With all the different rigging gears, the production and safety manager has to stay focused on inspection frequencies for the lifting equipment. The lifting equipment includes the metal mesh sling, the wire rope slings, chain slings, synthetic web slings and synthetic round slings. All of these have different inspection frequencies and sling tag requirements.
One can understand how much coordination and effort are needed to comply with the safety standards. But it becomes imperative for the industries to have qualified employees who are highly trained to deal with the alloy chain slings.
A chain sling inspection program, however, can deal with any industry compliance issue. It extends the life of the chain sling while keeping the user safe. This article will discuss the use of chain sling and its inspection.
Who performs the Chain Sling Inspection?
A designated person performs all the inspections. They are the qualified person who identifies different damages and provides the steps that one needs to take in case of those damages.
Inspection before initial use: Once you receive it from the manufacturer, you should always inspect and double-check to avoid any damage.
Inspection before daily use: A competent person should be designated to perform the daily inspection.
Periodic inspection: The periodic inspection of the chain sling should be performed by any qualified person or a professional inspector. As per the Indian Factory Safety Act, one needs to inspect the chain sling regularly every 12 months. There are some determining factors to consider while you schedule the periodic inspection frequency. These factors include
- The severity of the service condition
- Frequency of use
- Nature of the lift that is being performed
- Experience gained over the alloy chain slings' service life.
According to safety norms, there are some periodic inspection guidelines. These are:
- One should do normal service yearly
- Severe service needs to be done on a monthly to quarterly basis
- Special service requires a recommendation from the qualified person
The authorised person should decide the inspection period of the sling chain based on the frequency of use and the severity of the operating environment. It is a prevalent issue that most of the business faces related to maintaining the inspection records.
Requirement needed on the identification tag of the chain sling
Whenever you are using the chain for overhead lifting, you need to ensure that the gradation of the chain should always be composed of alloy Steel and not carbon Steel. It is mandatory that the sling should have an identification tag. If whatever you are changing does not meet these requirements, the user should refrain from using it for overhead lifting.
Alloy chains have more strength than that carbon chains. As per the safety standards, the sling chain should include
- Name of the manufacturer or trademark
- The nominal chain size
- The gradation of the chain
- The number of legs
- Type of hitches that needs to be used
- The individual identification serial number of the sling
- The length of the sling
If, in any case, the tags are illegible or missing, then the inspector should immediately remove them from the service. Furthermore, one should send it to the authorized repair facility for updated or current tagging, testing and certification.
Application that can damage the chain slings prematurely.
Certain environmental and application methods can naturally damage the parts of chain slings. Therefore, it becomes crucial that the inspector inspect the rigging gears. Often it is seen that sling abuse occurs during the application. But if you can understand what kind of application caused the failure or the premature wear of the chain, it would help you better when you inspect the slings.
As per the inspection criteria, chain damage can be categorized into five categories. These categories include:
- Nicks and gouges
- Shearing
- Localised bending
- Wear
- Stretch
For instance, in some cases, the overload causes the chain to stretch. While in other situations, the severe angles may also cause overloading in the sling. The typical angle should be 60 degrees, whereas the rated capacity can vary from 30 degrees to 45 degrees. The sling angle affects the tension on either side of the sling greatly. If the legs are further apart on the sling, then it causes more pressure.
Always measure the distance between the two hook up points. And then, you can decide the required sling length according to the measurement of the distance. For example, if you are taking the distance between the two hooks up points as three-meter, then the legs of the slings should be 3 meters long. This practice makes sure that the distance between the two hook points and the two-leg length of the sling forms an equilateral triangle.
Let's discuss the type of damages briefly in Chain Sling
1. Nicks and Gouges
You use a chain sling to pull, secure all its materials; the outer surface of the chain links can come in direct contact with foreign objects. Therefore, it can cause a lot of damage to the chain sling. As these slings are under compressive stress, therefore, reducing the potentiality can have a harmful effect.
The unique geometry of every chain link protects the chain sling from the tensile stress area. These stress areas that are on the outside of the link body save the stress against every damage. It happens with the help of the presence of corresponding links.
However, the tensile stress area can also originate on the inner part of the straight barrel. But these surfaces are somehow sheltered by the location. Gouges can also cause an increase in link stress. It can turn harmful if located in the area of tensile stress, especially when the gouges are present perpendicular to the pressure.
2. Shearing As the name suggests, Shearing is the case when the chain sling is chopped off.
3. Bending and twisting
You can constantly evaluate chains once you apply loads. Bringing the chain around the corner or edges can significantly alter the regular loading pattern. Once you bend or twist, the chain can adjust the inner link stresses. Once you see the internal link stresses, you can understand that it is a failed product. A lack of proper consideration or padding of the D/d ratio can result in bent links or twists.
If the chain bends or twists, it will invariably alter the inner link stresses. This alteration can lead to the failure of the alloy chain sling. For this very reason, all the chains containing the bent links of the twists must be removed by the company immediately. If you use proper screen protection, you can eliminate the damage to your alloy chain sling faces.
4. Wear and Corrosion
When you use the chain links, you have to handle them multiple times. With the rigorous application of handling, the chain erodes. You must inspect the sling chain for multiple defects to avoid any unsafe lifting. Sometimes it can even lead to operator injury.
Corrosion can occur at any place of the chain sling. When the chain comes in contact with water or harsh chemicals, it can start showing evidence of faster corrosion which leads to more wear. If you see that your chain has some corrosion, you must determine how severe the damage is. You can remove the general surface corrosion by oiling the chain or by cleaning it. If the pitting persists, then you must remove it from the service.
5. Chain and stretch elongation
The last and the best method to inspect alloy changeling is to go for a visual link-by-link inspection. You should also measure the reach of the chain sling from the bearing point on the lower hook to the upper bearing point that original it's on the master link. The loss of clearance or the slightest sign of bending at the juncture point can indicate collapse. It generally happens due to the stretch. Overloading is an instance that can cause the stretch to occur.
In other words, the inspector should follow some of these procedures to make sure that your chain sling will work properly. For any professional rigger, they must know how much safety is essential when one does a particular job. Working safely involves staying trained and happens to be a necessary measure while one is working. Let us check some of the ways to inspect your chain sling.
- Thorough cleaning of each sling
- Checking the identification tag legibility
- Measuring the reach of the chain sling legs
- Linking link inspection of the excessive wear
- Follow it with an examination of any deformation, degradation, or severe corrosion.
Be safe and get trained.
The market has an ongoing demand for highly qualified technicians. Since the maintenance of alloy chain sling requires an expert to supervise, one should have proper qualifications and training to understand and take care of its science.
Even if you don't have any certification regarding inspecting your alloy chain sling, you should take the above-stated precautions and regulations daily. By staying updated with regular training or rules, you can have the safest applications. To inspect your alloy chain sling for maximum safety, follow this guide, and you will have the safest application ever.
Conclusion
It would be best to always remember to designate a qualified inspector who can perform the inspection daily. Also, you must provide necessary training to the sling users before they even opt for using the sling. This practice would help them to keep updated with the proper usage of the chain sling.
Here are some of the best practices that you can follow while inspecting and using the chain sling.
- Knowing the weight of the load
- Determining the different types of hitch
- Using the appropriate style and size of the sling
- Using the practical and longest slim
- Storing the slings properly
However, these can help in preventing any damage. It would be best if you examined your slings usually every time before you use them.
