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What Type of Ventilation Do I Need for My Construction Project?

Best Practice

Ventilation is a legal requirement on Australian construction sites, and the type of system you need depends on your environment, the hazards present, and the regulations that apply to your project.

A system suited to a basement fitout will not meet the requirements of a tunnel project. Selecting the wrong approach puts workers at risk, exposes your business to regulatory action and can cause significant delays in project completion. This guide covers ventilation requirements for three construction environments: confined spaces, basements, and tunnels.

What is Commercial Ventilation?

Commercial ventilation is the engineered control of airflow within a workplace. It ensures air quality is maintained at levels that are safe for workers and is compliant with Australian standards and regulations.

A commercial ventilation system combines supply fans, extract fans, ducting, filtration, and, in some cases, atmospheric monitoring equipment. On construction sites, these systems are often temporary or semi-permanent installations that will need adjusting as the project progresses and site conditions change.

Why Do Construction Sites Need Commercial Ventilation?

Construction activity generates airborne contaminants; without ventilation, these accumulate to concentrations exceeding the workplace exposure standards set by Safe Work Australia.

Some of the most common hazards on Australian construction sites include

Respirable crystalline silica (RCS) – produced by cutting, grinding, and drilling. RCS causes silicosis, lung cancer and Chronic Obstructive Pulmonary Disease (COPD).
Diesel particulate matter (DPM) –a Group 1 carcinogen as classified by the International Agency for Research on Cancer (IARC).
Welding fumes – manganese, chromium, and other toxic compounds, depending on the materials being welded.
Chemical vapours –given off by adhesives, solvents, epoxy resins, and surface treatments.

Proper ventilation on a construction site dilutes these contaminants or extracts them at the source before they reach dangerous concentrations. It also controls acute risks such as oxygen depletion and toxic gas build-up, which can develop rapidly in enclosed environments.

There are also clear legal obligations. Under the Work Health and Safety (WHS) Act, persons conducting a business or undertaking (PCBUs) must eliminate or minimise risks to health and safety so far as is reasonably practicable. In most construction environments, adequate ventilation is a direct compliance requirement; failing to provide it can result in enforcement action, project stoppages, and legal liability.

Ventilation Requirements by Site

Every construction site presents a different set of hazards, access conditions, and regulatory requirements. Understanding what applies to your specific site is the first step in selecting the right commercial ventilation system for hire. Below, we break down what you need to know for each environment.

General Construction Sites

General construction sites, such as multi-storey residential builds, commercial fitouts, and civil works, still generate significant airborne hazards even when the work is taking place in open or partially open environments. Wind, weather, and site layout all affect how contaminants move across a site. In some conditions, natural airflow disperses hazards adequately, while in others, particularly in partially enclosed structures, stairwells, or areas where multiple trades are working in close proximity, contaminants accumulate faster than natural ventilation can clear them.

Common scenarios where you will need a commercial ventilation system on a construction site include:

Fitout and finishing works in enclosed floors of a building under construction, where solvent vapours, adhesives, and surface coatings are in use.
Concrete cutting and grinding in areas with limited airflow, which generates RCS at concentrations that can exceed Safe Work Australia exposure standards within minutes.
Multi-trade environments where DPM from diesel plants, welding fumes, and chemical vapours are present at the same time.
Temporary enclosures such as scaffolding and shrink-wrap systems used during facade or roofing works, which restrict natural air movement across the site.

Ventilation System on Construction Site

The type of system you need will depend on the size of the area, the trades working in it, and the duration of the work. Portable axial fans, ducted supply systems, and localised extraction units are all commonly used on general construction sites. A site assessment will identify the appropriate combination for your specific conditions.

Confined Spaces

What Counts as a Confined Space?

Australian standard AS 2865 and state WHS regulations define a confined space as an enclosed or partially enclosed space that is not designed for continuous human occupancy, has restricted means of entry or exit, and has the potential to contain a hazardous atmosphere or engulfment hazard.

On construction sites, confined spaces include:

Storage tanks and silos
Excavated pits and trenches
Sewers and culverts
Pipelines and ducts

Before any worker enters a confined space, you must assess atmospheric conditions and implement appropriate controls. This is a direct legal requirement under state WHS regulations across all Australian jurisdictions.

