legs are tested
together. The 3rd leg will be tested
after that.
The 3rd leg hangs free while
2 legs are being tested.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
6.4.2 2-legs at the same time
The proof test requirements of 6.4.1 can be met by applying the required proof test load of the sling
providing the following load conditions. The load points would be the master link and the lower loop eye,
thimble eye or end fitting of 2 legs provided there is a load equalizing method to assure that the proof test
load is equalized between both legs and that there is less than a 10˚ included angle between the legs.
The third leg can be tested with the same method although one of the 3 legs would be proof tested twice;
this is permissible.
For master link test pin sizes refer to section 7.6
Load to be applied is : 4 x vertical capacity of single leg [ 4 x WLL of single leg]
2 legs are tested out of 3 at the same time. This method does NOT test the
master link at the same time !
6.4.3 Master Link
Apply the required proof test load to the master link. The load shall be applied to the master link itself. For
master link test pin sizes refer to section 7.6
Load to be applied is: 6 x vertical capacity of single leg [6 x WLL of single leg]
The master link is tested separately
while the 3 legs hang loose.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
6.5 Four-leg slings
6.5.1 Each Leg
Apply the required proof test load to each leg of the sling, with the load points being the master link and the
lower loop eye, thimble eye or end fitting.
Load to be applied is: 2 x vertical capacity of single leg [ 2 x WLL of single leg].
The master link is attached to the test pin and
each leg is tested separately, one-by-one.
6.5.2 2-legs at the same time
The proof test requirements of 6.5.1 can be met by applying the required proof test load to 2-legs of the
sling at a time providing the following load conditions. The load points would be the master link and the
lower loop eye, thimble eye or end fitting of 2 legs provided that there is a load equalizing method to assure
that the proof test load is equalized between both legs and that there is less than a 10˚ included angle
between the legs.
This test has to be repeated twice to test all 4 legs.
Load to be applied is: 4 x vertical capacity of single leg [4 x WLL of single leg]
In this picture 2 legs are tested together. The 2 legs which
are slack in this picture will be tested next.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
6.5.3 4-legs at the same time
The proof test requirements of 6.5.1 can be met by applying the required proof test load to 4-legs of the
sling providing the following load conditions. The load points would be the lower loop eyes, thimble eyes or
end fittings of all legs (the master being in the center of the sling) provided that there is a load equalizing
method to assure that the proof test load is equalized between each pair of legs and that there is less than
a 10˚ included angle between the legs.
Load to be applied is: 4 x vertical capacity of single leg [4 x WLL of single leg]
This method requires 2 sets of
equalizing beams or plates.
The master link is in the middle but will NOT be proof tested at the
same time. You need a much greater load; see below.
6.5.4 Master Link
Apply the required proof test load to the master link. The load shall be applied to the master link itself. For
master link test pin sizes refer to section 7.6.
Load to be applied is: 8 x vertical capacity of single leg [8 x WLL of single leg].
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
6.6 After the proof test
After you have finished the proof test of the sling you need to, again, inspect the sling and all components
for any damage which resulted from the test procedure. Inspect the rope, links and all end fittings for
damages; e.g. slipped fittings, stretched links, stretched hooks, loose sleeves, bent pins, stuck or hard to
turn shackle bolts, individual wire breaks, elongated or stretched sling legs etc.
Keep in mind that at this point the sling must be fit for use.
Carefully inspect the sling for any
damages which could have been the result
of the proof load. Pay particular attention
to slipped fittings, stretched links,
stretched hooks, loose sleeves, bent pins,
stuck or hard to turn shackle bolts,
individual wire breaks, elongated or
stretched sling legs or any other
deformation.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
7. Proof Test Fixtures
The fixtures used for proof testing wire rope slings will vary on the type of sling and the types of end fittings
on the sling. Improper fixtures can cause some damage to a sling. Therefore, care should be taken to
make sure that the proper fixtures are being used.
Version I: September, 2007
a publication from
Do not use damaged pins and fixtures.
