Surface drainage at gas plant


TO process gas and liquid hydrocarbon reserves, a new on-shore plant is being built on a 540,000m² site located to the east of the established Sullom Voe oil terminal on Shetland.

The engineering, procurement, supply, construction and commissioning contract for the plant itself was awarded to Petrofac’s Offshore Engineering & Operations unit in October 2010. Morrison Construction was then awarded a contract by Petrofac in June 2011 to carry out site infrastructure works including underground and surface water drainage facilities, roadways and buildings. The plant site is on a steep slope and required extensive earthworks. This together with the plant’s location and harsh weather conditions meant the surface water drainage system employed would have to be robust and very efficient at controlling surface water runoff. All collected surface water had to be channelled into a separator and tested for contamination before being released into the sea.
Calculating the hydraulic performance needed, Morrison Construction were looking for a channel system available in at least three sizes to drain the site’s roads and service areas. After dialogue with Hauraton UK technical support staff, the company’s FASERFIX® SUPER 300, 400 and 500 channels were specified with Class D400 ductile iron slotted gratings. The grating specification chosen featured parallel rows of 20mm wide slots, each half metre grating being secured to the channel with the company’s patented SIDE-LOCK system and eight high tensile bolts.