Requirements for the design and inspection of buildings around the world should be calibrated according to the level of risk which different buildings present, a webinar has heard.

During a recent webinar hosted by Engineers Australia, three members of the International Buidling Quality Centre (IBCQC) outlined the principles behind the IBQC’s Risk Based Classification and Mandatory Inspection Guidelines.

Panellists included Adjunct Professor Kim Lovegrove, IBQC Chair; Professor Robert Hertle, an honorary professor with the School of Engineering and Design at Technical University Munich in Germany; and Neil Savery, Managing Director of ICC Oceania (an arm of the US based International Code Council) and the former chief executive officer of the Australian Building Codes Board.

According to Lovegrove, the importance of adopting a risk-based approach toward regulation which governs building design and mandatory inspections should not be underestimated.

As things stand, Lovegrove says there are many good building codes around the world.

However, few of these effectively calibrate design requirements according to the level risk which is inherent different types of buildings.

Even fewer still have linked a system of risk-based building classification to mandatory inspection requirements that are suitable and proportionate to the level of risk that is associated with particular buildings.

Broadly speaking, a risk-based classification and inspection regime aims to promote greater scrutiny of buildings which are considered to pose the highest level of risk.

As with many building inspection regimes around the world, risk-based inspection regulatory systems usually include a minimum number of phased inspections of all buildings.

However, risk-based systems typically afford greater priority to buildings which fall within higher risk classifications. Such buildings are subject a greater number of inspections as well as a higher level of rigour during each stage of the inspection process.

The result is that more attention is directed toward buildings where the consequences of failure are likely to be most severe.

Such systems have been gaining increasing prominence over recent decades.

Since 2005, elements of risk-based building inspections have been incorporated into inspection regimes of 18 different economies.

In a 2013 paper, the World Bank argued that risk-based inspection approaches had the potential to deliver substantial improvements in building quality and safety.

However, such regimes are far from universal.

In some jurisdictions, inspection protocols adopt an ad-hoc approach. Meanwhile, others allow for greater levels of self-certification.

Still others adopt a one-size-fits-all approach. Under these regimes, similar inspection requirements apply irrespective of the level of risk which is inherent for a particular type of building.

In the Australian state of Victoria, for instance, the same four mandatory inspections are needed for a detached, single-storey home as are required for construction of a 50-storey apartment complex.

Low, medium and high risk buildings

In response, the IBQC guidelines provide model guidance. This is intended to help governments, building regulators and others to design a building classification and inspection regime that is suitable and appropriate for the level of risk that is associated with particular buildings.

Under the guidelines, buildings are classified as being either low, medium or high risk.

The level of risk is determined by the magnitude of potential consequences which may result in the event of serious building failure. This could involve a full or partial structural collapse or the failure of critical fire safety features.

The guidelines then outline a mandatory inspection regime which is calibrated to the level of risk involved.

For low-risk buildings (such as detached homes, minor storage facilities and some types of agricultural buildings), the guidelines suggest a four-stage process.

Under the first stage, building officials would review plans before issuing building permits.

The building official would then carry out mandatory inspections at the stages of footings/slab, frame/pre-cast panels (upon completion) and final completion including an inspection of waterproofing and fitness for occupation.

For medium and high-risk buildings, the guidelines recommend additional inspections relating to areas such as fire safety, mechanical/air conditioning, electrical and plumbing and drainage.

When undertaking inspections for medium and high-risk buildings, meanwhile, the guidelines place a strong emphasis on peer review throughout the various stages of the inspection process.

This includes review from designers, engineers and other qualified professionals.

German and Australian Experience

During the webinar, panellists discussed both the German and Australian experience in moving to a risk based regulatory regime.

In the case of Germany, Hertle said that a strong move stemmed from the 2006 collapse of the roof on the Bad Reichenhall ice skating and swimming hall in which fifteen people died.

The collapse followed heavy snowfall. However, it occurred despite the volume of snow on the roof accounting for only around half of the required designed snow load and only around 40 to 50 percent of what the roof’s loadbearing capacity should have been after required safety margins.

The roof failed on account of a lack of maintenances and inspection along with modifications to the use of the structure throughout its life.

