POWERBASE^® Gas & hydrocarbon barriers

Chemical Resistant Classes at New School

A former pallet works in Saddleworth is the home for a new secondary school. Saddleworth School is being rebuilt under the Government’s Priority School Building Programme (PSBP). The new location for the school is the mining town of Diggle, 2km away from the current school. Interestingly, the new 22-acre site has had several industrial uses and records dating back to 1854 show that the site was initially used as a mill; demolished in the early 1900’s, the mill made way for a loom works. More buildings were constructed until the land was taken over by W.H. Shaw Pallet Works, reputedly one the largest factories of its type in Europe. The factory assisted in the war effort during WWI when the buildings were used for munitions, and again in WWII, when the factory-made parts for Russian submarines.

To make way for the new larger capacity school all the industrial buildings have been cleared, except for a gothic clock tower that forms part of an original administrative building that is grade II listed.

The site investigation report assessed the ground gas regime as a Characteristic Situation 2, requiring gas protection measures to mitigate the risk. However, a further ground report inspection by our groundwork’s specialist Paul Harrison, showed historical ground contamination, mainly hydrocarbon by-products. These hydrocarbons were outside of the scope of standard test codes, and as such no membranes were tested to the specific contaminants found at the site. Using ITP’s unique hydrocarbon modelling software, Paul put to test the specific contaminants vapour permeation when using our advanced barrier membranes. The results enabled the ground consultancy to confidently specify Powerbase VOC.

Speaking about the analysis that Paul carried out, Bryan Woodcock, SpS Substructure Protection, said “We have a great working relationship with ITP, they operate as an extension to the SpS team, and their full range of products fulfil almost every type of installation requirement we have, easy to install at a reasonable cost.

Special consideration should be given to sites contaminated by hydrocarbons or VOCs as the mobile compounds migrate with relative ease through unsuitable membrane materials. Aluminium laminates are superb gas barriers, but these materials will delaminate when exposed to hydrocarbon vapour/VOCs and the aluminium layer is susceptible to oxidation due to moisture penetrating exposed edges.

Powerbase VOC, was supplied to SpS Substructure Protection, the installers at the site. A specially engineered multilayer composite barrier membrane, Powerbase VOC is made from protective polymeric layers on both side of a chemical resistant hydrocarbon barrier inner core, offering exceptional resistance to hydrocarbons and VOCs (volatile organic compounds); it complies with Ciria C748, BS8485, NHBC Chapter 4.1 and NHBC Red Gas Protection Measures.