The Risks

Oxygen depletion is one of the most serious hazards in confined spaces. Normal atmospheric oxygen sits at 21%, and levels below 19.5% are classified as oxygen-deficient under Australian standards (Source: Safe Work Australia). At these levels, workers can lose consciousness within minutes. Toxic gases, including carbon monoxide, hydrogen sulphide, and methane, can accumulate quickly, particularly where ground gas ingress or nearby combustion equipment is operating. Heat and humidity further reduce safe working time.

Ventilation Solutions for Confined Spaces

You have two primary options for confined space ventilation:

Dilution ventilation: This introduces fresh air using portable axial or centrifugal fans with flexible ducting to reduce overall contaminant concentrations in the space. It is a good approach when the general atmospheric conditions in the space need improvement.
Local exhaust ventilation (LEV): This captures contaminants at their point of generation before they disperse into the wider space. Use LEV when your workers are producing specific hazardous substances, such as welding fumes, solvent vapours, or silica dust, in confined spaces.

Many confined space operations require both systems working together. Select your commercial ventilation system based on the dimensions of the space, the identified hazards, the duration of the work, and the number of workers inside.

Basement Ventilation

Why Basements Need Active Ventilation

Since basements lack natural airflow, they can quickly accumulate dust, carbon monoxide from diesel equipment, and other airborne contaminants without a proper ventilation system. This issue is further intensified during construction, as multiple trades working simultaneously, ongoing diesel equipment operation, and activities like concrete cutting and grinding introduce even more contaminants into an enclosed space that cannot ventilate on its own.

How does Basement Ventilation Work?

Basement construction ventilation relies on supply and extract systems working together. Supply fans push fresh air in while extract fans pull contaminated air out, creating a controlled airflow pattern across the workspace. For proper ventilation, position your supply and extract points carefully. Poorly placed equipment creates stagnant zones where contaminants collect, or it produces short-circuit airflow that bypasses the areas where your workers are present.

Your system needs to achieve adequate air changes per hour (ACH) across all occupied areas, with calculations based on:

The volume of the space
The type and scale of contaminant-generating activity
The number of workers on site at any given time

If you are working in a partially occupied building, your ventilation strategy must also prevent contaminant migration to occupied floors and comply with AS 1668.2, the Australian Standard for Mechanical Ventilation in Buildings.

Moisture Management in Basement

Basement construction sites regularly encounter moisture ingress from groundwater, concrete curing, and rainfall. High humidity can affect worker health and compromise material performance. Select equipment that is rated for damp conditions, and factor in dehumidification if your site assessment identifies moisture as a significant risk.

Tunnel Ventilation

Why Tunnel Ventilation is Different

Unlike open construction sites, tunnels have no natural air movement. Diesel Particulate Matter (DPM) from machinery, dust generated during boring and cutting, and fumes from blasting do not have a natural way to disperse in a tunnel. Without a specially designed ventilation system, the concentration of these contaminants at the working face can quickly exceed Safe Work Australia's exposure standards.

Types of Tunnel Ventilation Systems

The two main approaches to tunnel construction ventilation are longitudinal and transverse systems.

Longitudinal ventilation moves air along the length of the tunnel using jet fans or duct-mounted axial fans. It is practical during the construction phase because you can extend it progressively as the tunnel advances. Its limitation is that as tunnel length increases, it becomes less effective at the working face and moves contaminants through the occupied zone rather than extracting them at source.
Transverse ventilation uses dedicated supply and exhaust ducts installed along the tunnel length to introduce fresh air and extract contaminated air at multiple points. This produces more consistent air quality along the full length of the tunnel and is the standard specification for longer tunnels or where vehicle emission volumes are high. A semi-transverse configuration, using either supply or exhaust ducting rather than both, is a practical option that reduces installation complexity while addressing the limitations of a purely longitudinal system.

Choosing the Right System for Your Project

The right ventilation system depends on your ds, regulatory requirements, environment, hazard, and the scale and duration of your work. Each environment covered in this guide has distinct conditions, and each requires a ventilation approach designed specifically for those conditions. Identifying the correct system early in your project protects your workers from atmospheric hazards from day one, avoids costly fixes later, and keeps you compliant.

If you need to hire ventilation equipment for your construction project, the team at RVT Group can help. We work with clients in mining, defence, oil and gas, energy, and other industries across Australia, supporting them with their commercial ventilation system needs. Each engagement starts with a site assessment to ensure compliance and safety. Contact us today to speak with a specialist.