then barged offshore to the "lay-barge", which simultaneously joins the 

 sections and lays the pipe in a virtually continuous operation. 



A potential pipe-coating yard site must be flat or nearly so. 

 Additionally, the land must be firm enough to support the weight of 

 concrete-coated pipe, and must have good drainage. 



Pipe-coating yards vary considerably in size and complexity. On the 

 one hand, a small, temporary, single-season facility on a 30-acre site may 

 rent equipment and lease land to meet an immediate offshore field demand 

 for 50 miles of pipe or less. On the other hand, a large permanent 

 operation occupying a 75 to 200 acre site may install the most modern 

 coating equipment and environmental control systems to meet a demand for 

 200 to 400 miles of pipe per pipe-laying season. A season is primarily 

 defined by favorable sea conditions in which the offshore lay-barge can 

 operate. For a Gulf of Mexico yard, a season is about 8 months. 

 Activity at a yard also is related to such non-seasonal factors as 

 progress in OCS field development, and changing production rates that 

 affect pipe demand and delivery schedules and thus cause fluctuations in 

 employment and work loads. 



A pipe-coating yard is relatively simple. A permanent yard can be 

 constructed and operational in as few as 6 months (3 months for a 

 temporary yard). Pipe-coating yard components typically include a large 

 open area for pipe storage, rail and marine shipping terminals, separate 

 pipe cleaning and pipe-coating structures, warehouse and repair and 

 maintenance buildings, and an administrative office. 



A yard requires a relatively small labor force. During pipe-laying 

 periods a typical yard is active, noisy, and dusty from the frequent 

 handling of large pipe sections and the operations involved with the pipe- 

 coating processes. 



The pipe is first scraped, brushed, and either sand- or shot-blasted 

 to remove rust and to provide a clean surface. The next step is the 

 application of an anti-corrosive (asphaltic-aggregate) mastic coating 

 to a preheated pipe, usually in an indoor facility. The pipe is then 

 cooled by spraying the inside with water. Then a whitewash mixture of 

 hydrated lime is applied to the fresh mastic coating. The pipe sections 

 are stored unstacked on the ground until the coat has hardened. The 

 weighting coat of concrete and iron ore is then applied to the pipe while 

 it is simultaneously wrapped with reinforcing galvanized wire mesh. A 

 final curing mixture also is applied. After curing (4 to 24 days) the 

 sections are stacked on a prepared sand bed. 



At the end of the one-month coating period, the finished pipe is 

 loaded on supply barges and towed to the lay-barge. A 150-foot barge 

 of 60-foot beam is capable of hauling roughly one-half to one mile of 



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