Fixtures and operation should comply with the AWRF “Practices and Guidelines for the Operation of Test
Machines” . Test bed fixtures and attachments should be marked to indicate the maximum load for which
they are to be used.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
Care should be taken to select fixtures that do not cause point loading, localized damage or deformation to
the components and slings being proof tested. Below are the recommended guidelines:
7.1 Loop test pin sizes
To assure that the bearing portion of the loop preserves as much of the natural shape of the wire rope used,
the minimum test pin size must be no less than equal to 2 x the rope diameter but not larger than the natural
width of the eye. If a used wire rope sling is to be proof tested and the eyes have stretched to be straight,
the maximum pin size must be no less than 20% of the stretched loop length.
It is permissible to proof test new or used wire rope slings using a hook as a fixture as long as the bearing
portion of the hook complies with the above.
Use test pins which are at least 2 times
larger than the wire rope size.
Proof testing an eye&eye sling with a
too small pin will result in permanent
damage to the loop.
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But, test pin sizes must NOT be larger than the
natural width of the eye. In this example severe
damage to the sling and sleeve will occur.
Instead, use a solid thimble which ensures that
the loop is not damaged PLUS, the thimble will not
get damaged either.
Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
7.2 Thimble test pin sizes
When proof testing slings with a thimble eye, the test pin shall be of a size to prevent the thimble from
significantly deforming at the proof load. Usually, the thimble test pin shall fit the inside of the thimble but
allow for enough clearance to prevent the pin from binding upon removal of the sling from the test machine.
If hardware is connected with a thimble to the wire rope slings such hardware may not be of sufficient size to
prevent the thimble, at proof load, from stretching and collapsing. In such cases a stronger thimble or a
thimble with a welded-in gusset shall be used.
‘Standard’ wire rope thimbles are usually not capable to withstand proof loads without distortion.
Using too small of a pin will cause the thimble to
significantly deform; even if you use the correct
shackle capacity for sling. Don’t forget that you
proof test to double the rated load.
The result of a too small pin; the thimble
significantly deforms during the proof
test. Not all thimbles are made equal and
some will NOT be able to sustain such
loads.
In this picture a 2” pin of a 25 ton shackle fits the thimble of a 3/4” wire rope
sling. This prevents the thimble from significantly deforming at proof load.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
7.3 Slings tested in a basket configuration
If slings are too long for a given test bed length they are allowed to be tested in a ‘basket’ configuration. For
6-strand rope slings the test pin used to create the basket configuration shall be a minimum of 25 x the rope
diameter. For all other sling constructions consult the sling manufacturer.
This test method may result in a slight bend in the rope body.
Use a pin diameter around the rope BODY of at least 25 times the rope size (D/d of 25:1)
7.4 Grommet- or Endless wire rope slings test pin sizes
As per the “Wire Rope Sling Users Manual”, mechanically spliced and hand tucked grommets made as
strand or cable laid types have a minimum pin diameter requirement of 5 x the grommet body diameter.
Consult the grommet manufacturer as to the recommended test pin size.
To proof test most grommet slings you need to load them over a pin or
thimble which has 5 times the diameter of the grommet size (D/d 5:1).
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
7.5 Hardware pin or shackle pin bore sizes
Follow the hardware manufacturer’s recommendation for the proper proof test connection method for the
applicable sling fitting.
7.6 Master Link test pin sizes
Suitably large pins or fixtures should be used to prevent localized point contact damage to master links.
Ideally, the radius of the pin should match the inside radius of the master link, and ASTM A 952 allows 60%
fixture width. From a practical standpoint, the minimum pin diameter should be at least 40% of the inside
width of the master link if not otherwise specified by the link manufacturer.
In any event: the selected test pin size shall assure that the proof testing procedure does not result in
localized damage or distortion of the link.
To proof test the master link of a multiple leg sling is probably the hardest part of your routine.
