Accommodation/helideck in the forward position has an advantage of upwind of major hazards and fire or smoke in an emergency.
The positioning of the helideck should take account of the wind environment around the FPSO, particularly turbulence, vertical component of wind velocity and hot gas plumes from flares or turbine exhausts, both at the helideck and on the approaches.
The height of the helideck and the air gap between it and the living quarters below should ensure a clean a flow of air.
Helideck layout should allow for either parking of a broken-down helicopter or a platform crane should be able to have helideck coverage and capacity to permit helicopter removal.