Fire and acoustic and energy efficiency standards
With the growing demand for multi-residential buildings in high density urban areas, the standards for providing safe, sustainable and liveable structures are more complex and stringent than ever. Being fully aware of these standards is essential when it comes to developing, designing and constructing Class 2 developments.
Fire resistance requirements
All walls for multi-residential dwellings are required to meet an FRL (Fire Resistance Level). This is expressed in the number of minutes the wall material will maintain its structural adequacy, integrity and insulation under fire conditions. It will be expressed as a series of three numbers for each element of resistance.
FRL requirements will depend on the class of building, the type of wall (internal or external) and the surrounds. For Class 2 (apartment) buildings, for example, external walls are required to have an FRL of 90/90/90. Additional fire rating standards may apply for dwellings in bushfire prone areas. Be sure to check with council and the Building Code of Australia (BCA) to make sure you’re aware of all fire safety requirements.
To limit noise from plumbing, appliance and day-to-day living, buildings with multiple dwellings and households need to comply with agreed standards for acoustic insulation. The acoustic performance of walls and flooring in reducing the transfer of sound is measured by the ISO standard for sound transmission loss, known as the weighted sound reduction index, Rw. The higher the rating, the better the acoustic performance will be.
There is an additional rating scale, Ctr, for low frequency sounds which can sometimes be transmitted by materials with the required Rw rating. Wall and flooring systems will need to comply with the relevant Rw and Ctr standards for different types of rooms and surfaces.
Energy efficiency requirements
The Nationwide House Energy Rating Scheme (NatHERS) was introduced to Australia in 1993 as a way to rate the thermal performance of residential buildings. The BCA introduced minimum energy efficiency standards in 2003. Since then, the required NatHERS rating for BCA compliance for Class 2 residential buildings has been increased to an average of six stars for all units in an apartment block, and a minimum of five stars for individual apartments.