Pumps and monitoring equipment are usually housed in a covered area away 

 from the effects of weather. This allows these vital pieces of equipment to 

 be overhauled at any time without regard to outside conditions. Pumps and 

 compressors are usually connected in pairs for each pipeline. Both members of 

 a pair will be operated at the same time, unless one is undergoing an overhaul. 

 One pump or compressor is capable of doing the required work; however, if two 

 are placed on line, the pipeline can continue to run when one piece of equip- 

 ment is out of service. There is often a third, back-up, pump or compressor 

 that can be placed into service if both primary pumps fail. Diversion valves 

 and pipes are built into the site for the back-up pump (Davis and Cyrus, 

 1947). 



The pumps, compressors, and other equipment are partially powered by 

 electricity, therefore, electric lines are nearly always present. Power for 

 compressors and pumps may be electric, though they are more often fueled by 

 natural gas or diesel fuel. Consequently, gas lines or fuel tanks may have to 

 be placed at the site. 



Pump stations may simply be boosters along the pipeline; they may be 

 points of collection for several sources of natural gas or oil; or they may be 

 points of division and dispersal of petroleum to several customers. Conse- 

 quently, communications systems are "^ery important to pipeline operations. ■ 

 Telephone communications are standard to nearly every pump station. In addi- 

 tion, radio and microwave systems are often used to communicate, operate 

 equipment remotely, and monitor equipment. Tall microwave towers are often 

 found at pump stations to relay communications signals along the pipeline 

 route. 



Pump stations are occasionally placed in marsh areas or on platforms 

 above water. The same equipment is found at these stations, and the construc- 

 tion methods will be similar to those used to build marsh and platform produc- 

 tion sites. 



Testing pipelines. Pipelines and the intermediate pump stations are 

 tested before a pipeline company accepts them for operation. Testing procedure 

 is determined by the pipeline company and is usually done in sections (Petro- 

 leum Extension Service, 1972). This is because testing is often done hydro- 

 statically, and the volume of water required to test a long pipeline all at 

 one time might be prohibitively expensive. In addition, testing of shorter 

 sections allows quicker isolation and identification of leaks (detected by 

 pressure drops). 



The inside of the pipe is cleaned by scraper passage, and a fluid or gas 

 is introduced into the pipe. Then the pipe is pressurized. There is a regimen 

 of pressures that must be maintained for selected time periods to test the 

 pipeline. Usually the pressures are considerably higher than the operation 

 pressure will be. The entire testing sequence may take several days and 



120 