In the aftermath, the Bavarian Interior Ministry worked with the Association of German Engineers to develop a series of guidelines. These have provided important guidance for engineers  in relation to matters such as:

• the inspection of structures
• the development of recommendations for building owners about how any defects or structural deterioration should be addressed; and
• how the quality and safety of the structure should be maintained throughout its useful life.

The guidelines outline matters such as how inspections and maintenance should take place, how necessary information should be obtained and how to determine the relative importance of potential deterioration or defects.

These guidelines drew upon building risk classifications that were contained in the Eurocodes – a set of European standards which outline how structural design should be conducted across the European Union.

Compliance with the guidelines is not mandated under law.

Nevertheless, Hertle says that the guidelines have provided an invaluable tool to engineers which has positively impacted engineering practice.

In particular, the guidelines have provided an important tool which helps engineers to effectively advocate for necessary measures when dealing with building owners – who by law in Germany are required to ensure that buildings are adequately inspected and maintained throughout their life.

The guidelines have also provided a tool against which judges can assess whether or not this requirement has been fulfilled in the event of any litigation.

Turning to Australia, Savery says that movement has been far more limited.

In terms of building design, the National Construction Code (NCC) does incorporate some considerations regarding the risk profile of buildings.

However, the Code does this only in a limited way.

First, the Code specifies varying requirements for ten different classes of building.

These classifications, however, deal only with the building’s intended purpose and user profile. They do not account for other risk factors such as building size or complexity.

Over time, additional risk features have been added to the Code in order to address classification gaps.

In terms of structure, for instance, the NCC now imposes various requirements based on a building’s ‘importance level’. This relates to the potential hazards in terms of human life or impact upon other nearby structures that have the potential to occur in the event of structural failure.

In relation to fire safety, requirements vary according to whether a building is type A, B or C – a matter which is determined by a building’s classification as described above along with its height.

In the 2022 edition of the Code, a new provision was introduced that provided a definition for a complex building.

This definition brings together a number of criteria which may indicate that a building is of high risk.

At some stage in the future, this be used as a trigger for additional regulatory interventions to assist with the design, construction and certification of certain types of buildings.

For now, however, the provision remains dormant and thus has no effect.

As a result, the NCC as it stands responds to building risk levels in a manner which is piecemeal at best.

Beyond design requirements, inspection regimes differ vastly across states and territories and are barely correlated with building risk. This is despite a landmark report which was published in 2018 recommending that inspection stages be proportionate to risk.

As mentioned above, Victoria requires the same four stages of inspection irrespective of building height or complexity.

In Western Australia, there are currently no state-wide requirements for mandatory inspections.

Instead, inspection requirements are determined by the consent authority which reviews the application.

(Last December, the Western Australian Government announced its intention to introduce mandatory inspections. The Government has indicated that these will initially focus on commercial buildings and apartment complexes.)

Asked about whether Australia was likely to move further in coming years, Savery says he is not optimistic.

He stresses that decisions about legal requirements for inspection regimes are the prerogative of individual states and territories. And for the most part, states and territories are showing limited if any appetite for overhauling their inspection regimes.

Whilst inspection regimes along with third-party review were recommendations in the aforementioned report, meanwhile, indications from states about how and whether these recommendations will be implemented are limited thus far.

“I can’t speak with any confidence or surety that Australia will move down the path that is identified in the (IBQC) guidelines,” Savery said.

“This is simply because it is not on the program.

“It is not on the agenda to review the National Construction Code’s classification system. Nor is it on the agenda as I understand it of the individual jurisdictions – that is the states and territories – to necessarily have a wholesale change to their inspection regimes.”

(The Bad Reichenhall ice skating and swimming hall in Germany collapsed in 2006)

Engineers play a critical role

Finally, Hertle says the importance of adequate design, inspection and maintenance of buildings should not be underestimated.

He encourages engineers to play a critical role in this area.

“I think it is necessary to do proper maintenance (and) proper inspections for our structures,” Hertle said.

“This is important because this is an enormous amount of money involved (in the building’s construction) and we have to be very careful with it. That is one thing,

“But the other thing is that everybody who uses buildings and structures needs to be able to use these structures without hesitation that they can fail.

“We as engineers have the obligation to make sure that this behaviour of society will be normal behaviour and to give societies assurance that they can use our structures that we have designed and inspected as they would like to use them.”