National Construction Code

Fire safety in High Rise Buildings

31/07/2017
Fire testing

A lot has been said and debated about the recent Grenfell Tower apartments’ fire in London. It is not intended to repeat or extend that here.

This is particularly important in the context of avoiding speculation on circumstances that are the subject of an independent inquiry by British authorities, the outcomes of which will be watched closely. This article focuses on the relevant fire safety requirements in Australia’s National Construction Code, the NCC.

Understanding that external wall cladding and/or assembly will, at a minimum, have contributed to the rapid spread of the fire at Grenfell Tower, it is important that appropriate steps are taken to minimise this potential from occurring in Australia, with a substantial body of work having already commenced following the Lacrosse apartments’ fire in Docklands Melbourne.

NCC Provisions

Prior to both events, and since its inception, the Building Code of Australia (as part of the NCC) has contained provisions for external walls to be non-combustible for most multi-storey buildings. The performance requirement identifies that they avoid the spread of fire within and between buildings.

Given this and many other features of the NCC, a new building constructed in Australia, built in accordance with the NCC, provides extremely high levels of safety. Further, based on what we know of the Grenfell Tower fire, such a building constructed today would not comply with the requirements of the NCC. This includes provisions that limit the spread of fire, alert occupants to the detection of smoke, facilitate evacuation and enable fire brigade operations. Specific requirements vary with building size, however, provisions in the NCC that achieve these outcomes for a typical high-rise apartment building include:

  • Smoke detection and occupant warning systems.
  • Fire-isolation of exits, such as exit stairs.
  • More than one exit for each storey to allow alternative means of escape should one exit become unusable.
  • Exclusion of smoke from exit stairs.
  • Fire sprinklers.
  • Fire-resisting construction to limit the spread of fire between apartments and between storeys.
  • Non-combustible external walls.
  • Resistance to collapse as a result of fire.
  • Features to assist fire brigade operations, such as fire hydrants.

It is also important to highlight the principal fire safety properties addressed in the different test standards in Australia:

  • Combustibility
  • Ignitability
  • Heat release rate
  • Surface spread of flame
  • Fire resistance
  • Smoke production
  • Toxicity

Fire Performance of External Walls and Cladding National Advisory Note

The key features of the NCC in relation to external wall claddings and wall assemblies was explained in detail in a National Advisory Note issued in 2016. In summary:

  • With the exception of low-rise buildings (typically single storey residential buildings and two storey commercial, industrial and public buildings) and single dwellings, the NCC requires that external walls must be non-combustible if using a Deemed-to-Satisfy Solution.
  • Non-combustibility of a material is determined by testing to Australian Standard
    AS 1530.1 Methods for fire tests on building materials, components and structures: Combustibility test for materials. The NCC also lists some low hazard limited combustibility materials that can be used where a non-combustible material is required.
  • The NCC Deemed-to-Satisfy Provisions also require that any attachments to the external wall must not impair the fire resistance of the external wall or create an undue fire risk to the building’s occupants as a result of fire spread or compromising fire exits.  Permitted attachments are generally incidental in nature such as a sign, sunscreen, blind, awning, gutter or downpipe.
  • If not following the Deemed-to-Satisfy compliance pathway, a Performance Solution for combustibility of external walls must be able to demonstrate that it will avoid the spread of fire within and between buildings, including providing protection from the spread of fire to allow sufficient time for evacuation.
  • In respect of suitability of materials to be used in a building, the NCC requires that every part of a building must be constructed in an appropriate manner using materials and construction being fit for the purpose for which they are intended.
  • The NCC mandates the forms of evidence that must be used to demonstrate the suitability of a product, form of construction or design.

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Photo: Full-scale fire testing being conducted on an external wall by Bre-Global Ltd.

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