Tas Section H On-site waste water systems

This Part is an addition to Tas Part H1 and sets out the requirements for the connection of water flushed sanitary fixtures and sanitary appliances to an on-site wastewater management system other than a sewerage system. It also sets out the installation requirements for on-site wastewater management systems.

This Part sets out the requirements for how greywater is managed for domestic premises in Tasmania. It also sets out classification levels and methods of disposal for each of the three options.

This Part is an addition to Tas Part H2 and depicts low risk trade waste products and installations connected to an approved disposal system other than a sewerage system.

The low risk trade waste products and installations depicted below may be used if they are installed in accordance with the diagrams and notes shown.

Tas Figure H202.4a Typical silt pit

Notes:

1. The silt pit is to be connected as specified by the designer and authorised by the Permit Authority.
2. The bucket is to be constructed of mild steel plate, a minimum of 3 mm thick with 4 rows of 10 mm diameter holes at 25 mm centres. The bucket must be hot dip galvanised after fabrication.
3. Sizes shown are minimum permissible dimensions.
4. All dimensions shown are in millimetres.

Tas Figure H202.4b Typical silt trap

Notes:

1. The silt trap is to be connected as specified by the designer and authorised by the Permit Authority.
2. The bucket is to be constructed of mild steel plate, a minimum of 3 mm thick with 5 rows of 10 mm diameter holes at 25 mm centres. The bucket must be hot dip galvanised after fabrication.
3. Sizes shown are minimum permissible dimensions.
4. All dimensions shown are in millimetres.

Tas Figure H202.4c Typical straining pit

Notes:

1. The straining pit is to be connected as specified by the designer and authorised by the Permit Authority.
2. The basket is to be constructed of mild steel wire —a minimum of 2.5 mm in diameter —woven to give 7 mm aperture widths on a 32 x 32 x 3 mm angle iron frame with mitred corners. The top is to be welded from angle iron frame. The basket is to be hot dip galvanised after manufacture. Alternatively the basket may be constructed from mild steel plate a minimum of 3 mm thick with 6 mm diameter holes at 12 mm centres over the entire area of the basket. The basket is to be hot dip galvanised after manufacture.
3. All dimensions are in millimetres.

Tas Figure H202.4d Typical straining trap

Notes:

1. The straining trap is to be connected as specified by the designer and authorised by the Permit Authority.
2. The basket is to be constructed of mild steel wire — a minimum of 2.5 mm in diameter — woven to give 7 mm aperture widths on a 32 x 32 x 3 mm angle iron frame with mitred corners. The top is to be welded from angle iron frame.
3. The basket is to be hot dip galvanised after manufacture. Alternatively the basket may be constructed from mild steel plate, a minimum of 3 mm thick with 6 mm diameter holes at 12 mm centres over the entire area of the basket. The basket is to be hot dip galvanised after manufacture.
4. Straining traps to be used in installations connected to the Network Utility Operator's sewerage system must comply with the requirements of the Network Utility Operator's Guidelines for pre-treatment device requirements.
5. All dimensions are in millimetres.

Tas Figure H202.4e Typical grease interceptor appliance (for above or below ground installation)

Notes:

1. The capacity of the grease interceptor appliance below the outlet is to be as specified in the design and authorised by the Permit Authority. The capacity of the interceptor shown is 1080 L.
2. Where not specified, the capacity below the outlet is to be equivalent to the maximum hourly discharge provided that the minimum capacity below the outlet is at least 250 L.
3. As the contents of the unit may become slightly acidic, it is recommended that the internal concrete surfaces below outlet level be provided with an acidic resistant lining.
4. If installed above ground the grease interceptor appliance may be constructed using other authorised materials provided adequate structural support for the grease interceptor appliance is provided.
5. The grease interceptor appliance is to be located in a position so as to provide ready access for maintenance and inspection purposes.
6. Where a grease interceptor appliance is to be installed outside a building, consideration should be given to fitting airtight covers, venting the chamber and providing a screwed cap and DN 50 vent to the disconnector gully.
7. All dimensions are in millimetres.

Tas Figure H202.4f Typical portable grease interceptor appliance (for above ground installation)

Notes:

1. The capacity of the grease interceptor appliance below the outlet is to be as specified in the design and authorised by the Permit Authority. The capacity of the interceptor shown is 162 L.
2. Where not specified, the capacity below the outlet is to be equivalent to the maximum hourly discharge provided that the minimum capacity below the outlet is at least 100 L.
3. The interceptor and baffle is to be constructed of 6 mm unplasticised polyvinyl chloride (PVC-U); galvanised sheet steel with a minimum width of 0.79 mm; sheet copper or 316 grade stainless steel with a minimum width of 0.63 mm, all welded construction, or other authorised material.
4. Airtight cover(s) (using lever clips) to be provided to the grease interceptor appliance and the vent is to be extended to open air in accordance with clause 6.8.3 of AS/NZS 3500.2.
5. The grease interceptor appliance is to be located in a position so as to provide ready access for maintenance and inspection purposes.
6. If the grease interceptor appliance is to be installed externally it is to be protected from direct sunlight.
7. All dimensions are in millimetres.

