For over 25 years of
providing equipment solutions for UK companies, there is one trend that
is seen more often than any other. Something goes wrong with a particular piece
of equipment, and instead of retiring it, the owner keeps using it until the
problem reaches critical levels. That can happen through a failed inspection.
Sometimes, it is due to a close call. And, sometimes, it is much worse!
Based on our experience, one thing about the decision-making regarding lifting equipment retirement is that it often comes too late. That is the combination of habits, unwillingness to spend the money and, most importantly, confusion around when to keep a piece of equipment and when to retire it. This blog post is aimed at solving that problem.
Firstly, it should be
clarified that not every single defect renders a piece of equipment useless.
Some defects are easy to repair without compromising its integrity, such as
safety latches on load hooks that have broken; damaged supply cables on electrical
components or worn chain links.
Secondly, depending on
the type of equipment some failed components can be replaced with new ones, to
restore it to near original operating condition. For example electrical
contactors in electric hoists or new load chain on any chain hoist.
Secondly, what cannot be repaired is compromised structural integrity. The point is that if the load-bearing element of the equipment is damaged, deformed or just degraded, it cannot be restored to the rated capacity even by the most diligent maintenance practices. This is where the choice should be made. And the way to do it is quite simple: if a piece of equipment cannot be restored to its original capacity by a competent person, retire it.
While chains are
rather durable, they can become compromised in some ways that are not easily
noticeable. Stretched chain is the major indicator of that. Chain that is
stretched beyond its specified tolerance has been overloaded and compromised
structurally even if it appears to be still intact. In case a chain is found to
have an excess elongation comparing to its original specifications, it is time
to replace it.
Also pay attention to
wear spots in the chain links, which reduce its diameter. Since the
load-bearing capacity of a chain depends on its diameter, in case the wear is
more than 10% of the diameter, the chain should be replaced.
The presence of bent,
twisted or cracked links is another reason to retire a chain. These things show
that the chain has undergone some forces and conditions that it wasn't designed
for. Cracked links cannot be repaired, so there is nothing else to do but to
replace the chain.
Corrosion is one more defect to be treated with extra care. While surface rust is an easy-to-remove problem, the pitted corrosion of the links that goes below the surface is a much more serious problem since the structural integrity of the links is questionable. Our advice is to retire a chain in that case.
Another common issue
that we encounter in our work is the inappropriate treatment of webbing slings.
They are cheaper than many other types of lifting equipment, so it seems like
it is cheaper to ignore their degradation and keep using them for much longer
than it is supposed to be.
Cut and abrasion are
the most obvious reasons for the retirement. Every cut of a webbing sling that
penetrates the load-bearing fibres reduces its rated capacity. Therefore, if
there is even one cut that breaks those fibres, it is time to retire a sling.
Heat and chemical
damage also reduce the structural integrity of the sling although it may not be
easily seen. Discolouration, brittleness and stiffness of the webbing material
are signs of that. In case the lifting slings are used in the environments with chemicals
and high temperatures, they need a more frequent checkup than usual.
An illegible or missing label also means the need for retirement according to LOLER. It is impossible to use a sling without knowing its rated capacity. There is no alternative to that.
As for wire rope,
sometimes it provides some visible signs of damage, however sometimes issues
are hidden internally. Broken wires are the primary sign. If the wire rope is
approaching its end of the lifetime, its wires may start to break. There are
some rules in the standards for wire ropes of how many broken wires are
permitted; typically 4% wire filament breaks are acceptable before becoming
detrimental to the rope's safety. Always refer to the EN safety code EN12385 —
there should be a specific length of the wire rope — six or thirty times the
wire diameter. So, if the number of broken wires is more than the required, the
wire rope is to be retired.
If the wire rope is kinked, it should be retired immediately. Kinking means the permanent deformation of the wire rope that compromises the arrangement of the wires inside of the rope. Corrosion, crushing, bird caging are also the indicators for retirement of the wire rope. According to our experience, the wire ropes that are stored and used in wet or corrosive conditions can become damaged inside while the outer layer stays intact.
