This Specification defines the basic requirements for the fabrication of the primary structures of offshore installations. These will normally include but not be limited to the following:  Jacket structure including nodes, cones, braces, legs and conductor framing;  Piles and followers;  J-tubes and caissons;  Riser clamps;  Flotation tanks and buoyancy tubes;  Module support frame including nodes, cones, braces, padears;  Module framing including nodes, columns, fabricated beams and padears;  Flareboom;  Helideck - when constructed of steel;  Subsea structures such as manifold and production system support frames;  Renewable energy structures, both surface and subsea; and  Other areas designated 'primary' on the Purchaser approved drawings. The attachment by welding to primary steelwork (but not the fabrication) of items such as doubler plates, riser supports and walkways, also comes within the scope of this Specification. This Specification may also be used for the fabrication of deck mounted module framing on floating offshore structures. This Specification may also be used for modifications to existing structures, subject to the limitations imposed by the original materials and fabrication techniques. All other structural components shall be fabricated to EEMUA 197 or other document approved by the purchaser. The requirements of this Specification are necessarily of a general nature, and individual projects will normally apply short supplements to reflect any peculiarities of design or duty which affect them. Pipeline risers are not covered by this Specification