Here are the requirements one should consider:
- Structural components should be fabricated from standard pipe, square tubing, shapes, and/or plate in accordance with the requirements of API RP 2A and/or API SPEC 17D as applicable.
- Tubular members should be open to sea or should have two vent holes (minimum 1/2 in.) located in the uppermost and lowermost portion of the member when mounted to allow easy flooding during installation and to prevent hydrostatic collapse.
- The vent holes should be arranged to prevent circulation of seawater within the member.
- All welds should be full penetration.
- The edges of sheared plates should be ground to remove the rolled-over edge wherever the sheared edge should be connected to another member.
Wherever the surfaces of two structural shapes are in contact with one another, a sealer bead should be placed at the edges to completely seal the contacting surfaces from the ambient environment. A mouse hole should be included where three or more planes are joined.