By Rory O’Malley – Hydraulic Principal.

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A couple of weeks ago our hydraulic services team and the Sundale Garden Village project were awarded the 2019 Plumbing & Gas Industry Awards Hydraulic Consultant Design of the Year award. One of the main reasons we won came down to the innovation we applied to the hydraulic design that helped Sundale to ‘kick some seriously green goals’.

How did we achieve this without breaking the bank?

From our past experience, ecologically sustainable developments and green building design initiatives are still seen as costly to projects and can often become nothing more than a ‘tick box exercise’ while the focus remains on cost driven decisions. Considering in the early conceptual stage how the building can efficiently function following final completion is typically overlooked – we’re more concerned about just getting the development built to minimum compliance standards. 

But projects like Sundale Garden Village are proof that we can take our responsibilities to sustainable design seriously, just as we should – after all, we all have a responsibility for limiting our environmental impact both at work and at home. And what if these practices are actually MORE cost effective, and can save you and your client time?

How is this possible?

From my experience on Sundale Garden Village and other projects, there are four elements of the hydraulic design to focus to help achieve your green goals cost-effectively.

1. Rainwater Harvesting & Re-Use

The way water should be used today and in the future is a full circle.

What do I mean by that? Water is produced from a source like the sky or dam and sent to a building. From the building we can reuse the water back into the environment, which in turn replenishes the water source.

Source: https://www.aypotech.com/blog/the-new-construction-goal-net-zero

Unfortunately, most of the time the building takes more than it’s giving back and drains the source, making it harder for the building to use the source again…which is what I mean by full circle.

So how do we ensure the circle is fully replenished?

• If planned correctly, capturing all the rainwater that drops on the site throughout a full calendar year and then reusing it pays for itself in the lifecycle of the building without taking up real estate. Determining where rainwater can be captured and treated has to be discussed at the beginning of a development.
• Set water conservation targets at the early planning stage e.g. target 20% less water use than standard practice. If a standard is set from the start of the project, its much easier for the design team to work out innovative ways to help achieve the target.
• Finding simple applications for rainwater reuse by looking at the:
  • watering demand of the development’s planting arrangement.
  • number a toilets throughout the site.
  • large plant equipment washdown requirements.

The team working on Sundale’s Garden Village community living project certainly had the foresight to focus on rainwater re-use. The development is within the Noosa Shire Council region, an existing sub-tropical rainforest, and backs onto Wooroi Creek, so the landscape design of the site was focused on retaining the existing natural feel and large subtropical planting arrangement. Keeping these plants alive in such a large development could potentially be large strain on any water source. To prevent this, the hydraulic stormwater design captured 100% of the roof catchment into inground rainwater storage tanks.  Hidden from sight by basement structural elements, the tanks sufficiently supply reticulated irrigation to each stage of the site in addition to supplying water for toilet flushing. This has ensured that the landscaping is self-sustainable and isn’t reliant on costly towns main water supply.

When it rains in Queensland…… it pours! Our designs should focus on capturing as much free water as possible. Likewise, we can go for long periods without water, like what is happening currently in Stanthorpe. Having a robust, year-round rainwater harvesting system is becoming more and more critical to building owners who want to reduce this risk.

2. Building Monitoring Systems

Building monitoring systems provide facilities with useful information, test results and outlet data to help ensure the buildings are running as efficiently as possible. This helps with forward planning, and also enables operators to understand how and when a fault is about to occur on a service – prioritising the maintenance team into action onto a potential costly issue.

For example, if a rainwater tank is being drained below 25% capacity and doesn’t have enough water to support the irrigation system during a winter month, a temporary top-up from the towns mains might be required. Understanding that this is happening means the building owners can plan ahead and look into larger storage or divert some extra reusable water within the site, reducing the likelihood of needing to access costly towns mains water in the future.

The more monitored real time data we have on a system, the more the system can become cost effective to all stakeholders. 

3. Plumbing Fixtures and Water Flow/Pressure

Choosing water efficient fittings and fixtures is now a base standard for developments that are looking to reduce their impact on the environment. But what about water flow?

The perception by some developers that water efficient fixtures result in annoyingly low pressure to the end user is a myth. Pressure and flow are different outputs – pressure to the end user is controlled outside of the fixture, e.g. it comes from the street or the base build system. Reducing the output flow (density of water) to save on the amount of water use doesn’t impact the end user if the water pressure is high enough.

So what fixtures should you choose to maximise pressure if you are conserving flow? Most plumbing fixture manufacturers are conscious of keeping operational water flows as low as possible without compromising the main function of the fixture. But the final decision is still on us as to ensure we are selecting or recommending the most water efficient unit available. A good environmental rule of thumb target is to check the fixture uses less than 6 litres of water per minute for any bathroom, laundry or kitchen unit.     

4. Construction Materials

Another simple way of ensuring the environment is impacted as little as possible is through the specification of construction materials that meet suitable environmental reduction targets. The national Enviro Development sustainability program outlines some minimum targets for hydraulic systems that can be brought across all types of developments such as:

• 25% of the total cost of PVC content is reduced through replacement with alternative materials.
• PVC content is sourced from an ISO 14001 certified supplier.
• the use of concrete pipes with >30% supplementary cement materials or >30% of recycled aggregate.
• the use of recycled plastic piping.
• the use of recycled copper & plastic fittings and pipework.

Key Takeaways:

To maximise the sustainability of the hydraulics design on your next project, I recommend you:

1. At the beginning of a development, determining where rainwater can be captured and treated, and identify all opportunities for re-use.
2. Use a building monitoring system to continually monitor and test systems to learn and improve future efficiencies.
3. When selecting your plumbing fixtures, check the fixture uses less than 6 litres of water per minute for any bathroom, laundry or kitchen unit.
4. Use the National Enviro Development sustainability program to identify the minimum targets for hydraulic systems.

To find out more about the sustainability design initiatives we’ve being using recently on projects such as Sundale Garden Village, or to discuss ideas for your next project, get in touch with me at rory.omalley@dmaengineers.com.au

 

References & Further Reading:

http://envirodevelopment.com.au/

http://www.yourhome.gov.au/water/rainwater