Chain lever hoists are used extensively in underwater construction activities. Their design characteristics allow for ease of transportation to site and require minimum set-up.
The IMCA said: “Unlike the chain hoist, which can only be used upright and vertical, the chain lever hoist can be used in almost any orientation. This makes it potentially a very useful tool for diver use during subsea construction activities.”
However, there has been a history of failures in the use of this equipment, both underwater and topside.
“The changes in this version reflect the experience gained by the industry using the original guidance, and it incorporates lessons learnt during investigations into lever hoist incidents over the last five years,” said IMCA technical director Jane Bugler.
She added: “The offshore environment can be particularly harsh, with its combination of temperature extremes, wind-blown dust or grit, atmosphere, silt, washing out of lubricants and general corrosion from seawater. This has prompted critical examination into the cause of these failures, with a view to establishing industry guidance on the safe application for use of chain lever hoists.”
The revised guidance features a new section on the use of chain lever hoists underwater. This includes an analysis of some of the latest incidents and then goes on to give guidance aimed at preventing, as far as possible, the types of failure that has been experienced in recent years, and goes on to provide guidance on lift planning; the use of static rigging or multiple rigging points to avoid single point failure; practical considerations during subsea lifting operations; and immersion policy, Bugler added.
A number of existing standards and specifications for chain lever hoists exist and each country will have its own legislation regarding the conducting of lifting operations. The intention of the revised guidance is not to replace any existing standards or legislation, but to supplement them by providing IMCA members with specific guidance for the safe use of chain lever hoists in the offshore subsea environment.
The guidance (IMCA D 028 Rev 1) is available for downloading from the members-only website, with additional printed copies available at £2.50 for members, or £5 for non-members (plus 20% for delivery outside Europe) online at www.imca-int.com/publications or from IMCA at 5 Lower Belgrave Street, London SW1W 0NR UK. Tel: +44 (0)20 7824 5520, fax: +44 (0)20 7824 5521, email: publications@imca-int.com.
