Industrial lifting equipment: selection criteria for hook blocks
May 6, 2021 1:47:49 PM
Selecting the right lifting equipment for our project will always depend on multiple factors related to operating conditions as well as the sector of application. If we want an effective solution in terms of safety and durability, we also need to consider the manufacturer’s technical knowledge and expertise, implemented quality controls and strict compliance with applicable standards.
Considerations according to work requirements
Hook block manufacturing can be standard or tailor-made, and the design will vary according to the requirements of each project. Therefore, to select the most appropriate solution we should consider some essential factors:
- The working group: as specified in FEM, DIN or ISO standards. This is an essential factor since it will guarantee the lifting systems safety and durability in the required service conditions.
- Dimensioning and load capacity: factors related to the job at hand must be taken into account, including load spectrum, lifting capacity, speeds and service temperature.
- Uses: onshore, offshore or undersea.
- Manual or motorised handling.
- Application and related standards: in general, compliance with requirements set forth in FEM / DIN standards is essential. Depending on the sector where we operate, the product may also need to meet with specific regulations.
- Quality Documentation.
Criteria to be considered according to the sector of activity
Hook blocks need to meet specific criteria according to each application environment. The main aspects to be considered are:
- Construction and Travelling Crane: Specific lifting systems are required for this application. Working groups with reduced operating times, M3 - M4, therefore, there is higher design flexibility and a wide range of solutions that can be obtained to adapt to the specific needs of each project.
- Oil & Gas and Offshore: Operating times are highly variable, M3 - M6 working groups. These sectors are particularly demanding in terms of quality and controls carried out by external inspection bodies. Since they are required to work in vessels, oil rigs or submersible drilling platforms, hook blocks must meet watertightness and pressure resistance requirements, and should be protected with specific coatings.
- Ports and Shipyards: Working groups are variable (M3 - M6) but should withstand high speeds and, to provide an appropriate response, solutions must be highly resistant.
- Mining and Industry: Hook blocks may be standard or specially designed to suit the requirements of each project. In these sectors, lifting equipment is frequently used in overhead travelling cranes. Operating times are high with M3 - M8 working groups, with particularly adverse work environments, extreme temperatures, polluted atmospheres, etc. As a result, the equipment should be fitted with the appropriate guards and lubricated accordingly.
Hoists should meet the following requirements to increase safety and maximise the service life of mechanical components:
- Safety latch to prevent slings from slipping off the hook.
- Specific hooks for each application.
- Pulley guard system, to avoid cable leaving using pulley or rod guards.
- Anti-rotation systems to keep hooks in place.
In addition, manufacturers should guarantee the quality of materials through NDTs.
It is also worth considering the use of cables with bigger metal cross-sections and 200 and 220 kg/mm² resistances to allow reduce diameters for cables and sheaves. This is particularly indicated for heavy loads since smaller and more affordable hook blocks can be used.
Criteria for selecting a manufacturer
When selecting the most appropriate lifting system, it is important to take into account certain criteria related to the supplier. Firstly, it is advisable to opt for manufacturers with broad experience in the sector of application.
An experienced engineering team will be able to offer solutions suitable for specific loading conditions avoiding the oversize of the product. This is essential, since oversizing the hook blocks leads to an unnecessary weight gain for the lifting system, as well as price increase. This situation happens when the actual load conditions are unknown, or when the supplier is unable to offer smaller items. In both cases, the manufacturer will offer a hook block which is bigger than what is required leading to increased costs.
Furthermore, the supplier must have the necessary certifications based on each project, including also accreditations issued by external bodies. Finally, selecting suppliers with advanced technical expertise is recommended, since they can offer high quality solutions at competitive prices.