Following changes incorporated in the National Construction Code 2019 Volume One (NCC), as proposed by Forest and Wood Products Australia, all multi-residential and non-residential buildings can now be constructed using “fire-protected timber” [refer NCC Specification C1.13a] building elements for the construction of buildings up to 25 metres in effective height (typically eight-storeys); referred to as “Mid-rise Timber Buildings”.
These fire-protected timber elements, under the NCC Deemed-to-Satisfy Provisions, require a minimum of 2-layers of 13mm fire-protective grade plasterboard for lightweight construction and 1-layer of 16mm fire-protective grade plasterboard for massive timber (e.g. minimum 75mm thick laminated veneer panels) to achieve the Resistance to the Incipient Spread of Fire (RISF) criteria. Building and design professionals also need to ensure that these layers are adequate to achieve the required Fire Resistance Level (FRL) for the specific class of building being designed – if not, additional thickness or layers of fire-grade plasterboard are required. Other fire-grade protective board coverings may also be used if they have been tested/assessed to achieve compliance with the RISF requirements of Specification C1.13a.
One way to demonstrate this is to provide the appropriate documentary “...evidence to support the use of a material, product, form of construction or design...” which can be in the form of a report issued by an Accredited Testing Laboratory [refer NCC Clause A5.2(1)(d)].
Wesbeam, in collaboration with Forest and Wood Products Australia, has undertaken the appropriate full-scale load-bearing fire testing of its “e-beam” and “e-joist” floor joist products to enable them to be used in fire-rated load-bearing floor/ceiling systems in mid-rise timber buildings.
Wesbeam’s e-beam and e-joist have successfully been tested as floor joist products within a fire-rated lightweight floor/ceiling system assembly in accordance with AS 1530.4:2014 Methods for fire tests on building materials, components and structures – Fire-resistance tests for elements of construction and have achieved an FRL 90/90/90 and FRL 120/120/120 utilising 2-layers (RIR 37600400D.2) and 3-layers (FAS190034-RIR D1.0) of 16mm fire-grade plasterboard respectively – reports (in brackets) issued by Warringtonfire Australia Pty Ltd. These reports provide the required evidence of suitability in accordance with the NCC and can be found and freely downloaded here.
Additional test reports for mid-rise timber buildings can be found on the Forest and Wood Products Australia’s “WoodSolutions” website. Here you can download an assessment report (RIR 37401400.1) from Exova Warringtonfire Australia Pty Ltd (now Warringtonfire Australia Pty Ltd) that provides and assesses various fire-protected timber wall and floor system details “...when elements interface with other forms of construction, have additional coverings applied or are penetrated by services or fire doors” that can be used in conjunction with the Wesbeam fire test reports.
Other useful technical resources available to assist with the design and construction of mid-rise timber buildings include:
For further information on Wesbeam’s LVL products and building systems for the construction of mid-rise timber buildings, please contact david.bylund@wesbeam.com
Article written by Boris Iskra, TPC Solutions (Aust). You can contact Boris at: iskra@tpcsolutions.com.au