Business, industry and planning guidance

Stacks guidance sheet


This guidance sheet forms part of a series of guidance sheets on preventing and managing offensive odours, and should be read in conjunction with EPA Victoria’s Odour Guidance for Industry webpage. 

Odour stack good dispersion

Odour stack bad dispersion
Figure 1: How stack height results in good odour dispersion (top), and poor odour dispersion (bottom).

Description

A stack is a type of chimney used to exhaust gases into the outside air. Stacks work by releasing gases high and fast enough so that odour emissions are widely dispersed. This means odours are less likely to impact on nearby sensitive receptors. Gas emissions may require treatment with other odour prevention methods before they are exhausted through a stack.

Type of control

Physical.

When you would use this?

If your business generates odorous gases, then a stack is a recommended way to release these treated gases into the outside air.

Suitable for: any gaseous odours.

Industries that would use this: any industry that treats or produces odorous gases could benefit from a stack.

Details and considerations

While a stack is a very useful piece of engineering, there are several considerations to keep in mind when deciding if a stack is right for you:

  • Stacks do not actually eliminate any odour, they simply disperse it widely enough to dilute the odour so that it is less detectable, or not detectable at all, by sensitive receptors. When installing a stack, coupling it  with other odour prevention methods is recommended.
  • There are certain requirements when building and installing a stack to ensure it fulfils its purpose (see Further information). Getting this right will mean consulting a contractor or engineer for design and/or installation.
  • Ensure your stack/s adhere to council planning permissions, especially for smaller businesses.

For effect odour reduction, it is important to ensure your stack meets the following requirements:

  • It is structurally sound, well designed and properly installed. You may need to engage appropriate contractors for this.
  • Stack design should consider the local meteorological conditions.
  • Depending on your operation, you may need more than one stack.
  • A contractor can undertake air modelling to ensure optimum design to meet the State Environment Protection Policy (Air Quality Management) design criteria.
  • The exhaust exits your site from a vertical, open topped, stack.
  • The stack is a minimum of 3 metres taller than any other structure within a 20 metre radius of the stack (this is important for odour dispersion).
  • The stack emits exhaust at a speed of at least 10 metres per second (this is important for odour dispersion). Achieving this will require the installation of a stack with the correct diameter and fan running at the correct speed.

    Further information

     For more comprehensive information on stacks see relevant Australian standards:

    Australian Standard  Title 
    AS4323  Stationary source emissions selection of sampling positions 

    Page last updated on 4 Jun 2019