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Prison Breaks Considered When Designing Stormwater System at Milton Prison


In December 2004, Humes was successful in becoming the supplier of product for the “In-ground Services” for the new Department of Corrections Facility constructed in Milburn, South Otago.

The new facility was required to replace the 110 year old Dunedin Prison, which had well passed its use-by-date.

The medium security Corrections Facility is built on a 187 hectare site. The actual prison buildings – 30 in total, sit on approx 17 hectares (about 10% of the total site area) The site is secured by a 5.5 metre high fence made of a precast concrete wall that runs the perimeter – approx 1680 metres in length.

Fulton Hogan, one of the Collaborative Working Contractors assigned to the project, were the contractor for the in-ground services.

The project was to run to very tight lead times for product delivery and with the location being 60km out of Dunedin, careful planning by the Fulton Hogan construction team and Humes was paramount.

One of the unique aspects of working on this project, was of course that every design element took into account of the security and the elimination of any possible “prison break”. For the Stormwater discharge from the prison site a 750 diameter pipe would normally be required to handle the flow conditions – so Humes, Fulton Hogan and the Consultant developed a “Pipe Stack” of 225 diameter concrete pipe so that the volume of Stormwater could be carried away and there was no chance for any person to climb inside!

Clutha District Council stipulated that the products supplied to site met with the appropriate product standards. In particular the Watermain package had to be Standards Mark approved, manufactured to AS/NZS standards and tested to the Australasian Drinking Water Standard (AS 4020). Humes were well positioned to comply with the AVK water reticulation range – Valves, Hydrants, DI Fittings and Couplings.

The total supply of product to this one construction project can be likened to a similar volume of products that would be required for a medium sized subdivision! Over 11.7km of Sewer and Stormwater Pipe and 119 Precast Concrete Manholes!

For the project, Humes has supplied:

  • Precast Concrete Manhole systems: 119 Units
  • Precast Concrete Mudtanks (Cesspits): 106 units
  • Concrete Pipe ranging from 225mm to 750mm: 2.4km
  • uPVC Stormwater and Sewer Pipe: 11.7km
  • uPVC Fittings: 3750 units
  • AVK Fire Hydrants and Sluice valves: 126 units
  • AVK Supa Fittings and Ductile ron Fittings: 502 units
  • Cast Iron Streetware/Service Boxes: 437 units

This was no small project! At the peak of construction, the total work force on the site rose to 550 staff.


Hawkings Construction and Fulton Hogan Ltd.

Where & when:

Milton, South Otago - 2007

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7 February 2018