It can be said that the year 2018 and 2019 also mark a turning point in strengthening building regulations in line with thematic and prescriptions already implemented worldwide and at national level. These are the International Fire Engineering Guideline, the so called National Australian Built Environment Rating System (NABERS) and Green Star rating system. These regulations until now, have never being closely incorporated into the Building Code of Australia.
The 2019 amended BCA introduces a method of assessment of compliance called Verification Method (VM) introduced for almost 40% of the compliance requirements of the BCA. The VM is a method of assessment mainly quantitative, based on evaluation methodologies such tests, inspections and calculations. These methodologies are used during an analysis of the building and the results of this analysis is compared with a target that the design solution must achieve.
While the VM are applied systematically with the new BCA changes, the thematical regulations introduced are mainly concerning two main fields: Environmental sustainability applied to building and building safety.
Closely, the first group includes changes in relation to: Energy efficiency, condensation management, roof top spaces plumbing, accessible adult change facilities, while the second thematic group includes additional measures in relation to fire safety, bush fire, access to the building and in relation to the ability to use a bonded laminated material (Bonded laminate concessions), with specified characteristics and controlled fire hazard properties.
The characteristic of the first thematic group is the focus on other aspect not directly related to the safety of the building but rather connected to the level of comfort and the liveability of the built environment. Here technologies are introduced and applied to the building design such as principles of physics to increase the comfort in the building, thermodynamics leading to energy reductions and movements of air to allow enough ventilation.
As pointed out by a number of experts in the field of energy efficiency in construction (1) the 2019 changes to the BCA in terms of building sustainability related to the first thematic group have been introduced with the general aim to reduce the level of energy consumption of the building in general by 35%. To achieve this objective new VM are prescribing calculations to assess and evaluate the building energy consumption. This system is also used by NABERS and Green Star building energy rating systems. These calculations are applied to measure and evaluate carbon emission, water consumption energy efficiency and waste produced of the building at a given location.
The characteristic of the second thematic group is the focus on aspects related to the safety of human movements and hazards generated by design solutions of the building. Safety in construction embodies the aim to perform a full compliance of the building in relation to its classification and use.
The 2019 changes to the BCA are prescribing a fire sprinklers system for building apartments with 4 or more storey and less than 25 metre of effective height. This is a significant improvement in terms of safety which reduces a risk from the existing system with no fire sprinklers protection for those buildings.
As stated in the outline of the objectives of the 2019 changes to the BCA (2), the main reason that causes the new package of measures focussing on the safety aspect is to minimise the case of non-compliance of building with the already existing safety standards.
Reasons for this are to be found in giving a response to a number of cases of structurally unsound and fire unsafe buildings which had caused a number of life-threatening episodes in Australia capital cities. Those episodes once investigated where found produced by buildings non-compliant with the BCA. Most of those cases unfortunately are referred to the very recent past.
This is the case for example the Lacrosse tower building in the area of the docklands in Melbourne where cladding external lining material recommended by the Architect on the façade of the building caught fire threatening the apartments.
Similarly, is the case of the Sydney Opal Tower, a cutting age skyscraper part of a new requalification of the former Olympic village of Homebush Bay now turned into residential quarter in of Sydney urban fringe.
After the construction process being concluded and the tower being occupied by tenants, multiple sings of structural collapse occurred causing authorities to evacuate tenants and to initiate a process of structural verification consisted in series of tests of integrity accompanied by provision of structural props. Findings and a review of the building documentation against the BCA have highlighted the fail of compliance. This mainly due to poor control by Authorities over the process of approval and of conflict of interest between the Principal Certifying Authority, which gives the final approval of the building, and the developer.
More recently, another complex in the Sydney airport quarter, the Mascot Towers, was subject to structural issues resulting to evidence of cracking in its support structure. This case has made headlines on Local newspapers. As in the Sydney Opal tower, here were also evacuated.
Typically, accidents concerning safety and health monitoring of buildings have been considered as part of the risk of the industry, but the developing number of cases have increased doubts on the efficacy of the laws and on the compliance to building regulations and if procedures were observed or rather invalidated during the construction process.
After investigations have shown that the materials used was non-compliant and not properly considered by Architects, Builders and fire Engineers- but nevertheless approved as compliant in the final specifications, political representatives of the different social groups immediately have pointed their fingers on the lack of rules on the construction industry in regrds to the control on the approvals and on the existing rules ,being inadequate especially for a development of this importance. Re-writing new rules would have not only achieved a positive effect on the on the real estate with implications on the economy, but also ethically would have a benefit to the right- to be safe, a key and fundamental demand expressed by the civil society.
The feeling of a need of security, of an introduction of principles and rules based on a more rigorous methods, have been translated into to a recognition of the inadequacy of the satisfaction of the process to assess the performance requirements included in the BCA.
