Figure 37 Jacket foundation crew access system and work platform, courtesy of RWE.
Function
The crew access system and work platform enable operations service personnel to gain safe access to the turbine platform and allows loading, unloading and storage of equipment.
Who supplies them
The crew access system and work platform are usually supplied as part of the transition piece, see suppliers of transition pieces [B.2.3].
In practice, the steelwork for the crew access system and work platform may be subcontracted to a smaller steelwork supplier.
Key facts
Adverse weather conditions can limit access to turbines and delay essential maintenance, leading to revenue loss. Currently, most crew transfer vessels (CTV) are able to offload crews in wave heights of 2 m. Some turbines have systems to enable helicopters to drop crew but if used routinely, this is an expensive solution with health and safety concerns.
The simplest and cheapest option for turbines located close to shore is to use a small CTV. In this case, the vessel will press up against the boat landing, which consists of a pair of strong parallel vertical beams (known as “bumper bars”) mounted onto the transition piece. This allows the service personnel to step across to a ladder located between and slightly behind the boat landing, clip into the fall arrest system, and hence gain access to the main work platform and the turbine. Intermediate rest platforms may also be included between the boat landing and platform access. This method of access is limited to significant wave heights (Hs) of approximately 1.5-2.0 m. There are a number of systems which extend the range of sea conditions under which it is safe for personnel to transfer across to the access ladder.
Service personnel may also arrive on a larger service operation vessel (SOV) equipped with a motion compensated gangway. In this case, they can step straight from the gangway onto the main work platform. Motion compensated gangways allow turbine access with Hs of up to approximately 3-4 m.
The main work platform is typically located about 25 m above MSL in order to be clear of splashes during storm surges, even at high tide. It is sized to allow the storage of small ISO containers, which are frequently used to transfer parts and equipment to offshore wind turbines. They could also be used to store a generator, which is commonly needed before the turbine is connected to the grid.
The main work platform is surrounded by guardrails and will have lights and textured non-slip decking to provide a safe working environment.
What’s in it
- Steel framework
- Decking
- Guardrails