During any lifting operation, either from a supply vessel to the installation or from within the installation or plant itself, there is a potential risk when objects are being lifted for a dropped object accident to occur.
Some of the cases wherein large objects may be dropped during lifting operations are:
- Construction, onshore, inshore or offshore, where large objects may be lifted overhydrocarbon equipment or piping and elevated structures holding hydrocarbonequipment / piping;
- Offshore installation, where large integrated decks or topsides modules may be liftedinto place by crane barges;
- Unloading containers and drilling equipment from supply boats and back-loading wasteskipsetc using the platform cranes;
- Transferring drill pipes, casing, conductors etc. from the pipe rack to the derrick andinto the well and back using the derrick draw-works;
- Changing out BOPs and Xmas trees during drilling, completion and work over activitiesusing the derrick draw-works;
- Rigging up derricks for drilling or work over activities on wellhead platforms, using thecrane from a drilling tender;
- Replacing machinery or valves for breakdown maintenance;
- Routine movements of loads around the platform using the platform cranes;
- Mechanical failure of lifting components, boom lines or slings;
- Failure of crane systems (e.g. electrical, hydraulic, pneumatic, braking system etc.);
- Structural failures (e.g. Pad eyes, crane pedestal);
- Use of non-certified lifting equipment;
- Inappropriate/ Inadequate procedures;
- Inadequate communication with crane operator during operations;
- High winds and/or supply vessel motions increasing the likelihood of accidents duringsupply boat offload and loading operations;
- Human error.
If the loads are accidentally dropped, the impacts may include:
- Injuries or fatalities among personnel underneath. These are normally covered underthe Occupational Risk in the QRA studies;
- Damage to equipment containing hydrocarbons, either on the platform or on the seabed near it. This may result in hydrocarbon leaks or, in extreme cases, blowouts. Therisks of this may be used to decide whether equipment needs to be isolated anddepressurized.
- Damage to the platform structure as a whole. This is particularly important forbuoyant structures, which may sink after being punctured by dropped objects.
Subsea pipelines or facilities need protection from hazards due to dropped objects whichmay fall from a platform, crane or drilling vessel. The dropped objects are a potentialhazard where the lifting activity is frequent, especially near the platform crane or in ashipping corridor with heavy traffic. These objects dropped onto a non-buried subseapipeline may cause indentation, crack, rupture or even crushing of the pipeline. It istherefore important to analyze the effect of such potential during the design of subseapipelines or facilities.
A Dropped Object & Swinging Load Analysis table shall be prepared for all identified hazards.