Hooks, like many other
pieces of equipment, are frequently forgotten when it comes to retirement. It
may be because they are rather robust and substantial. The truth is that the
hooks can get deformed during their operation and that should be taken into consideration.
The key parameter to look at is the throat opening. In case a hook becomes
opened and its width increases even slightly; it means that the hook has been
overloaded and the structure of the hook is changed. That is why it is
impossible to rely on its rated capacity anymore. Retirement is the only way to
go here.
Twisting of the hook shank, the cracks in the hook body and the damage to the safety latch also mean retirement. The hook without the latch should be retired right away regardless of any other defects.
Shackles are easy to
assess but they can get damaged and go unnoticed by their owners. The
indication of overloading is any deformation of the bow: bending, distortion,
stretching. In that case, the retirement is necessary. In our experience, there
is no reason to keep deformed shackles in service since they are relatively
cheap.
It is important to
make sure that the pin of the shackle corresponds to the shackle and is the
original or a manufacturer-approved one. In many cases, it happens that
multiple pins can get mixed up from their correct saddle. In that case, the
rated capacity of the shackle cannot be assured.
The corrosion of shackles used in marine and outdoor environment should be controlled carefully. In case there is the pitted corrosion of the load-bearing part of the bow, it should be retired.
Even though powered
and manual hoists are more complex pieces of equipment than the accessories,
the same approach to their retirement should be used. The first and the main
criterion is the failure of the brake to hold the suspended load. If a brake
stops working and cannot keep the load suspended, the equipment is to be
retired right away. No other actions can be taken until the equipment is
inspected and the problem is fixed.
Other indicators that should cause concern are the damaged or cracked housing, chains jumping and skipping in the mechanism and unusual noise when the equipment is under load. In our experience, the hoists that have fallen, even once, from some moderate height should be inspected before the further usage. Internal damage is not visible externally.
According to LOLER,
the lifting equipment is to be subjected to thorough examination regularly —
every six months in case of lifting accessories and the equipment used to lift
people and every twelve months in other cases. Thorough examination of the equipment
is done by the competent person and allows condemning the equipment that is
found unserviceable regardless of its age and condition.
Our experience shows that this is the most valuable part of the thorough examination since it removes the responsibility for the decision from the person who has financial interest in keeping the equipment in service. The equipment found to create an existing or imminent risk of serious personal injury during a thorough examination should be reported to the enforcing authority. The condemned equipment cannot be used anymore and there is no appeal procedure involving the use of the equipment to find out whether there are other opinions on the matter.
One of the misconceptions that should be corrected here is that lifting equipment does not have a certain period of service life as it happens with the car tyres, for example. There are many factors that can influence the equipment's ability to operate properly and those are not its age but the condition, the maintenance and storage methods. According to our experience, the companies that retire equipment in time are those that pay more attention to the condition than the age of it. Pre-use inspections and thorough examinations with subsequent actions done in time are the factors that decide on the serviceability of the equipment.
It is obvious that replacing a sling or a shackle is cheap while keeping it in service after it has been found compromised can lead to the dropped load, serious injury, HSE investigation and prosecution. According to our experience, the companies that refuse replacing the worn-out equipment because of the costs do not take this equation into account. The cost of replacement is known and finite while the cost of an accident is not.
Retire the equipment
if the compromised load-bearing structure cannot be repaired by the competent
person to the manufacturer's standard. Retire it if there are visible defects,
like chain elongation, broken wires, throat opening, cuts on the webbing and
others that exceed the acceptable level. Retire it if it is condemned by the
competent person in the course of thorough examination. Repaired components can
be if they are easily remediable by a competent person.
If you need some help
in determining whether your equipment should be replaced, our team will be glad
to help you. In our 25-year experience, we have seen too many worn-out pieces
of lifting equipment to provide reasonable advice. For consultation on the condition of
the equipment and its replacement, please call us at 01384 76961.