Whatever you do make sure that do not distort the ring and that the testing pins do not leave
permanent impression marks on the inside of the master link.
Other than that: Stay safe !
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
8. Wire Rope Destruction Tests
Destruction tests on wire rope are generally performed on new rope to confirm a manufacturers breaking
strength to meet a customer specific certification standard or requirement.
Breaking strength tests on used wire rope are, by themselves, of limited value. Remember that the
remaining ‘working life’ or ‘residual fatigue life’ of a crane wire rope can NOT be gauged by a simple
breaking strength test of a rope done ‘in straight line’. Even if one would attempt a test method in a basket
configuration over a stationary wire rope sheave such a test would NOT replicate the actual working
condition of a crane rope and the attained residual rope breaking strength result could lead to a potentially
dangerous assumption on residual working (fatigue) life of a crane rope.
For the purpose of this publication the following standards have been considered:
> ASTM A931-06 (2002)
> ISO 3108:1974
> EN 12385-1 (2002)
> API 9A (2004) and ISO 10425:2003
All of the Testing sections of the above standards are very similar and by following the guidelines below you
will have adhered to all of them.
8.1. End fittings
Poured sockets are considered the most efficient termination method. Compression fittings, such as swaged
sockets or loop terminations, will result in a reduced actual breaking load of the rope. However, such end
fittings are acceptable provided the test results meets specifications.
Compression grip or wedge grip (but not wedge sockets) methods are acceptable as they allow for a quick
set up. Confirm with the manufacturer if their grips are suitable for destruction tests.
Follow the manufacture’s recommendations for installation of the rope fittings.
8.2 Sample length
A typical sample length is 60” (1524 mm) or a minimum of
: 30 x d for stranded rope
: 50 x d for spiral ropes (e.g. bridge strand)
: 118” (3000 mm) for ropes >2-3/8” (60 mm)
whichever is the LONGER length as per above.
Note that longer samples (> 100 x d) usually break nearer to the rope’s center as the effect of potential rope
distortion at the end fittings is better equalized in a longer sample.
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Recommended Guideline for Proof Test Procedures for
Wire Rope Slings and Wire Rope
Version I: April 2011
®
8.3 Test speed
80% of the rope’s expected breaking strength can be applied rapidly. None of the standards mention any
specific speed values. ASTM A931-96 sets a maximum rate of stretch at .032”/minute x sample length in
inches. Check current edition.
Above the 80% value the increase in load shall be NO MORE (not faster) than 0.5% of minimum breaking
force per second (20% / 0.5% = 40 seconds)
Alternatively, the time it takes to complete the breaking strength test procedure exceeding the 80% value
shall be a minimum of 60 seconds. By adhering to this number you have complied to all of the above
mentioned standards.
Longer time duration tests are allowed.
8.4 Completion of test
The test is completed when no further increase of force can be applied to the sample. The test may already
be finished without breaking the rope when the minimum breaking force of the rope has been reached or
exceeded.
Standards Referenc e Listing
ASME B 30.9, Chapter 2
ASTM A 931 - 96 (Reapproved 2002)
ISO 3108:1974
EN 12385-1 (2002)
API 9A (2004) and ISO 10425:2003
Wire Rope Sling Users Manual, Third Edition
ASTM A 952 - 02
Wire­Rope­Slings:­Selection,­Use,­and­Maintenance
Standard­Testing­Methods­for­Tension­Testing­of­
Wire­Rope­and­Strand
Steel­Wire­Rope­for­general­Purposes
Determination­of­actual­breaking­load
Steel­Wire­Ropes­-­Safety­part­1:­General­Requirements
Steel­Wire­Ropes­for­the­Petroleum­and­Natural­Gas­Industry
Minimum­Requirements­and­Terms­of­Acceptance
140­pages­about­Wire­Rope­Slings­including­Load­Tables
Standard­Specification­for­Forged­Grade­80­and­grade­100
Steel­Lifting­Components­and­Welded­Attachments­links.
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Printed­in­Canada,­2011