As extreme weather events intensify, understanding and applying wind load standards such as AS/NZS 1170.2 has become essential for tradies across the country. Evelyn Long writes.

The world, including Australia, has been experiencing significant weather volatility due to climate change. High-impact shifts, such as severe storms and cyclones, present a challenge to the construction industry in ensuring the safety of workers and the public.

Understanding wind load standards is paramount in preventing delays, higher costs and reputation damage from structural failure in the event of calamities.

Every team of trade professionals and micro-builders must have a thorough understanding of compliance standards. This will protect your builders, business and customers.

What does AS/NZS 1170.2 mean for building projects?

AS/NZS 1170.2: Structural Design Actions, Part 2: Wind Actions is the gold standard for structural wind design actions, ensuring strong, safe and stable buildings during cyclones and high wind pressures.

Through analysis and detailing, Standards Australia’s committee of engineers determines the ideal materials, system design and other key factors.

AS/NZS 1170.2 is a primary reference used by the National Construction Code (NCC) and AS 4055:2021 Wind Loads for Housing is a simplified code specifically for housing based on AS/NZS 1170.2 principles.

Key factors in wind classification

When classifying winds, several factors come into play. The AS/NZS 1170.2 contains the following factors to determine the amount of force exerted on structures by wind.

Wind regions

Spanning 7.69 million square kilometres, Australia is the world’s sixth-largest country. Due to its vast size, the country is divided into four distinct wind regions based on meteorological data.

Region A covers most of Australia and is labelled as Normal. Regions B and C are upper coastal areas, classified as Intermediate and Cyclonic, respectively. Lastly, Region D, which stretches from Port Hedland to Carnarvon, is classified as Severely Cyclonic.

Builders from cyclone-prone areas, such as North Queensland, must follow stricter requirements to build stronger houses compared to those in calmer areas like Canberra.

Terrain category and shielding

Another key factor is the terrain or site exposure. Builders need to consider the surrounding environment of their project. Those built on flat, open fields are more susceptible to higher wind speeds.

On the other hand, buildings in dense, urban areas experience less force since they’re crowded by other buildings that receive the wind’s impact first.

Topography

Along with region and terrain, elevation is also a crucial factor in wind classification. Structures on steep hills are exposed to faster wind speeds compared to those built in low valleys. The height of the building is also an important factor, as taller buildings are also more prone to encountering higher wind pressures.

Manage on-site safety in high winds

To create stable structures, professionals must remain vigilant throughout the building process, from preparation to day-to-day management and construction. However, a design that complies with standards is only the beginning. You need to secure safety on the construction site at all times.

Ensuring equipment is functioning is the top way to safeguard your workers’ safety. For example, forklifts cause 20,000 accidents annually, according to data from the United States, so they should be inspected at least daily.

Since heavy machinery is left on the construction site, it is also affected by external forces. Especially during storms, debris can get into them. You must effectively prepare for general site safety and high-wind events. A comprehensive daily inspection can prevent:

• Hydraulic leaks
• Damaged tyres
• Damaged forks
• Fault engines, filters and battery
• Misaligned masts
• Unusable latches, seatbelts and finger guards

Some ways to secure your site and materials include implementing safety training, securing scaffolding, bracing and creating exclusion zones for incomplete structures and storing loose materials like bricks, insulation panels and roofing sheets.

After cyclones, storms and any other high-wind events, assess the site for shifts, debris and damage to materials or equipment. Also, examine the foundations for possible erosion that could significantly impact the structure’s stability.

Build a legacy of safety and strength

Dealing with weather changes has become an inevitable part of the construction process. Understanding and adhering to wind load standards is a crucial part of ensuring a safe environment for everyone involved. Determine your site’s wind classification, implement rigorous wind safety plans, and inspect all structures and equipment thoroughly and regularly.

Forward-thinking builders who adopt the latest standards, materials and technologies gain an advantage against competitors. By mastering these principles, you are one step closer to building a safer and more resilient Australia.