The International Marine Contractors Association (IMCA) has published ‘Guidance on the Manufacture and Safe Use of Cable-laid Slings and Grommets’ (IMCA M179). The guidance was prepared by a working group of experts, and is intended to provide assistance to those concerned with the use of cable-laid slings and grommets used in engineered lifts for offshore heavy lifting operations. The guidance gives advice on their construction, rating, testing, certification, examination and use.
“’Engineered lifts’ are those where the mass and centre of gravity of the lifted object is determined (i.e. calculated/measured) with extreme accuracy, “explains IMCA’s Technical Director, Richard Benzie.
“Slings can be specially manufactured or selected for this lift, and will only be used for a limited number of lifts with a clear record of each. Calculations are performed and documented (loads and geometry) to show that slings are adequate for the lift and the procedure for the lift is well documented.
“Our working group for the review and updating of this guidance document comprised the IMCA Lifting & Rigging Management Committee (LRMC); Heerema Marine Contractors; Hendrik Veder Group; KTL Offshore; Saipem; Seaway Heavy Lifting; Technip; United Offshore Services; Gebr. Henschel; Subsea 7; Usha Martin; Bridon; Wire Rope Consultancy; Franklin Offshore; and Millfield Group. We would like to thank them for their invaluable work on this important document. We look forward to feedback from users.”
IMCA M 179 was first issued in August 2005 and has been revised for a variety of reasons and in order to reflect:
- · good practice in the manufacture and safe use of cable-laid slings and grommets;
- · the fact that larger test facilities that have become available in recent years enabling the industry to perform destruction tests on cable-laid slings;
- · newer methods of eye construction;
- · alignment of the document with current codes;
- · and alterations to the calculation of calculated rope breaking load (CRBL), calculated grommet breaking load (CGBL) calculated sling breaking load (CSBL) and sling bending loss formula.