Tas Figure H202.4g Venting of grease trap chambers

Tas Figure H202.4h Alternative (mechanical) venting of grease trap chambers

Tas Figure H202.4i Grease trap installation within multi-storey building

Tas Figure H202.4j Typical oil and petrol interceptor

Notes:

1. The capacity of the interceptor appliance below the outlet is to be as specified in the design and authorised by the Permit Authority. The capacity of the interceptor shown is 1140 L.
2. Where not specified the capacity below the outlet is to be at least 1140 L.
3. Airtight covers are required and are to be of a suitable size and be readily removable by one person. A 600 mm x 600 mm or 600 mm diameter cover is required over the inlet and outlet of the pit.
4. Where subject to traffic loadings, suitable covers capable of withstanding such loads are to be provided.
5. The vent is to be extended to the open air in accordance with clause 6.8.3 of AS/NZS 3500.2.
6. The DN 100 cast iron pipe outlet fitting is to be manufactured in one piece.
7. PVC-U shall not be used for the construction, connecting or venting of this unit.
8. This interceptor may accumulate quantities of explosive and/or flammable materials and therefore care is to be exercised in the maintenance and general use of the interceptor.
9. The interceptor is to be located in a position so as to provide ready access for maintenance and inspection purposes.
10. Oil and petrol interceptors and/or treatment devices connected to the Network Utility Operator's sewerage system must comply with the requirements of the Network Utility Operator's Guidelines for pre-treatment device requirements.
11. All dimensions are in millimetres.

Tas Figure H202.4k Typical acid neutralising tank

Notes:

1. The capacity of the tank below the invert level of the outlet pipe is to be as specified by the designer and authorised by the Permit Authority. The capacity of the tank shown above is the minimum requirement of 27 L between the marble chip level and the outlet level.
2. The tank and fixed baffles are to be constructed of unplasticised polyvinyl chloride (PVC-U) sheet with a minimum width of 6 mm; acid resistant stainless steel all welded construction with a minimum width of 0.63 mm; or other authorised acid and alkali resistant material and construction methods.
3. The diameter of the outlet pipe is to be at least one size larger than the inlet pipe (i.e. DN 65 inlet – DN 80 outlet). Where the diameter of the inlet pipe is DN 100, the diameter of the outlet may be DN 100.
4. The three baffles are to be equally spaced through the tank length.
5. The 32 x 32 x 25 mm deep PVC-U test block bracket is to be fitted as close as practicable to the outlet.
6. The 150 x 25 x 25 mm cement mortar test block is to be supplied and fitted to the satisfaction of the Permit Authority.
7. The size of the marble chips are to be within the range of 40 mm to 60 mm.
8. The tank is to be located in a position so as to provide ready access for the fitting of the cement mortar test block, obtaining samples from the sampling valve, replacement of the marble chips and for ongoing maintenance purposes.
9. Where the unit is to be located below ground level—
   1. The unit is to be surrounded with thick concrete walls and base with a minimum of 100 mm.
   2. The DN 25 sampling valve is to be omitted.
   3. The outlet level is to be no greater than 600 mm below surface level.
   4. The outlet pipe diameter is to be at least DN 100.
   5. The outlet is to be connected to a disconnector gully fitted with a loose fitting grate or screwed cap.
10. All dimensions are in millimetres.

Tas Figure H202.4l Typical mixing tank

Notes:

1. The capacity of the tank below the invert level of the outlet pipe is to be as specified by the designer and authorised by the Permit Authority. The capacity of the tank shown above is the minimum requirement of 100 L.
2. The tank and baffles are to be constructed of 6 mm min. unplasticised polyvinyl chloride (PVC-U) sheet; 0.63 mm min. acid resistant stainless steel all welded construction; or other authorised acid and alkali resistant material and construction methods.
3. The diameter of the outlet pipe is to be at least one size larger than the inlet pipe (i.e. DN 65 inlet – DN 80 outlet). Where the diameter of the inlet pipe is DN 100, the diameter of the outlet may be DN 100.
4. The three baffles are to be equally spaced through the tank length.
5. The 32 x 32 x 25 mm deep PVC-U test block bracket is to be fitted as close as practicable to the outlet.
6. The 150 x 25 x 25 mm cement mortar test block is to be supplied and fitted by the water authority's authorised officer.
7. Consideration should be given to the provision of adequate structural support for the tank.
8. The tank is to be located in a position so as to provide ready access for the fitting of the cement mortar test block, obtaining samples from the sampling valve, replacement of the marble chips and for ongoing maintenance purposes.
9. Where the unit is to located below ground level—
   1. The unit is to be surrounded with concrete walls and base, at least 100 mm thick.
   2. The DN 25 sampling valve is to be omitted.
   3. The outlet level is to be no greater than 600 mm below surface level.
   4. The outlet pipe diameter is to be not less than DN 100.
   5. The outlet is to be connected to a disconnector gully fitted with a loose-fitting grate or screwed cap.
10. All dimensions are in millimetres.

Tas Figure H202.4m Typical settling tank

Notes:

1. The capacity of the tank below the invert level of the outlet pipe is to be as specified by the designer and authorised by the Permit Authority. The capacity of the tank shown above is the minimum requirement of 72 L.
2. The tank and baffles are to be constructed of unplasticised polyvinyl chloride (PVC-U) sheet a minimum of 6 mm thick; galvanised steel sheet a minimum of 0.79 mm thick; a minimum width of 0.63 mm or 316 grade stainless steel all welded construction; or other authorised acid and alkali resistant material and construction methods.
3. The diameter of the outlet pipe is to be at least one size larger than the inlet pipe (i.e. DN 65 inlet – DN 80 outlet). Where the diameter of the inlet pipe is DN 100, the diameter of the outlet may be DN 100.
4. The tank is to be located in a position so as to provide ready access for obtaining samples from the sampling valve and for ongoing maintenance purposes.
5. Where the unit is to located below ground level:
   1. The unit is to be surrounded with 100 mm min. thick concrete walls and base.
   2. The DN 25 sampling valve is to be omitted.
   3. The outlet level is to be no greater than 600 mm below surface level.
   4. The outlet pipe diameter is to be not less than DN 100.
   5. The outlet is to be connected to a disconnector gully fitted with a loose-fitting grate or screwed cap.
6. All dimensions are in millimetres.