Aluminium composite panels have been used for decades in many developing countries and for more than 30 years in Australia.
As a lightweight and cost effective construction method for external cladding, particularly for high rise buildings, they are preferred materials for industry stakeholders and commonly specified by architects. They are a preferred product compared with older and heavier alternatives such as concrete, brick and aluminium.
However, has Australia and its Building Code (BCA) kept abreast of the most reliable and consistent product testing methods? This is paramount to ensure that properly fire rated aluminium composite panels (ACPs) are recognized as compliant, and to make certain that unsafe products with high levels of combustibility are not allowed to be used on buildings unchecked.
The construction industry was rocked by the vertical fire spread in the Lacrosse high-rise apartment building in Melbourne in late 2014. On this occasion an ACP product manufactured in China known as Alucobest had been used on the apartment building as external cladding, and a fire ignition on a balcony resulted in a serious and swift spread of fire upwards via the cladding material.
Everyone is also aware of the tragic Grenfell Tower incident in London earlier in 2017, involving another residential apartment building. There is a school of thought in the British architectural field that this was not an unavoidable “act of God” but the result of a trend toward privatization of public safety and the diminution of architects having the authority to insist on specific products being used. This has, of course, led to developers trending toward cheaper materials without being cognizant of the potential for tragic consequences. Other disturbing British trends that may have contributed to the Grenfell Tower incident include:
- the under-resourcing of council building departments and at the same time the partial privatization of building control, with a growing pressure on the private sector for easier approvals
- a new form of self-certification with the onus on the developer/owner to ensure that building work meets the requisite fire safety regulations, and less reliance on fire officers to certify compliance
- a growth in the use of performance based specifications enabling alternative materials for such items as cladding where such materials are selected by the developer or their contractors. This comes back to the fact that previously, architects would specify the products and could insist such products were used.
As ever, there are lessons to be learned here in Australia from the experience overseas. In Australia as in Britain, there is pressure to get buildings out of the ground as cheaply and as quickly as possible, with the partial privatization of building control and the tension between strict building regulation on the one hand and the economic demands of a project on the other. Architects also will feel this demand from developer clients keenly and the conundrum will be that the cheapest product is unlikely to be the safest course.
Many in the building surveying industry feel the Lacrosse apartments incident is not so much a sign that building industry practitioners are acting in breach of the BCA. Rather, many of these stakeholders feel the incident should lead to a review and clarification of the Building Code and potentially a tightening of its provisions. In other words, the view is that the problem resides with the BCA itself rather than the building practitioners’ interpretation of it.
Various types of aluminium composite panels are available to the market to be utilized as external cladding, lining or attachments, with a range of different manufacturers/suppliers. Critically, there is a variation in the composite components of ACPs, which of course means that some ACP products will have less combustibility, and thus higher levels of fire resistance than others.
It is the view of many that the provisions of the Building Code, including the adopted product testing regimes, have not been able to keep abreast of the wide range of external cladding products available, which vary significantly in material composition, method of installation and degree of fire safety.
Deemed to satisfy or performance based solution?
Specification C1.1, clauses 3 and 4 in the Building Code stipulate that external walls of buildings of Type A and B construction must be built out of non-combustible materials.
That said, clause 2.4 of Specification C1.1 allows concessions – this clause allows that any lining or finish or attachment can be combustible subject to limits on fire hazard properties of the materials (although this is also subject to conditions regarding façade fire spread and linings near exits).
In a recent technical paper, the Australian Institute of Building Surveyors (AIBS) said, “Clause 2.4 does not prohibit combustible material…in some instances material may contain combustible elements.”
The position then is not an absolute one, because combustible elements may be permitted if the overall product achieves a sufficient fire resistance rating.
In fact, various composite external wall materials (ACPs) were found to come within “deemed to satisfy” considerations in the Building Code, both prior to and after the advent of BCA 2006. It was this edition of the Building Code which first introduced performance provisions in relation to construction of external walls with ACPs (namely provisions CP2 and CP4).
