Fuel Supply

Upgrading the Secondary Containment at the Senoko Oil Depot
in Singapore, Steve Flynn

Several options are available to engineers in the design of petrochemical containment to achieve the required level of permeability. These include concrete, underlying (or imported) compacted clay, or membranes. Clay has traditionally been the barrier used at the older facilities, installed prior to the construction of the tanks and bunds around them. Some sites are located on good clay and tests have proved they meet regulation and need no further attention. Other sites, however, have been found to not meet
requirements and need upgrading. The options to bring these bund floors up to regulation primarily involve the use of concrete or the use of a membrane as the importation and compaction of clay into existing sites is impractical.  The membrane option is divided between geomembranes (plastic type sheets) and bentonite membranes known as Geosynthetic Clay Liners (GCLs).  One site currently using a GCL to provide the secondary containment solution is located in Singapore. The site contains 12 tanks holding a variety of fuels including AVCAT and Marine Diesel. The site is of pre-World War II construction, with earth bunds constructed in silt and heavily weathered Bukit Timah Granite with compacted floors and earth banks of the same make-up. The site although in Singapore comes under the COMAH regulations as it is run by a UK military organization and therefore follows the UK compliance requirements. The upgrade of the site involves the installation of a prehydrated sodium bentonite membrane, Rawmat HDB, to the floors and slopes of the bunds to ensure the facility meets the impermeability requirements for COMAH compliance.

Read the full article in the Institution of Royal Engineers journal April 2020