The second Line of Defence
Petrochemical storage facilities are conscious to select the best secondary containment systems, and with growing attention to the environment there is no shortage of companies to supply them
The environment is at the top of everyoneÍs agenda. Oil and related products can be a threat to the natural world when they leak, causing major environmental consequences that kill wildlife, pollute water and spoil agricultural land. It takes both great expense and time to clean up a spill, so a second layer of protection is required as a safety net.
The first layer of protection present at a terminal is known as primary containment, and includes the tanks, pipes and vessels that hold liquids and the devices fitted to them to allow them to be safely operated.
Secondary containment consists of enclosed areas known as bunds or berms, composed of concrete or earth walls, present to hold in any escaped liquids and any water or chemicals used in fire-fighting. Tertiary containment includes drains designed to limit the passage of petrochemical products offsite, and raised kerbs to prevent liquids that have breached the bunds and general area around the site. Major overfills and leaks have tested secondary containment in the last few decades, including a leak of 265 tonnes of petroleum from a Texaco tank terminal in New Jersey, US, after a tank was overfilled in January 1983. Another recent issue arose from the Buncefield petrochemical depot explosion in December 2005 in the UK. During the explosion, primary containment tanks and containers were ruptured and cracks appeared within and under bund walls. Fire water and product escaped due to damaged sealant and corner joints which opened up.
With such a lot at stake, both financially and environmentally, secondary containment is closely monitored. ïAsset owner operators have to comply with current UK legislation requiring them to demonstrate secondary containment protection is in place,Í comments David Rice, UK strategic industry manager for oil and gas at Belzona protective coatings company.
Legislation of secondary containment is becoming stricter throughout the world, as a result of greater publicity and environmental awareness. As an example of this, New YorkÍs Department of Environmental Conservation (DEC) is pushing to ensure terminal operators, storage and oil companies are compliant.
ïThe DEC has increased its workforce and is starting to do more visual inspections of secondary containment in petrochemical storage terminals,Í Ted Hobin Jnr, VP of US industrial maintenance company Maple Grove Enterprises, says.
A significant amount of work is also being undertaken to ensure terminals adhere to American Petroleum Institute (API) Standard 653: tank inspection, repair, alteration and reconstruction. API produces standards, recommended practices, specifications, codes and technical publications, reports and studies that cover each segment of the industry. The API standards programme has gone global, through active involvement with the International Organisation for Standardisation (ISO) and other international bodies.
