The landscape of construction regulations is constantly evolving to ensure safety, durability, and sustainability in our built environment. Among the recent updates, the Building Code of Australia (BCA) has introduced significant changes to the corrosion protection requirements for structural steel. Effective as of May 1, 2024, these revisions aim to enhance the longevity and resilience of steel structures while aligning with contemporary environmental standards.

Previously located in Volume 2, the new corrosion protection requirements can now be found in Section 6.3.9 of the ABCB Housing Provisions Standard 2022. The essence of these changes lies in their alignment with environmental considerations, adopting the same definitions as outlined in AS/NZS 2312.2. This shift underscores a holistic approach to corrosion protection, recognizing the diverse conditions structures may encounter.

One of the pivotal updates is the establishment of minimum requirements for corrosion protection coatings, which now encompass options like Hot-Dip Galvanizing (HDG), paint, and duplex coatings. All coatings must comply with either AS 2312.1 or AS/NZS 2312.2 standards, ensuring uniformity and reliability across the board. Notably, the days of applying two coats of generic “house paint” to un-blasted steel are over, as the new code mandates adherence to specified standards for all coatings.

Pre-galvanized hollow sections receive a nod as deemed-to-satisfy solutions in low corrosivity areas (C2), provided all cut ends and damages are adequately addressed. This recognition of pre-galvanized materials reflects a nuanced understanding of corrosion risks and mitigation strategies, streamlining compliance for builders and designers.

Furthermore, the minimum requirements for HDG coatings have been refined to ensure a consistent lifespan of 15 years to first maintenance across different corrosivity zones. The specified galvanized coating mass is calibrated to achieve this longevity, drawing upon the corrosion rate of zinc delineated in AS/NZS 2312.2.

For products conforming to AS/NZS 4680 standards, batch HDG coated steel finds application in areas of medium (C3) and high (C4) corrosivity, with provisions for even the most challenging environments near breaking surf (C5). The delineation of corrosivity zones offers clarity for stakeholders, enabling informed decisions regarding suitable corrosion protection measures.

In recognition of the industry’s need for transition, a grace period until May 1, 2024, allows for the continued use of requirements from the 2019 code. However, stakeholders are encouraged to familiarize themselves with the updated provisions to ensure compliance and optimal outcomes.

These changes herald positive implications for homeowners, designers, builders, and galvanizers alike. By harmonizing corrosion protection standards with environmental factors and technological advancements, the revised BCA requirements pave the way for safer, more resilient steel structures. As we embrace these updates, collaboration and ongoing education remain essential for navigating the evolving landscape of construction regulations.

Further information can be found in this article. Embracing these changes collectively, we reinforce our commitment to quality, durability, and sustainability in the built environment.

(Photos thanks to ETS Architects)