Platform fabrication yards 



Offshore OCS oil and gas drilling and production are conducted from plat- 

 forms that are constructed of steel or concrete. The main body, or jacket, 

 supporting the platforms is constructed almost entirely of tubular steel that 

 is fabricated onshore at a waterfront location, placed in the water and towed 

 to the installation site, and set in place on the ocean floor. Decks, drill- 

 ing rig, living quarters, and other rig components also are constructed 

 onshore and towed to an offshore site. Several types of platforms are con- 

 structed depending upon depth, sea bottom type, weather trends, the mix and 

 type of oil and gas in the find, and other factors. 



Platfonn fabrication yards are large marine facilities usually consisting 

 of fabrication shops, welding racks, pipe mills, concrete mixing plants, and 

 cement storage silos (if concrete platforms are used), and administrative 

 facil ities (Table 13). 



Table 13. Siting conditions and potential sources of pollution from platfonm 

 fabrication yards (Adapted from New England River Basins Commission 1976b). 



Categories or elements 



Economic requirements/pollutants 



Site considerations 



Land 

 Berthage 



10-324 ha (25-800 acres) 



61-122 m (200-400 ft) 

 5-15 m (15-50 ft) depth 



Water 

 Type of pollution 

 Air emissions 



10,000-100,000 gal/d 



Sand and metal dust 

 Concrete and cement dust 

 Nitrogen oxide 

 Sulfur oxide 

 Hydrocarbons 

 Organic compounds 



Wastewater contaminants 



Heavy metal s 

 Chemical s 

 Particulates 



Noise 



Up to 100 dBA on a 24-hour basis 

 (measure of the intensity of sound) 



154 



