Let’s start from the beginning. What is ventilation and why do we need it?
Ventilation is the provision of air from a clean outdoor air supply, to an indoor building.
A building requires clean air to:
- provide oxygen for inhabitants to breathe,
- dilute or remove air contaminants,
- reduces odours,
- provide thermal comfort,
- provide smoke control or smoke clearance.
Humans breathe in oxygen and breathe out carbon dioxide. Left un-moderated, this could be dangerous in a building with not enough oxygen in the building to service the inhabitants.
Ventilation can be either natural or mechanical or a combination of the two.
Natural ventilation can be achieved through openings in the external facade of a building. Windows, doors, vents and grilles are examples of this. However, in some buildings, natural ventilation systems are complex and controllable engineered systems.
Mechanical ventilation essentially uses fans to move air between the inside and outside of a building.
Indoor Air and Indoor Air Contamination
Indoor air can suffer from a range of contaminants from many different sources including
- organic substances such as microorganisms and microbial debris,
- pollens,
- animal hairs,
- metals,
- fibres,
- fine particles,
- and gases.
Microorganisms can include:
- Legionella pneumophilia
- Mycobacterium tuberculosis
- Moulds and mould metabolites
- Viruses
it’s critical that HVAC systems and air-handling systems are maintained in order to control microorganisms accumulating in building air systems.
The Australian Standard AS/NZS 3666.2 explicitly mentions the following 5 parts of an HVAC system that must be part of an HVAC cleaning program:
- OUTDOOR AIR INTAKES & EXHAUSTS – Inspect, clean or replace where necessary.
- AIR FILTERS – Inspect, clean or replace where necessary.
- HUMIDIFIERS – Inspect, clean or replace where necessary.
- EVAPORATIVE AIR-COOLING EQUIPMENT – Inspect, clean or replace where necessary.
- DUCTS & COMPONENTS – Inspect, clean or replace where necessary.
