Natural Ventilation For Water Infrastructure

Natural ventilation typically involves simple systems and vents that use forces like wind and pressure to move air in water infrastructure. offering an efficient, low-cost and environmentally friendly method. However, performance can vary depending on environmental factors. 

Mechanical ventilation uses powered fans to force air out at a more controlled and consistent rate, but with a higher cost of installation and ongoing energy expenses. 

The best ventilation system for each facility varies depending on factors like the desired energy efficiency, the facility’s infrastructure and how crucial the need for consistent air exchange is.

The main Australian standards applying to water infrastructure ventilation include:

• AS 3666: Covers the best practices for designing, installing, commissioning, operating and maintaining water and air handling systems in buildings to ensure public health and safety. 
• AS 1668.1: Details fire and smoke control in ventilation systems, 
• AS 1668.2: Provides guidelines and compliance/safety standards for HVAC professionals to ensure indoor air quality and safe designs for mechanical ventilation systems.
  
• AS 2428: Sets out the requirements for louvres used in building ventilation, including rain/weather penetration, airflow and, when relevant, fire performances. 

For specific systems, you may also need to consult the following standards:

• AS 3500: Details plumbing and drainage standards, including guidance for venting and design requirements for water and sanitary systems.
• AS 3000: Covers relevant guidelines for electrical installations in water infrastructure. While not specific to ventilation systems, it governs safe electrical system design when creating housing water systems.

To determine ventilation requirements for a water treatment facility, follow these steps:

1. Measure the space
Calculate the length × width × height to determine the total volume (in cubic metres).
Example: A 1000 m³ enclosed pump room or processing area.

2. Determine the required air changes per hour (ACH)
Water treatment environments require different ACH levels depending on the process and hazard level.

Typical ACH ranges include:

• 3–6 ACH → general plant halls or open processing areas

• 4–6 ACH → enclosed plant or pumping rooms

• 3–6 ACH → enclosed reservoirs (air space above water surface)

• 6–10 ACH → chemical dosing or odorous gas areas

• 10–12 ACH+ → confined or high-hazard zones (e.g., chlorine gas storage)

To maintain safe air quality and meet regulatory expectations, Airocle recommends ACH targets aligned with Safe Work Australia and NCC ventilation guidelines.

3. Calculate the required airflow
Use the formula:
Airflow (m³/h) = Room Volume (m³) × ACH
Or in cubic feet:
CFM = (Room Volume in ft³ × ACH) / 60

Example:

• Room volume: 1000 m³

• Target ACH: 6

• Required airflow: 1000 × 6 = 6000 m³/h

This means the air within the space needs to be replaced six times per hour.

Maintenance for natural ventilation systems in water infrastructure includes regular visual inspections, cleaning key components like grills and actuators, and testing mechanical components (if the system has any). 

Natural ventilation systems are typically low maintenance, but depending on the environment, they may need more maintenance to ensure airflow is free of debris and that there is no damage or dirt accumulation.

No, natural ventilation on its own is not enough to handle the corrosive environment of water treatment plants, as toxic gases, high humidity and condensation can make corrosion happen faster. 

To effectively handle the harsher environment, natural ventilation in a water treatment plant needs to be designed with corrosion-resistant materials and complemented by a mechanical system made of equally resistant materials. In most cases, a hybrid system combining natural and mechanical elements is the best solution.