Stainless steel triumphs in coastal conservation

Stainless steel triumphs in coastal conservation
ASSDA Member Stainless Steel Wire & Mesh has played a pivotal role in delivering a stainless steel coastal fencing solution that has now become the gold standard in ecological management and restoration efforts.

Situated in the Northern Beaches of New South Wales, Curl Curl Beach faces the full force of several coastal conditions, enduring relentless assaults from strong winds, salt movements, extreme temperatures, and high humidity. Classified as a C5 (Surf Sea-shore) category under AS 4312:2019 Atmospheric Corrosivity Zones, this beach demands infrastructure that can withstand nature’s harshest elements.

Australian coastal environments present formidable challenges for infrastructure due to their exposure to corrosive, abrasive, and humid conditions. Recognising these challenges, the Northern Beaches Council engaged Toolijooa Environment Restoration with the critical task of designing and installing a 450m coastal fence on Curl Curl Beach. The objectives were clear:

  • A minimum 15-year lifespan without replacement
  • Minimal maintenance in the initial five years
  • Mitigation of sand movements within the dune systems
  • Restriction of access to both dogs and people.
     

Stainless steel emerged as the material of choice for this demanding application, showcasing its superior tensile strength, corrosion resistance, and unparalleled longevity. In comparison to surface-treated galvanised steel products, stainless steel offers extended asset life and lower maintenance requirements, reducing inspection frequency and overall costs. See the table below for a detailed comparison.

Degradation rate and asset life by coating/material in very high corrosively zones*
Coating/material Asset life until complete failure** Average degradation rate (10-6 M/Year)# When maintenance is required
316 stainless steel 720 years 0.025 Minimal maintenance due to rain water
Hot dipped galvanised^ 3 years 6 From 2 years

Reference: Whole of Life Cost Comparison and Cost Benefit Analysis for Steel Structures Constructed in the Foreshore Zone, Griffith University, 2009.
* Corrosivity zones in line with ISO9223
** Table 16.2 Corrosion protection methods
# Table 16.1 Average degradation rates
^ 600 g/m2 in line with requirements from AS4680 Hot-dipped galvanised (zinc) coatings on fabricated ferrous articles


Stainless Steel Wire & Mesh, an innovator in converting galvanised wire applications to stainless steel, supplied its ‘Strong Lock’ product in grade 316 to meet the stringent requirements of the 700mm high coastal fencing. Notably, the Northern Beaches Council has now adopted stainless steel as the default specification for their coastal fencing needs.

Adam Burrows, Special Projects Officer for the Northern Beaches Council, affirms the significance of choosing stainless steel: “Stainless Steel Strong Lock has been vital in our dune restoration works. Today, we aim to build structures that will outlast us and endure into the future, minimising works for future generations. Galvanised steel wire cannot guarantee this in windy, sandy, and high salt environments.”

Australian councils are increasingly recognising the importance of whole-of-life cost considerations in material specifications for extended life and minimal maintenance. In 2009, a whole-of-life cost comparison report was published by Griffith University and the Gold Coast City Council that investigated multiple scenarios from the perspective of what would represent the most cost-effective solution for structures in the foreshore zone with a design life greater than 19 years when comparing hot-dipped galvanised steel, paint systems, duplex systems using both HDG and paint, or stainless steel. The study revealed that stainless steel was the most viable option based on cost alone.

"In the case of coastal fencing, stainless steel not only delivers improved financial performance but also enhances services and output."


Coastal fencing, often overlooked, plays a critical role in environmental conservation by facilitating dune restoration and protecting and rehabilitating local vegetation to enhance natural recovery. Stainless steel, with its unparalleled attributes, contributes significantly to maintaining and re-establishing a sustainable and diverse natural ecosystem. As this project exemplifies, stainless steel is not just a material, it’s a guardian of our coastal heritage and a promise for a resilient and enduring future.

This article was featured in Australian Stainless Magazine 79 (2024).

Authors

Lissel Pilcher