Ventilation

- and infectious diseases

All workplaces need good and efficient ventilation - what this means will depend greatly on the workplace itself, the work that is being done, the chemicals used, the workplace layout, the number of workers and other workplace conditions.

What is good ventilation in all workplaces, irrespective of workplace processes, plant and chemicals, has become increasingly important recently due to the COVID-19 pandemic and the fact that we now know that the virus is transmitted mainly via aerosols and less through contact with contaminated surfaces.

Good ventilation is a key measure in reducing the spread of airborne transmission of the virus in indoor workplaces. This can be achieved through improving ventilation in indoor venues, by opening windows, doors and optimising fresh air flow in the air conditioning system, and moving other activities outside where possible.

This page provides HSRs with more information and advice on what employers need to do to ensure that the ventilation in their workplace is as effective as possible.

The Problem

  • Inadequate or inefficient ventilation can lead to disease spread (as was seen, for example with the COVID-19 hotel quarantine outbreaks) 
  • When in a 'confined space', can increase impact of hazardous substances such as fumes 
  • Flammable materials and improper ventilation can lead to fires and burns 
  • Unsafe oxygen levels can lead to suffocation

Aerosol spread and COVID-19

While insufficient ventilation can lead to many hazards, the advent of the COVID-19 pandemic has made clear that proper ventilation and adequate fresh air circulation are essential to protecting workers from the spread of COVID-19. 

In early 2021, the World Health Organisation finally acknowledged aerosol transmission as the predominant form of COVID-19 transmission. For months many international experts had been asking the WHO to accept this and move away from the original idea that the virus was primarily spread through 'droplets' and surface contamination.  This confirmed that the virus can be spread through tiny particles from someone when they speak, sing, cough, sneeze or even just breathe. Ineffective ventilation in indoor areas means that these particles stay in indoor areas for longer and lead to increased COVID-19 transmission. There are already a large number of cases through workplace transmission and as more and more workers return to indoor workplaces, aerosol transmission of COVID-19 becomes a huge problem.

This risk is exacerbated further due to the fact that Australia’s air quality standards are outdated. The comprehensive set of air-quality standards was released in 2012 with an amendment in 2016. Consequently, current standards fall short in addressing the risks of aerosol transmission of COVID-19.

Perhaps the most significant and impactful example of the dangers of poor ventilation was the Melbourne hotel quarantine outbreaks of COVID-19 in 2020. It has been a requirement for travellers returning to Australia from overseas to quarantine for 14 days. Those returning to Melbourne were placed in 'quarantine hotels' where the ventilation, while adequate for hotel use, was not adequate for quarantine purposes. The outcome was that some travellers who were carrying the virus quarantined in the rooms - indoor enclosed spaces with poor ventilation.  (See: The Conversation

Poor ventilation meant that the virus stayed airborne in the hotel rooms, 'leaking' into the common corridors, when doors were open for a brief time, leading to another outbreak in Melbourne. The WHO published research in August 2020 outlining the risks associated with poor ventilation in hotel quarantine. WHO has also produced interim guidance Considerations for quarantine of contacts of COVID-19 cases

It is also important to note that the Australian Howard Springs quarantine facility - where rooms are spread out over wide open areas instead of enclosed, poorly ventilated hotel rooms - has not had leaks of the virus as of September 2021 (Leah Grout, et al Failures of quarantine systems for preventing COVID-19 outbreaks in Australia and New Zealand [Full article] Medical Journal of Australia.)

On top of the risks associated with COVID-19, additional risks associated with poor ventilation include a dangerous level of carbon monoxide in spaces with petrol and diesel vehicles and machinery and low oxygen levels in controlled atmospheric rooms (such as fruit storage). Further, using cleaning solvents or other chemicals in spaces with poor ventilation can lead to fumes or burns. For information regarding other health concerns associated with poor ventilation not related to the COVID-19 pandemic see - Confined Spaces and Poorly Ventilated Areas 

The Law 

Occupational health and safety legislation

1. Under section 21(1) of the Occupational Health and Safety Act 2004 all employers have a general duty of care to provide and maintain, so far as is reasonably practicable, a working environment that is safe and without risks to health. This covers everything in the workplace.

Broadly ventilation is also covered under Section 20, 21(2) and 22 of the Act:

  • Providing and maintaining safe plant machinery and systems of work
  • Maintaining the workplace
  • Monitoring the conditions at the workplace under the employers management and controlling ventilation related factors such as heat, cold, dust levels, fumes, and so on. 

2. Even if the employer does not own or maintain the building, section 26 of the OHS Act makes clear that if an employer has management or control of the workplace ‘to any extent’, they must make sure that workplace and the means of entering it or leaving it are safe and without risks to health (so far as reasonably practicable). 

