Fumehood plumbing

Fumehood plumbing. We are about to install a fumehood and the question has come up about its plumbing. Can it be plumbed into the normal waste water / sewer lines or is something else needed? Not sure why it should be any different from a normal sink, neither sink is for disposal of toxic chemicals?

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Publication Date: 22 October 2015
Asked By: dgauntlett
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Fumehood plumbing

In brief:

There are several points to consider in answering this question as fume cupboard installation involves different authorities and regulatory bodies such as local water authorities, and compliance with a number of Australian Standards. Regulatory body advice and Australian Standards are not prescriptive due to the numerous different settings. Your school should ensure that the builder installing the fume cupboard is familiar with the regulatory requirements of their state/territory and the relevant Australian Standards. The following should be consulted.

  • The local water authority for specific waste water requirements for your jurisdiction, such as the requirement for dilution pits prior to discharge to sewer.
  • AS/NZS 3500:2015 Plumbing and drainage Parts 1 and 2 for all in-house requirements, such as backflow protection of the water supply and other special requirements for plumbing of the waste connections.
  • AS/NZS 2982-2010 Laboratory design and construction for general information.
  • AS/NZS 2243.8 2014 Safety in laboratories Part 8: Fume cupboards for all aspects of fume cupboard installation compliance.

Science ASSIST recommends the following.

  • Fume cupboard waste plumbing be kept separate from all other sink and floor waste plumbing in the laboratory and preparation areas. This is to minimise the risk of any fumes entering other areas of the laboratory through the bench sinks or floor wastes.
  • Water authority guidelines are followed regarding chemical waste disposal. The usual precautions apply for substances that should not be disposed of down the sink, for example heavy metal salts and organic solvents.  These should be retained for waste chemical collection. 

Note: Science ASSIST has developed resources on the following (Answer updated 18 June 2018):

Additional information

Ducted fume cupboards are widely used in school science laboratories to protect the operator and other personnel in the laboratory from hazardous fumes and particles. They operate on a fan system that intakes air to dilute hazardous fumes or particles and exhausts them to a safe area outside of the building though a duct system. Fume cupboards also normally contain a sink with a drain to allow certain substances to be disposed of to the sewer.

Local Water authorities in each state/territory may have specific requirements for the pre-treatment of waste water before discharge to sewer. Fume cupboard sink drains, as with all laboratory sink drains, may also need to connect to an acid dilution or neutralization pit, as required by the appropriate regulatory authority.

AS/NZS 2243.8: 2014, Safety in laboratories: Fume cupboards states:

Section 2 Types, Services and Components, 2.4 Sink

Any sink fitted to a fume cupboard needs to comply with relevant local water authority requirements.

NOTE: AS/NZS 2982.1 specifies requirements for laboratory water services, including disposal systems.” 1

Plumbers are responsible for the in-house connections of the plumbing and need to follow the AS/NZS 3500 series on Plumbing and drainage standards.

Part 1 contains instructions for specification to avoid cross connections and backflow protection in relation to the water supply. Certain facilities such as secondary school science laboratories have the potential to encounter cross connections between the water service and some laboratory equipment such as fume cupboards. Devices for this may need to be put into place.

Part 2 contains instructions regarding laboratory sinks and drains. This specifies the requirements for laboratory sinks connections such as using a trap, the size of the waste pipe and also not connecting sinks as fixture pairs.

AS/NZS 2982-2010 Laboratory Design and construction refers to the planning and design stage, which includes consideration of siting and the provision of reticulated services, including liquid disposal to maximise safety in regard to fume cupboard installation. It also makes reference to the location of dilution pits and vents if required for the liquid waste disposal system.

AS/NZS 2982: 2010 Laboratory design and construction states:

Section 3 Reticulated Services, 3.9.5 Disposal of liquid waste

Dilution pits and vents in the liquid waste disposal system shall be located at least 6m away from mechanical ventilation outdoor air intakes.

Note: Equipment for liquid waste is required to comply with the regulations of the sewerage authority”.2

AS/NZS 2243.8:2014 Safety in laboratories Part 8: Fume cupboards contains information on the safety, performance, installation, testing and use requirements for fume cupboards. It also has further specific instructions for fume cupboards for specific applications, for example, in certain circumstances it is recommended that fume cupboard drainage does not combine with the floor waste prior to the floor trap waste. Science ASSIST considers that this would be considered best practice.

Science ASSIST has some related resources on fume cupboards:

Fume cupboard servicing

AIS: Recirculating fume cabinets


1 This excerpt from AS/NZS 2243.8: 2014, Safety in laboratories: Fume cupboards reproduced with permission from SAI Global Ltd under Licence 1407-c117

2 This excerpt from AS/NZS 2982.2010 Laboratory design and construction reproduced with permission from SAI Global Ltd under Licence 1407-c117

Standards Australia. 2014. AS/NZS 2243 Safety in Laboratories, Part 8: 2014 Fume cupboards. Sydney, Australia.

Standards Australia. 2010. AS/NZS 2982.2010 Laboratory design and construction. Sydney, Australia.

Standards Australia. 2015. AS/NZS 3500. 2015 Plumbing and drainage, Part 1: Water services. Sydney, Australia.

Standards Australia. 2015. AS/NZS 3500. 2015 Plumbing and drainage, Part 2: Sanitary plumbing and drainage. Sydney, Australia.

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