Last year Environmental Efficiency carried out over 400 bund integrity assessments throughout the UK and Ireland, that’s nearly 2 bunds every working day. The bunds inspected ranged from IBC sump pallets up to Upper Tier Seveso fuel storage bunds.
In Ireland, most integrity assessments were by hydrostatic testing in accordance with the EPA Guidance Document on Storage and Transfer of Materials for Scheduled Activities and BS8007: 1987 Code of practice for design of concrete structures for retaining aqueous liquids . In cases were hydrostatic testing was not safe or practical, a visual inspection is carried out by a Chartered Engineer.
In the UK, all assessments were by visual inspection to CIRIA 736:Containment systems for the prevention of pollution. This assessment procedure is significantly more rigorous than used in Ireland. In the UK, the old 25%/110% bund capacity rules has been replaced by a risk assessment procedure that takes into account a determination of the realistic loss of containment (it may be 100% of the largest tank) plus an allowance for rainfall for 24 hours before failure, during failure and 8 days after failure plus a free board of 250 mm for wave effects. In addition, where the tank contents are flammable, all joints and pipe penetrations require assessment for fire resistance.
The most common integrity failure types are poor sealing of wall and floor joints in mass concrete bunds. These sealants have a life of around 10 years (considerably less if used on floors with vehicular traffic). The second most common reason is unsealed or poorly sealed pipe penetrations through the bund wall.
Some failures would be comical if they weren’t so serious. One bunded chemical warehouse had a ground water monitoring point in the middle of the floor. This was only spotted after asking for an IBC to be moved. Fortunately, no bunds were found with holes in them to let the rain water out as in previous years.
Environmental Efficiency is an Irish based full service environmental and H&S consultancy helping companies achieve and maintain compliance with best practice. Our clients range from start-ups to global multinationals in the commercial and manufacturing sectors.
The author, Bob Sutcliffe, can be contacted at the Bray office, 01 276 1428 (00353 1 276 1428) or firstname.lastname@example.org
Source: Environmental Efficiency