Watercare wastewater treatment plants are built to run for decades, so the access built into them on day one has to work just as hard as the plant itself.
On a new-build Watercare treatment plant serving South Auckland, including the Drury area and further north, main contractor Brian Perry Construction (BPC) needed permanent access built into the site as part of the original construction scope. That meant giving plant operators safe, compliant access to the pipework, valves, and processing tanks they would need to maintain for years to come.
SafeSmart Access was brought onto the project to design, manufacture, and supply that access.
WHAT WAS INSTALLED
The scope covered several types of custom access platforms and systems across the site:
- Stepovers, used to move people safely around the site and over pipework and other obstacles
- Access stairs, giving operators a way up onto the processing tanks to reach the valves and equipment that need ongoing maintenance and replacement
- Modular aluminium platforms, installed within a large underground overflow chamber designed to catch tank overflow. These platforms are fully removable, allowing access into the chamber when needed
DESIGNED AROUND FLETCHER’S CONSTRUCTION MODELS
Because this was a new build rather than a retrofit, SafeSmart didn’t need to 3D scan the site. Instead, the design team worked directly from Fletcher’s construction models and IFC drawings, developing the platform designs around the existing model and sharing STEP files back so the access systems could be incorporated into the overall construction model.
That coordination between Fletcher’s designers, SafeSmart’s design team, and the project engineers ensured every platform was purpose-built to the correct heights, with no clashes against cable trays, pipework, or other plant.
The site sits in a valley, which meant designing for high wind loads. SafeSmart addressed this by using proprietary high-capacity aluminium extrusions on the affected structures rather than changing the overall design approach.
why aluminium over steel
Engineers default to steel because it’s familiar. Getting aluminium approved for this job meant working closely with the project’s engineers early on to demonstrate it as a genuine like-for-like alternative, rather than asking the contractor to swap materials after the design was already locked in.
The case for aluminium came down to a few measurable advantages:
- Around 45% lighter than steel, making it easier to transport to site, easier to lift into place, and lighter on the loads placed on the slabs it was installed on
- Lower lifecycle and maintenance costs. Galvanised steel begins corroding as soon as the coating chips, and that damage compounds over the structure’s life. Marine-grade aluminium carries a significantly lower risk
- Marine-grade T6 6061 aluminium was used to meet the project’s corrosion-resistance and design-life requirements, which called for a 30-year design life, and it meets Watercare’s own material standards for contractors working on their sites
The weight difference also changed the install itself. A lighter structure meant less lifting plant required on site, and because SafeSmart’s platforms and stairs are supplied as fully welded, finished systems rather than raw extrusion assembled on site, installation was largely a case of lifting each piece into place, bolting it down, and fitting handrails.
the result
BPC and Watercare have both given positive feedback on the finished platforms. On a recent site visit roughly four years after installation, the systems were confirmed to still be performing exactly as intended, with no issues reported.
Without the stairs installed, operators would have no way to safely reach the top of the tanks to carry out maintenance, making this access a functional requirement for the plant’s day-to-day operation, not an add-on.Â
TALK TO SAFESMART ABOUT ACCESS FOR YOUR NEXT PROJECT
SafeSmart designs and manufactures custom access platforms, stairs, and stepovers for water treatment plants and industrial sites across New Zealand, working directly from client and contractor CAD models where required to make sure access is designed in from the start.
Get in touch with the SafeSmart team to talk through access requirements for your next project.
FREQUENTLY ASKED QUESTIONS
Why did SafeSmart use aluminium instead of steel for this project?
Aluminium offered a lighter, longer-lasting alternative to the galvanised steel engineers traditionally default to. At roughly 45% lighter than steel, it was easier to transport and install, placed less load on the site’s slabs, and avoided the ongoing corrosion risk that comes with a galvanised coating chipping over time.
How much lighter is aluminium than steel for access platforms?
On this project, the aluminium structures were approximately 45% lighter than an equivalent steel build. That weight saving reduced the lifting plant required on site and lowered the load placed on the surrounding structure.
What grade of aluminium was used?
SafeSmart used marine-grade T6 6061 aluminium, selected to meet the project’s corrosion-resistance and 30-year design-life requirements, and to align with Watercare’s own material standards for contractors.
Does aluminium cost more than steel?
Not always. Engineers often default to steel because it’s familiar, but aluminium can be commercially competitive, and on some SafeSmart projects, the aluminium proposal has come in cheaper than steel from the outset.
How long does installation take?
Because SafeSmart’s platforms and stairs are supplied as fully welded, finished systems rather than delivered as lengths of extrusion for cutting to size and screw/bolt assembly, installation is generally a case of lifting each piece into place, bolting it down, and fitting handrails, reducing on-site labour compared with a build-from-scratch steel structure.