3. Section 35 of the Act also makes clear the duty of the employer to consult with HSRs with respect to a range of factors related to exposure to COVID (see duty to consult).

Other - Australian Standards

4. While Australian Standards are not law unless called up in regulation, they form part of the 'state of knowledge' - which employers must take into account when considering what is 'reasonably practicable'.  (See: WorkSafe's guideline, made under Section 12 of the OHS Act, 2004 How WorkSafe applies the law in relation to Reasonably Practicable which explains the concept and its application. HSRs should ensure they have a copy for reference.)

5.  Outdoor air rates need to be a minimum of 10 litres/sec/person or better.
This is as per AS 1668.2 2012 The use of ventilation and airconditioning in buildings. Part 2: Mechanical ventilation in buildings. Generally Australian Standards recommend that ventilation rates for office spaces be set to 10 L/s/person for most workplaces. In certain workplaces this requirement is higher with nightclubs, hairdressers, games rooms, bowling alleys and ballrooms requiring a circulation of 15 litres per person a second.

6. Heating, Ventilation and Air Conditioning [HVAC] systems need to be regularly maintained and cleaned according to Australian standard AS/NZS 3666:2:2011 Air-handling and water systems of buildings - Microbial control Operation and maintenance.

 

What does the employer need to do?

As per the information above, under sections 20, 21 and 22 of the OHS Act, the employer is required to eliminate health risks so far as reasonably practicable. This means, so far as reasonably practicable, maintaining ventilation systems and ensuring that workplace ventilation is adequate so that the building is safe and without risk to health. This includes ensuring proper airflow to contain the spread of COVID-19.

This can include, but is not limited to: 

  • Monitoring the conditions at the workplace. A CO2 monitor can be helpful in assessing ventilation provision to aid ventilation opening modulation.  
  • Ensuring that heating, ventilation and air conditioning [HVAC] systems are regularly maintained and cleaned according to Australian Standards
  • Liaising with the building manager to make sure the HVAC system has been properly cleaned and maintained. If necessary requesting and providing written evidence of this in the form of a statement from a ventilation engineer that the system has been examined. 
  • Improving airflow in the building by opening windows, redirecting the flow of exhaust systems away from windows and doors and adjusting air conditioning settings to reduce or eliminate re-circulated air. 
  • Making sure that exhaust systems in restrooms and other facilities are functional and operating at full capacity when the building is occupied. 
  • If an HVAC system has been shut down because the workplace has been closed due to COVID-19 restrictions, the employer must also ensure that the HVAC system has been properly maintained while it has been shut down. This is crucial as Legionella bacteria may build up in shut down HVAC systems. The spread of this bacteria when the systems are restarted can cause Legionnaires Disease.  
  • Ensure that fresh air circulation in the building aligns with the Australian Standard AS 1668 Part 2. This requirement is 10 litres per second per person of outdoor air inflow in most workplaces. In certain workplaces, this requirement is higher with nightclubs, hairdressers, games rooms, bowling alleys, and ballrooms requiring circulation of 15 litres per second per person. For a comprehensive list of airflow requirements see Australian Standard 1668.2 2012, p.61. 
  • Additionally, if the temperature of the workplace exceeds 27 degrees, fresh air circulation needs to increase to 15 litres per second per person.

These measures should be used in conjunction with other measures such as physical distancing, staggered shifts and dedicated meal areas or break facilities, particularly where there are still concerns about the levels of indoor ventilation. If ventilation rates fall below the standard, the maximum room occupancy should be decreased and other preventative measures taken. 

Australian OHS law and our standards currently fall behind what is necessary in the era of COVID-19. However, the employer's mandate to ensure safety so far as reasonably practicable leaves HSR’s with the ability to push for a number of important best-practice ventilation standards not covered above. 

What We Recommend - Best Practice in COVID-Safe Ventilation

Rules and regulations regarding what is good workplace ventilation need to be updated as a result of the COVID-19 pandemic. HSRs are on the front line of pushing to get better standards in their own workplaces to achieve adequate ventilation. The following are a list of best-practice ventilation standards that HSRs can push for in the workplace:

  • Using high-efficiency particulate air filters [HEPA], particularly when bringing outdoor air inside is not an option. According to the US Centre for Disease Control (CDC), HEPA filters are 99.97 per cent efficient at capturing human-generated viral particles associated with COVID-19. HSRs should push their employers to install these in all enclosed office spaces. 

    A cost comparison of safe HEPA filters available on the Australian market can be seen below, the higher the M3/h delivery rate the more effective the filter. The smaller the blue bubble, the quieter the filter. 

