How to Determine the Service or Duty Classifications of Cranes & Hoists

Cranes and hoists duty or service classification is a bit delicate process. The reason that creates such implication is the involvement of numerous standards that further use different methods to determine duty ratings. Having said that, to make the process easier, several methods are adopted and classification complexity is reduced to a remarkable point. One most acknowledged way is equipments out for selling are rated with domestic and/or foreign standards. The regulation, however, is a discussion thing as when a crane and hoist supplier advertises the rated duty cycle; one has to give it a thought. As there is no such direct oversite available for regulating the classification system.

Like if you go or the electrical equipment, there is a specific IS document by Bureau of Indian Standards that verify and inspect the service class of equipment is available with the suppliers. So, it is recommended for purchasers to do careful scrutiny of equipments supplied by potential suppliers. The most looked point should be meeting the service and duty requirements of the purchaser. This article will help understand the classification system, the standards, and their applications on various equipment. Here, we have covered these standards for analysis

• IS
• CMAA
• HMI
• AISE
• ISO
• FEM

What does crane duty classification mean?

Crane duty classification is done as per the crane load condition and the grades of crane used. The principle of classification lies in the frequency of different cases, average load, and having the same crane life at the same level.

The crane classification helps improve the generality level of pièces de grues too. One can determine by the lifting weight of crane components that are working in the same general crane level. This reason has made the crane classification as an important basis for the crane components, crane parts, and its component design. Also, security check, scrap standard, and accident analysis is considered as the basis to determine standard. So, if we see the duty classification, scrap standard, and safety factor is different, but taking all these together help in determining the crane classification with better insight.

Before buying a crane, why it is needed to confirm the duty classification?

To determine the suitability of the cranes for your application as well as to establish the most economical choice, it becomes important to identify the duty classification of the crane types. The appropriate choice of the crane duty cycle gives you better results as durability assurance of cranes and components as rightly applicable for the usage and loads requirement. So, it is suggested to determine the overhead crane duty classification while buying.

If you see, the cranes with similar capacity and span but can have a huge difference in their prices due to their different duty classification. The high duty classification cranes has specific components and parts as electric motors, electric hoist, bearings, end carriage, and crane controls. On the other hand, in low duty classification cranes are standard ones and designed in a more economical way of having economical components. This helps in establishing the low price for the lower duty classification.

Also, while you are buying the cranes, you should take the future prospect in consideration. If you are planning a long term work or have blueprint of production expansion in future, then the production capacity will enhance. This will lead to the more number of lifts each day or more load in each lift. So, the purchase needs to be suitable for seeing your future requirements.

What are the factors that affect crane duty classification?

Selecting a suitable crane duty class for your crane is very important. It directly affects the initial investment cost in your production and also your future maintenance cost required is largely impacted. For selecting the suitable crane duty, mechanical components, crane structure, the purchaser needs to give the following details to the supplier. This helps the manufacturer to understand application needs. The following factors you should be considering while selecting the crane duty classification for your overhead crane:

• Rated Load- Average load estimation need to be lifted in a day
• Service hours- Total operation hours in a day
• Number of Lifts- Average number of lifts in an hour
• Distance- Estimated travel length of each movement

Other points that are advisable to note does not directly affect the service and duty classification of the cranes. But these are significant in crane specifying and designing.

• Speed- How much time the lifting crane takes in transferring the materials or equipment? What are the numbers of the lifts a lifting overhead crane perform in an hour?
• Maintenance requirements- What are the servicing requirements of the lifting crane? Is it required on a regular basis or a time gap is allowed? Also, how the service or repair is going to affect the downtime and production?
• Operating environment- What is the environment or production conditions where overhead bridge crane is supposed to operate?

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