In February 2019 MBIE released a document entitled "Building Performance Guide: Fire Performance of External Wall Cladding Systems". This document includes a simplified risk assessment approach to classify a building's level of complexity and fire risk as either Low, Medium or High. The parameters that influence the risk include:

• Building at height
• Vulnerability of risk group
• Provision of an automatic fire sprinkler system.

Buildings that fit into the High Risk classification have four available fire testing protocols. The Project Fire Engineer can accept an external wall cladding system tested to any one of these four protocols as well as a cladding system that falls within strict prescriptive parameters.

In GIB® News Issue 2 2019 we described the successful testing by cladding manufacturers in accordance with the NFPA 285 protocol P3 method. More recently we have tested 13mm GIB Weatherline® as a cladding substrate in accordance with the more severe protocol P2. In protocol P2 the external wall cladding system, which includes the substrate, must meet the performance criteria given in BR 135 following testing in accordance with BS 8414.

The 9 metre tall BS 8414 test panel consisted of 90 x 45mm timber framing fixed to a steel support frame. This timber frame received a 10mm GIB® Standard plasterboard lining to the internal face, Pink® Batts® cavity insulation and 13mm GIB Weatherline® Rigid Air Barrier to the external face. Solitex Extasana Adhero® self-adhesive membrane was applied to the face of the 13mm GIB Weatherline® before an external cladding system consisting of Paneltec Induracore G2 was installed.

This successful test returned a great outcome and established that the cladding system described above met all the performance criteria given in BR 135, thereby satisfying MBIE protocol P2.