More inspections of critical structural and fire safety features may be needed for higher risk and more complex buildings if a draft model approach to mandatory building inspections is adopted by states and territories.

The Australian Building Codes Board (ABCB) is reminding building industry participants of the opportunity to comment on a a draft model process for mandatory inspections of building work before consultation closes as the end of this week.

The model was proposed in one of three consultation papers released prior to Christmas.

It proposes a three-tiered approach through which items that need to be inspected during construction vary according to the level of complexity of the building in question (see note below) and thus the level of risk associated with the building.

First, there are buildings which are classified as being of very low complexity.

These are basically low or medium rise buildings (less than eight storeys) which are not Class 2 buildings (apartment buildings) of three storeys or greater, do not use performance solutions for structural or fire safety systems, are not in disaster prone areas, do not cater for more than 100 occupants or more than 10 occupants who need assistance in an evacuation and are not critical or hazardous buildings such as hospitals or gas plants.

For these buildings, the model proposes mandatory inspections at the stages of:

• structural frames (including roof construction)
• foundation
• in situ reinforcement in footings/slabs and other structural elements
• pool barriers including in-situ reinforcement for pools
• waterproofing of wet areas
• final, post completion of all work

Next, there are buildings which are either low and medium complexity.

Examples of the former include single family homes which lie within fire prone areas or warehouses for which performance solutions related to material or structural or systems for structural or fire safety have been adopted.

An example of the latter is a single use office building which caters for more than 100 occupants and which is either greater than 25 meters in effective height and/or has performance solutions which relate to material or systems for structural or fire safety.

In addition to the core features referred to above, the model proposes that for these buildings, inspections should also be mandatory for:

• any specific construction requirements relating to performance solutions
• façade and cladding installation
• fire detections and suppression systems
• pre plastering/wall lining including (where required by the NCC) thermal and acoustic insulation; sarking, cavities and other waterproofing and condensation mitigation measures; non-combustible elements
• Fire-rated compartmentation including external walls, floors, shafts, separation between buildings and protection of openings.

Finally, there are buildings of high or very high complexity.

Examples of High complexity buildings include an apartment building of over three storeys for which performance solutions related to material or systems for structural or fire safety have been applied and which caters for over 100 occupants (such as Lacrosse, Mascot Tower, or the Forte Building) or a small hospital in a cyclone area which is designed for more than 100 occupants and over 10 occupants who will need assistance to evacuate.

An example of a building of very high complexity includes a multiple use building including an apartment building of over three storeys, with serformance solutions related to material and systems for structural or fire safety, over 100 occupants and over 10 occupants who will require assistance to evacuate. The Opal Tower which has a child care facility is one such example.

Another example relates to buildings which are either associated with hazard facilities or are critical to post-disaster recovery. These could be a gas fired power plant, an emergency services facility or a major hospital.

For these buildings, the model suggests not only that inspections be mandatory for all the above features but also that witness testing be required for fire safety systems and emergency evacuation systems which are in operation.

(Note: The notion of ‘building complexity’ referred to above is likely to be adopted in the 2022 edition of the National Construction Code as the Commonwealth and States seek to apply more stringent requirements to buildings which represent a greater risk to occupant health and safety.

Under this concept, buildings will be classified as either being very low, low, medium, high or very high complexity. Buildings of greater complexity will be considered to represent a higher risk to health and safety. This is because there is a greater likelihood of these buildings being  constructed in a manner which fails to meet building code requirements and because the consequence of any non-compliant elements for the safety of occupants are likely to be more severe within these buildings on account of either the number of occupants for whom the building caters or the vulnerability of the population for which the building caters (elderly, disabled etc.) in the event of an emergency.

A building’s complexity will be determined by several factors including:

• the building’s attributes (height, use of performance solutions for structural stability or fire safety, locational risk)
• its classification under the NCC
• the number of occupants for which it will cater
• the likely number of occupants who will require assistance during an evacuation; and
• the ‘building importance level’ as defined by B1.2a in NCC Volume One.

In addition to specifying features which need to be inspected, the proposed model outlines requirements for other matters which relate to the inspection process.

These include:

• who should conduct inspections
• the stage of construction at which mandatory inspections along with any additional inspections should occur
• the percentage of construction which needs to be inspected (should every wet area’s waterproofing be checked in a multi-storey apartment complex or should this be restricted to only a percentage of wet area waterproofing?)
• documentation which is needed; and
• actions which need to be taken where non-compliance with building standards is detected during the inspections.

The proposed model comes as part of ongoing efforts to improve the safety of high-rise apartment complexes following the discovery of structural flaws in the Opal and Mascot Towers along with the discovery of flammable cladding on thousands of buildings throughout Australian capital cities.

The consultation paper for the proposed model is one of three papers which were released before Christmas.

In addition to the model processes for mandatory inspections described above, these papers also outline draft models for building design acceptance and third party review.

The draft models aim to promote greater national consistency in areas of building regulation surrounding design acceptance, third party design review and mandatory inspections.

They respond to findings and recommendations from the Building Confidence report prepared for the Building Ministers Forum by Professor Peter Shergold and lawyer Bronwyn Weir.

According to that report, Australia faces challenges with inconsistency in regulation across various states and territories across each of these three areas.

On mandatory inspections, for instance, that report noted that some states have no or very few mandatory inspections in domestic buildings whilst most states rely on the building surveyor to determine the inspections which are needed for commercial buildings.

Whilst they will not be mandatory within themselves, the proposed model codes aim to help foster greater national consistency in these areas by providing states and territories with a model around which to base their own approaches to regulatory reform.

Consultation on each of the proposed models closes on Friday.