Breeam guidance

Developed in the early 1990s, BREEAM is based on many years of construction and environmental research and validated by input from the construction and property industries, government and building regulators. There are currently 13 versions including

• Offices
• Industrial
• Retail
• Healthcare
• Prisons
• Courts
• Multi-residential
• Schools

When is a building assessed under the BREEAM scheme?

The BREEAM scheme assesses the environmental impacts arising as a result of an individual building development at two stages:

1. Design Stage - leads to an Interim BREEAM Certificate.
2. Post-Construction Stage – leads to a Final BREEAM Certificate.

A post-construction review serves to confirm the interim assessment and, importantly, confirm that the ‘as built’ performance matches that of the design stage. To achieve this it is important to maintain the specification of materials, e.g Colorcoat® pre-finished steel cladding and preserve the quality of the details to retain design standards for air-tightness and thermal performance. 

Which criteria should be considered to achieve a high BREEAM rating?

The operational energy performance of buildings and associated CO2 emissions, is the most highly weighted and challenging criteria within BREEAM. Of the energy issues assessed, Ene 1 and Ene 6 relate to the specification of the building envelope.

Ene 1 -  Reduction in CO2 emissions

Up to 15 credits are available based on the buildings CO2 index (EPC rating) taken from the Energy Performance Certificate (EPC).
Buildings envelopes incorporating Colorcoat® pre-finished steel can easily achieve good operational energy performance. Steel envelope systems minimise fabric heat losses by providing:

• Good levels of thermal insulation (low u-values; down to 0.16 W/m2K for roofs and 0.2 W/m2K for walls)
• Good air-tightness and good detailing of interfaces within steel envelopes can achieve air-leakage rates of less than 3 m3/m2/h.

Ene 6 - Building fabric performance & avoidance of air infiltration

Compliance with this criterion includes a number of measures relating both to the building fabric and specific design measures. Credits can be gained from a thermographic inspection of the building envelope to confirm:

• Continuity of insulation in accordance with the construction drawings
• Avoidance of excessive thermal bridging
• No air leakage paths through the fabric

With rising energy prices and the need to comply with approved document L of the Building Regulations, England and Wales or Part 6, Scottish Standards there is a particular need to focus on the operational energy performance of buildings. Roof and wall cladding systems incorporating Corus Colorcoat® pre-finished steel liners and outer sheets are detailed to optimise current design practice, reduce air leakage paths and minimise fabric heat loss through the building envelope. The Colorcoat® Technical paper Creating an air-tight envelope explains how good air-tightness using steel-based envelope systems can easily be achieved.

How can material selection influence the BREEAM rating?

Materials

Of the seven materials categories considered under BREEAM, two are relevant to the specification of the cladding material. These relate to the environmental impact of the materials used (Mat 1) and responsible sourcing of products (Mat 5).

Mat 1 - Materials specification

Under BREEAM, the environmental impacts of construction products are assessed using the BRE’s Green Guide to Specification. The Green Guide gives a rating for a range of specifications of major elements of different buildings types. Specifications are rated on a scale of A+ to E. Steel envelope specifications incorporating Corus Colorcoat® pre-finished steel achieve the highest ratings (A+) within the Green Guide enabling top BREEAM credits to be achieved under this category.

Mat 5 – Responsible sourcing of materials

Increasing attention is being paid to responsible sourcing of construction products and this is reflected in BREEAM 2008. Under this category, up to three credits are awarded for demonstrating that more than 80% of materials have been responsibly sourced. In the UK, 100% of Corus’s sites are certified to the EMS standard ISO 14001 and in addition, many of the leading profilers of cladding systems which incorporate Corus Colorcoat® pre-finished steel are certified to ISO 14001.