By Koroush Keshavarz – Senior Associate-Principal Fire Engineer.
With so many lives lost in the recent Grenfell Tower fire, serious questions are beginning to be asked of the building management and local authorities about how fire safe the building really was, and whether the proper fire safety precautions were in place.
The cause of fire is still to be determined, however the rapid fire that spread throughout the façade of the building suggests that the cladding installed during the most recent building refurbishment is likely to blame. In addition, the fire was very similar in nature to both the Lacrosse Apartment fire in Docklands, Melbourne, and the Address Hotel in Dubai, where the façade cladding materials used were found to have accelerated the fires.
But façade fires are very complex in nature. They tend to accelerate quickly because they can be challenging for the attending fire brigade to fight as the debris of aluminium cladding falling from the building and fire simultaneously spreads upwards and out of reach of the fire brigade.
So, was the cladding solely to blame? The Grenfell Tower was originally designed with a concrete façade, but as part of the recent refurbishment aluminium composite claddings were attached to the building’s façade, possibly to improve the appearance. The aluminium claddings consist of two layers of aluminium sandwiching a core material. The core material can have combustible fillings such as polyethylene (in this case) or non-combustible filling such as mineral materials. Part of the investigation into the fire will need to examine the role these materials played in accelerating the fire, particularly if cheaper imported materials were used over certified products, as was recently suggested by the CEO of Boral: http://www.afr.com/real-estate/borals-mike-kane-warns-on-cheap-chinese-cladding-20170619-gwtz2g
The second consideration is that although the Grenfell Tower had 63.7m height, it was not initially fitted with an automatic fire sprinkler system. This hadn’t been retrofitted to the building as part of £8.7 million refurbishment either, even though current building regulations for tall residential buildings require the installation of sprinkler systems throughout. So, while the cladding may certainly have accelerated the fire, one of the most critical questions that needs to be asked is why the building management and other project stakeholders decided to omit the installation of a sprinkler system in the building. Having such a system in place will generally contain the fire within the room of the fire’s origin.
What does this mean for Australian buildings?
In Australia, all buildings with an effective height of 25m must be fitted with sprinkler protection, so it is primarily the façade issues that we are interested in in the Australian context.
For the development of new buildings and refurbishment of existing buildings, there are three key factors that should be taken into consideration to minimise the risk of accelerated façade fire:
- Check the latest BCA requirements and discuss the cladding materials with a building certifier or a fire safety engineer. The BCA only allows attachments to the building which will not contribute to the spread of fire in a building and between buildings – this is referenced in Specification C1.1 Clauses 3.1(b) and 4.1(b)). However, the code does allow for some external combustible components to be installed on the building if these attachments comply with the Performance Requirement CP2. This means the external materials must comply with the fire hazard properties prescribed in Specification C1.10 and not located near or above an exit. However, a certified fire safety engineer must assess the impact of installation of a combustible component to ensure compliance with the performance requirements of CP2 is achieved.
- Benchmark your products. Standards Australia has developed a new Australian Standard (AS 5113) for testing and classification of external walls of buildings in relation to the fire spread. Even through this standard hasn’t been referenced in the BCA yet, it provides a good benchmark for external wall products.
- Beware of using cheaper alternative products. Only products that have a CodeMark Certificate of Conformity.For more information refer to link below: