Issues regarding the design of lifting lugs for pressure vessels
Thread Content
As the title suggests: For a new project undertaken by our company, there is a batch of pressure vessels (Category 3). The design institute did not design any lifting lugs; according to the staff at the design institute, it is the construction party’s responsibility to design these lifting lugs based on the lifting plan, and the design institute is not responsible for that. In my opinion, since the lifting lugs must be welded to the equipment itself, the design institute should conduct a stress analysis before designing them; it is impossible for the construction party to carry out such an analysis. What do everyone think about this issue? The matter is currently stuck on this issue; please help come up with some ideas and find theoretical grounds to persuade the design institute!
It seems that stress analysis isn’t necessarily required for the lifting lugs; it should be sufficient to select them based on their diameter
Designers should take into account the forces acting during lifting when designing, in order to ensure the safety of the lifting lugs and the equipment; it is irresponsible for design institutes to claim otherwise.
When designing, we must consider the impact of lifting lugs on the equipment; generally, stress analysis is not necessary. The placement of lifting lugs is something that the design institute is responsible for deciding; it cannot be assigned to the lifting company.
The lugs for heavy equipment that are characterized by being high, special, and large are generally designed by lifting companies. These companies determine the lifting plan, identify the points of force application, and then design the lugs. Some established engineering companies generally do this. Lifting small equipment is relatively easy; the equipment specialists can simply select and install lifting lugs in accordance with the standards.
In earlier years, not enough attention was paid to this issue; it was only as accidents caused by lifting operations became more apparent that greater emphasis was placed on it. Nowadays, as the owner, the client requires design firms to provide lifting lugs for ordinary containers, while for larger containers, the installation company submits a plan which is then combined with the design and approved by the designers to ensure safety
Firstly, it is the responsibility of the design team to handle this properly; each piece of equipment should be designed with lifting lugs. It’s possible that adjustments to these lugs may be necessary after the lifting plan is finalized. But if, as part of equipment design, lifting is not even taken into consideration, it’s like giving someone a TV without telling them how to place it. In special cases, such as when the equipment is extremely large and it’s not possible to determine a lifting plan during the design phase, installing lifting lugs might cause unnecessary problems. In such situations, it is possible to state that the lifting lugs will be installed once the lifting plan has been finalized; however, it’s not acceptable to omit this step altogether. Secondly, regarding the solution to your problem, I suggest that the property owner engage a lifting company to prepare a lifting plan. Based on this plan, the locations for the lifting lugs can be initially determined, after which these locations can be finalized in consultation with the design institute. In any case, the design institute must be involved in the final design of the lifting lugs, even for the final approval process. After receiving payment for their design services, they have corresponding responsibilities; otherwise, it would be a waste of money.
For ordinary equipment, the design unit can be requested to provide lifting lugs on it. For large-scale equipment (including towers), it is the lifting company that is responsible for determining the location of the lifting lugs; this is not a matter of whether the design team is involved or not. Only after a lifting plan has been established can the structure, location, and quantity of the lifting lugs be determined, and it is the lifting company that forms this lifting plan.
For large-scale equipment, neither the design institute nor the installation company can carry out the design of the lifting lugs on their own; the design institute is not aware of the specific lifting methods, while ordinary installation companies do not possess the skills to carry out such design work. The most reasonable approach is for both parties to work together in coordination. Design institutes now aim to keep designs as simple as possible, which makes communication rather difficult.
After the installation team receives the drawings, they send their feedback on the lifting points back to the design institute; after communication between them, the information is passed on to the equipment manufacturer. These items are still after the port orientation diagram