Clause C1.12(f) of the BCA states:
The following materials, though combustible or containing combustible fibres, may be used wherever a non-combustible material is required:
…(f) Bonded laminated materials where-
(i) each laminate is non-combustible; and
(ii) each adhesive layer does not exceed 1 mm in thickness; and
(iii) the total thickness of the adhesive layers does not exceed 2 mm; and
(iv) the Spread-of-Flame Index and the Smoke-Developed Index of the laminated material as a whole does not exceed 0 and 3 respectively.
There is a misconception that use of ACPs as an external wall system can only be assessed as an alternative solution (ie based on the “performance based” requirements rather than the deemed to satisfy (DTS) BCA standards). This is not the case; in fact composite external wall systems are DTS solutions under the Building Code.
This is not to suggest that ACPs will necessarily pass the testing methodology associated with the DTS provisions. In fact, under the current inadequate testing methodology pursuant to AS1530.1-1994, many ACPs are unable to pass that test and must in the alternative fall to be approved as a performance based alternative solution only.
The alternative performance based route has its own problems and is not necessarily reliable, potentially allowing unsafe products to be used as cladding or lining materials.
For starters, if an alternative solution is utilized to assess the use of ACPs as wall cladding on a building, this will be an expensive and time consuming exercise. Not only the product itself but its installation method and other elements of the overall building structure will also need to be subject to a verification methodology (an engineering report) to substantiate that the alternative solution meets the performance requirements in a manner that is equivalent to or better than the DTS provisions.
Inadequate testing method under the Building Code
Currently the Building Code adopts for ACPs the Australian Standard test via AS1530.1-1994. External wall cladding is deemed ‘non-combustible’ on a DTS basis if it passes this test.
This is a small scale test that does not assess all elements of the composite panels holistically and is not an internationally recognized or calibrated testing methodology.
An expert report regarding fire code reform states that “This type of test was developed over 50 years ago and has shortcomings. It was intended for homogenous materials, not products that are faced, coated or laminated…The range of materials passing the test is relatively restricted but would include concrete, brick, steel, aluminium and mineral fibre insulation.” (Fire Code Reform Project Report FCRC PR 00-03, Fire Performance of Materials, Fire Code Research Reform Program April 2000)
When reviewing a copy of the Standard (AS1530.1-1994), it clearly states that “this test method is not applicable to products which are coated, faced or laminated. In such cases, tests may be carried out separately on the individual materials from which the product is formed and this shall be clearly stated in the test report.”
This small scale testing method of placing a small specimen into a furnace at 750 degrees Celsius and measuring differential temperature rises leads to an inherent risk that only a small specimen of the composite product is being tested. The result could be that unsafe ACP products could make it “through the net” as it were.
Therefore, it seems clear that the test method in AS1530.1-1994 is not applicable to coated products such as ACPs. It is also failing to test mixed products such as ACPs in regard to their combustibility as a “whole” or entire product. This does not recognize the composite nature of the ACPs and the extent to which such products have advanced in the market over the last few decades.
Aluminium composite materials (such as ‘honeycomb’ ACPs) are not able to pass this testing method because they are not designed for laminated products such as this.
There is a proposed new standard to be implemented, namely AS5113, which will have a testing methodology under BS8414. However, once again this test is a new method that is not utilized by any other country in the developed world and is not an internationally recognized or calibrated test method.
If the examination method under BS8414 does not involve full scale testing of the product (testing the cladding material as a whole), then the new standard AS5113 will not be effective to fill the gap in the Building Code and will be insufficient for improving public safety and public confidence in the reliability of ACP cladding products.
In fact, the majority of European nations and the United States currently employ full scale (not small scale) façade testing methods for combustibility, which are internationally proven and consistent test methods. These tests take into account the overall composition of the product, not just specific elements of it in isolation.
If in doubt about your rights and responsibilities in these matters, do not hesitate to engage expert advice and assistance from lawyers well versed in Victorian building regulation.