Drainage (& Trade Waste)

The drainage systems within school facilities includes all the associated pipework and services for the removal and disposal of sanitary drainage and stormwater management in two separated systems.

The drainage services is to be designed from a “Whole of Life” (WOL) perspective to provide:

• Value for Money
• fit for purpose
• long term reliability
• minimal maintenance requirements
• low maintenance costs

Refer to DG / WHOLE OF LIFE

The design of the drainage system is to meet the relevant Statutory requirements, and address the following issues:

• Fully comply with the requirements of AS3500, Plumbing Code of Australia and the Building Code of Australia and any other relevant statutory requirements.
• Fully comply with the requirements of the local water or supply authority.
• Support sustainable design principles including reducing water consumption and waste production.
• Appropriately treat any trade waste to ensure minimal environmental impact.
• Be accessible and serviceable - easy to maintain with minimal impact on school use when maintenance is being performed.
• Use products with a long life span – many hydraulic services are concealed so durability is essential.
• Use pumps for disposal of effluent where there are no other options. 
• Comply with the requirements of the Geotechnical Report.
• Keep branch lines as short as possible.
• All pipe work to be accessible for cleaning with flexible rods. Where located below paved or bitumen areas, clear outs are to be extended to finished surface level and terminate with vandal proof brass cover.
• All underground drainage systems within the site area are to be CCTV inspected after installation and submitted as part of the work as executed submission.
• Avoid running pipework on wall surfaces.  When there is no acceptable alternative, run pipes in minor rooms, and boxed in.
• Maximise vandal resistance of all installed pipe work.
• Stacks and vertical pipework to be concealed wherever possible.  Ensure unhindered access is available.
• Stacks are to have cleaning access at each level and provide access panels at cleanout points.

GUIDE NOTE: Refer to NATSPEC 0822 Wastewater for changes of gradient and changes of direction of stormwater drains.

• Access chambers shall be of pre-cast concrete or cast insitu concrete complete with lid.
• Pit lids shall enable lifting by specialist equipment and be compliant with OH&S requirements.
• Provide an easily removed, square of concrete separated from the main slab, marked to indicate the intersection point of branch lines under pavements etc. 

• All chemicals used in schools must comply with the Chemical Safety in Schools policy; this limits chemical quantities used and has strict requirements on how they may be disposed.
• Main acids used in schools are received in the following concentrations:

            Hydrochloric       32%

            Sulphuric           98%

            Nitric                 70%

• Dilution: generally to 5-10% (1 or 2 molar concentrations) for use in laboratory experiments.
• Usage: approximately 500-1000ml per practical period up to 20 times per year for each laboratory (varies from school to school).
• Dilution pits are required by all relevant authorities for all science laboratories.

Waste Disposal from Science Sinks

• Waste Systems shall be acid-resisting
• Position dilution pit between the acid-resisting branch line and main sewer
• Calculate size based on 14 litres per single or double water point throughout

• High school art rooms require a plaster arrestor.
• Primary schools do not require plaster arrestors.
• Clays used in schools:

Terra-cotta                         80%

Stoneware                        20%

• Terra-cotta clays contain:

Iron (oxides)                     6%

Aluminium silicates           80%

Non toxic pigments          variable

Where provided activities within the Dark Room involve film processing.

• Used irregularly by art, industrial arts and science classes. 
• Waste solutions will have been diluted first for use and again on disposal. 

The two most common chemicals will be:

Fixer                 Boric acid                     - diluted for use 1-4

Developer          Bromide developer         - diluted for use 1-8

• It is unlikely that more than 2-3 litres of diluted chemicals would be disposed of in a week.
• Dilution pit is required.