After years of collaboration, the Heavy Lift Exchange Forum, a working group initiated by classification body DNV, has issued the “Guidance on Stability of Lifts” – a detailed operational guideline for stable and safe heavy lift operations.
Developed as a collaborative effort by industry leaders, including BBC Chartering, BigLift Shipping B.V., Heerema Marine Contractors, Jumbo Maritime, SAL Engineering and United Heavy Lift GmbH & Co. KG., this new guidance empowers engineers and operators to make heavy lifts safer based on decades of operational experience.
The guidance dives into the key considerations and calculations to help ensure these hazardous operations are performed safely to reduce the risk of loss to life, property and the environment.
The guideline offers a systematic, flowchart-based approach to planning and evaluating the stability of rigging arrangements. It reflects real-world workflows used by participating companies and provides detailed methods to safer heavy lifting operations.
“The paper Guidance on Stability of Lifts plugs a gap among the many guidance documents available for operations in the maritime sphere,” says Karsten Behrens, Managing Director of SAL Engineering GmbH. “It enables readers to assess the stability of particular lifting arrangements by using the provided methods and data. This puts them in the position to achieve a ‘stable lift’, which is one that remains in a balanced condition, within a safe margin, when subjected to predefined disturbing factors.”
The paper explains currently available calculation methods, along with relevant explanations, guidance for assumptions on loads and factors, and background information. The core of the paper is a flow chart for assessing the lifting stability of a rigging arrangement, which also reflects the common workflows of the participating project partners. Checkpoints and information blocks in the chart enable users to review the rigging plan they have created, to assess its suitability, and to create a framework of boundary conditions.
In an easy-to-follow systematic approach, the guidance then works through details clarifying steps from the flow chart. To assist the process, the guidance makes a comprehensive comparison of different methods to assess the stability of lifts. These methods are the Virtual CoG concept; the Kaps method, which is widely used in the maritime industry; the Nikitin method; and standard and extensive versions of numerical computer simulation methods. The applicability of these methods for various purposes is discussed.
The guidance paper explains several disturbing factors, together with relevant mathematical equations for calculating their impacts. It presents this material in a way that allows these factors to be incorporated into the calculations for rigging stability assessment. Read the full guidance here. Source: DNV Image: BigLift Shipping
· Comparing and applying key stability assessment methods like Virtual CoG, Kaps and numerical computer simulations in combination with;
· factors like wind force, crane movement, CoG shift and friction at lifting points for precise planning.