  • Making sure that air quality standards are high enough to prevent the spread of COVID-19 and that fresh air is coming into the building. This can be done by putting Carbon dioxide (CO2) monitors in public spaces. CO2 concentration should be less than 800ppm, with below 600ppm considered best practice. Ventilation should be adjusted if levels go above this. Humidity levels should also be monitored and publicly displayed. COVID-19 fares worst in humidity levels between 40 and 60 percent.

  • Getting a filter on HVAC systems installed that is of a high enough standard to trap COVID-19 particles. The World Health Organization recommends an F8 filter or higher. The efficiency of filters in capturing all particulates in the air is highlighted in the table below. It is important to remember that COVID-19 particles are generally no larger than 5 µm and no smaller than 0.3 µm. The CDC estimates that an F8 filter is between 75 per cent efficient at capturing particles between 0.3µm and 1µm and 90% efficient at capturing particles between 1µm and 3µm.




  • The installation of Indirect Evaporative Cooling systems as these can ensure 100 per cent levels of fresh air circulation. 

Misinformation to be aware of

  • Some companies are promoting the use of UVC Lamps which purport to kill the virus using ultraviolet radiation. There are unproven/untested technologies, and in some cases dangerous. They can degrade air quality by producing ozone and ions which can trigger asthma. 

  • Using standing fans or air purifiers without HEPA filters to circulate air in an enclosed space is only safe if wind direction of these fans and purifiers is pointed away from any person in the room. Not doing so may have the effect of redirecting COVID-19 particles to the person in the direction of the fan.

Role of the HSR and what you can do: 
Action plan for HSRs 

Poor ventilation is a workplace hazard and as with all workplace hazards, it should be dealt with in this way:

  1. Identification of the hazard
  2. Assessment of the risk
  3. Elimination or reduction of the risk
  4. Review and evaluation of any control strategies

1. Identification of the Hazard

  • The employer needs to monitor the workplace and assess spaces where inadequate ventilation is a hazard, especially with regards to aerosol transmission of COVID-19. HSRs need to ensure their employer is doing this.
  • Speak to members of your DWG who may be experiencing problems due to inadequate ventilation or those who are at risk
  • Investigate any past incidents - have there been any reported infections, for example.

2. Assessment of Risk

The HSR needs to ensure the employer is:

  • Continuously monitoring of the workplace and reported incidents 
  • Monitoring of air quality 
  • Assessing whether the current ventilation system is regularly maintained and if it is compliant with the older standards.
    • Does it have the capacity to adequately reduce the risk of aerosol COVID-19 transmission - something that is not addressed in the current air quality standards

3. Elimination or Reduction of Risk

The HSR should:

  • Negotiate with the employer to implement proper controls
    • Are there air filters in place 
    • Are workers regularly tested for COVID-19 and given paid time off to get tested
    • Is air quality monitored for things like CO2, humidity and levels of fresh air circulation 
    • Is there a limit on how many people are in the space 
  • Ensure that the employer is regularly maintaining and cleaning heating, ventilation and air conditioning systems in line with Australian standards and COVID guidelines
  • Ensure that there is consistent airflow through open windows where possible, and regularly maintained air conditioners/ air conditioning systems 
  • Ensure that the employer is regularly maintaining exhaust systems in the workspace 

4. Review and Evaluate Control Strategies

The HSR needs to regularly check, through workplace inspections, consulting with the DWG and checking records that the controls implemented by the employer are maintained and are functioning properly. 

Consultation

Remember that in accordance with section 35 of the OHS Act the employer has a duty to consult with employees through either an elected OHS representative or directly with employees where there is no representative. An employer who does not involve HSRs in consultation is contravening this section and is guilty of an offence.

If there are concerns regarding the impacts of ventilation - or lack thereof - in the workplace on the health and safety of workers, OHS representatives and employees have the right to raise issues with the employer. If the threat is not immediate, the employer and the representative must try to agree on how to fix the problem, according to either the agreed workplace procedures - or if there are no agreed procedures, according to the issue resolution requirement under Chapter 2.2 of the consolidated 2017 OHS regulations.

If the HSR has consulted with the employer about fixing the issue and satisfactory action has not been taken they may issue a provisional improvement notice [PIN]. This cannot be ignored and needs to be resolved otherwise the employer must call a WorkSafe inspector to attend the workplace within 7 days of the PIN being issued. (See: Using a PIN)

In addition to issuing a PIN, a rep or employee can also contact WorkSafe or their union if these concerns have not been properly addressed by the employer. 

Sources and more information

Last updated October 2021