February 18th, 2010 - OSB scores highly in the BRE Global’s Green Guide
The environmental impact of a building project has never been higher on the industry’s agenda. The threat of climate change and the consequent need to reduce carbon emissions has changed the way we think about building design and materials.

The correct choice of building materials is fundamental to achieving a sustainable, low-carbon built environment. To help specifiers and designers make an informed choice, leading research body, the Building Research Establishment (BRE) has developed its highly influential Green Guide to Specification.
 

By Mike Buick, Brand Manager, Norbord Europe

The Green Guide provides an authoritative assessment of the environmental impacts of various building elements. It currently contains more than 1500 specifications used in various types of building.

Easy to use and based on sound, proven numerical data, the Green Guide contributes to BRE’s Environmental Assessment Method (BREEAM), the most widely accepted environmental rating scheme for buildings in the UK.

The Green Guide works on a similar basis to the energy rating of domestic refrigerators and other appliances, but with the ratings applied to an element rather than an individual material, with the score ranging from A+ (lowest environmental impact) to E (highest environmental impact).

The Green Guide arranges materials and components on a building element basis so that specifiers can compare and select from comparable approaches as they compile their specification. The elements covered are external walls, internal walls and partitions, separating walls, roofs, ground floors, upper floors, separating floors, floor finishes, windows, insulation and landscaping.

Building elements containing a considerable proportion of wood tend to score well thanks to the environmental profile of the material.

As a renewable resource, wood is also a genuinely sustainable building product when grown in properly managed forests. Where sustainable forest management can be demonstrated by a certification scheme, then this may be eligible for Responsible Sourcing credits within BREEAM’s Materials section.

Specifiers using the Green Guide will also notice that building elements incorporating oriented strand board, of which Norbord’s Sterling OSB is the UK’s leading brand, consistently score well for environmental impact.

OSB is made from forest thinnings – small-diameter logs from trees thinned out of plantations to allow space for the best specimens to grow to maturity. Instead of being burned or chipped for biomass fuel or mulch, the fibre from these thinnings is mixed with special resins and wax and bonded under heat and pressure to produce a strong, high quality board product.

Norbord’s Sterling OSB is produced in a factory that uses process residues – the waste material that cannot be converted into a panel product - as biomass fuel to provide some of the energy required for the manufacturing process. By 2002, Norbord had reached its target of the panel’s sector Climate Change Levy Agreement set in 2001, to reduce its greenhouse gas emissions by 12.5% by 2008, and continues to reduce its consumption of fossil fuels.

OSB’s environmental profile is such that elements incorporating the material consistently out-score those same elements in which plywood is used instead.

Although good quality birch ply from European forests is a high quality, sustainable material, it is both more expensive than OSB and has a higher environmental impact, in part due to the fact that it is made from premium quality large logs.

Evidence of this is given in the Green Guide to specification where, for example, a ground floor structure comprising OSB/3 decking on timber joists with insulation over 100mm 50% GGBS oversite concrete scores A+ in the Green Guide while the same structure with EN636-2 plywood decking scores A.

This difference is consistent throughout the Green Guide: where a design incorporating OSB, the score will be better in most instances than if the specifier had chosen plywood.