Attention have then turned on the how the existing BCA achieved the Performance Requirements. This is by satisfying the so called Deemed to Satisfy Provisions (DSP), a benchmark which lead to a satisfaction of a compliance, usually demonstrated by Architects and building designers or by their professional consultants with a written report.
The assessment of the DSP reflects the complexity of the relationship between the BCA and the process design of a building and also it outlines the points of conflict between those disciplines living open legislative areas to interpretations.
My view is that the Verification Methods introduced with the 2019 changes to the BCA is reflecting a certain difficulty to fit in with the existing system of the so-called Alternative Solutions (AS). The Alternative Solutions are the areas where the flexibility of the BCA is most evident: if a building solution does not fully meet the DSP, it can still be approved, as long it can be demonstrated that the solution meets “in principle” the relevant performance requirement. In other words, where a single design solution does not generate compliance with the DSP there are a series of ways to came closer to the compliance that can be also acceptable: When there is no solution to the problem, a series of solutions combined together and closer to the one that complies can also be acceptable.
An interview with the Director of one on Sydney major BCA consulting firms, Stuart Boyce (3) has underlined the struggle to find the presence of some Verification Methods in certain sections of the BCA rather than others, In fact, as he has commented, the VM can be found not only in both the mentioned above thematic groups but also across other areas of the BCA.
Nevertheless, this effort is to be found in the way that those Verification Methods relate to the existing structure of the BCA in relation to specific topics.
The effectiveness of a method of assessment based on calculations and mathematical models is more suitable with areas where modelling is at base of the evaluation taken like the building energy efficiency.
A comprehensive analysis of the 2019 changes and the implications regarding energy efficiency applied to building have been done by Paul Bannister and Hongsen Zhang (4). They have concluded that the 2019 BCA changes represent overall a positive outcome from the point of view of the energy efficiency and the implications on climate change.
In fact, not only there is a percentage from 31 to 49 of reduction of greenhouse emission, but also these reductions have as a result lowering the capital costs for the building proposed. At a small scale, an attempt is made to provide some answers to the increasing concern of climate change that is affecting the planet worldwide where the construction industry has a key role.
The changes related to this thematic group are involving the introduction of several new Verification Methods. These based on an on-line compliance table determined in conjunction with NABER and Green Star rating system.
The VM is also applied to measure against the physical phenomenon of condensation. These measures aim to mitigate the condensation which occurs in building and depends from activities around the building structure such air pressure, temperature and humidity. In this section of the BCA the Verification Methods, all mandatory, increases from 1 to 3 including two additional options of modelling of calculation the comfort and the air pressure movement in the interior of the building.
In summary, the VM here are used in a context, the energy efficiency section of the BCA which is mainly quantitative, already structured on the relationship data-result, an evaluation based on calculation rather than on comparative assessments and therefore find its natural continuity with the structure of the code.
Such quality is, at the contrary, is not present in the changes in relation to the topic of building safety. Here a new VM is introduced: a fire safety Verification Method accompanied by a series of advisory notes such as the concession of a fire rated bonded material to be allowed “in lieu” of a non-combustible material.
The fire safety Verification Method introduced within this thematic group prescribes a minimum of 12 “design scenarios”, each of them considered in one or more locations. The design solution it is nominally compared the reference building in one of the design scenarios to achieve compliance with the performance pollutions of the BCA.
Also, as it is specified in the Fire Safety Verification Method Handbook (5), this VM not only is non mandatory but also, as outlined in the National Construction Code 2019 Review by Engineers Australia (6), “in its current form not be implemented until a review of the method is undertaken using a sample of warehouses to test the veracity of the method.” An example of an uncertain contribution to the assessment of the fire risk with a little effect on applyng a rigorus model to improve the existing fire safety compilance.
It can be concluded that the 2019 changes to the Building Code of Australia have outlined a diversity of scenarios. This mainly derives from the introduction of a rigorous methodology of assessment, the Verification Methods witch effectiveness is depending on the thematic areas of application. The 2019 changes, in line with international standards of legislation, have showed consideration on preserving preserve the originality of the BCA: a legislation which contain a grade of flexibility rather than an unchallengeable calculated set of rules. Such flexibility is a characteristic that makes the BCA a solid example of building construction legislation worldwide.
Shedy Chris, ‘New standards help keep Australia’s Buildings standing come fire or flood’, in Create, Engineers Australia- February 2019
Interview with Stuart Boyce, Director of BCA Logic, Sydney June 2019
Bannister Paul, Zhang Hongsen, Building Performance Improvements from NCC2019, paper for AIRAH and IBPSA’s Australasian Building Simulation 2017 Conference, Melbourne, November 15-16- 2018