David Davis of MEP engineer G&H says that with BREEAM remaining a well-used method for assessing sustainability goals, choosing the right product choices for earning points needs to be a prority, and why toilets are a key component.
Achieving higher levels of BREEAM rating can prove to be challenging and expensive, but additional points can often be earned by specifying water efficient toilet systems, which can significantly contribute to a building’s overall sustainability performance.
The Building Research Establishment Environmental Assessment Method, better known as BREEAM, is now a key go-to framework that provides a sustainability assessment for building and infrastructure in new builds, refurbishments, and fit-outs.
The certification allows for a consistent and comparable view across the entire built environment lifecycle, with ratings ranging from ‘Acceptable’ through to ‘Outstanding.’
Embedding this framework in the build process over the past 35 years has been highly effective, ensuring that architects seek additional BREEAM points where possible to improve building ratings. Achieving an ‘Acceptable’ status is relatively easy to obtain, but striving for ‘Outstanding’ requires a change in habits and can be expensive.
The BREEAM Wat 01 calculation considers ‘Water Consumption,’ focusing on reducing the demand for potable (drinking) water through the provision of efficient sanitary fittings, rainwater collection, and water recycling schemes. BREEAM Wat 01 Water Consumption credits are based on percentage improvement over baseline building water consumption.
A 12.5% improvement earns one credit, and the range increases up to six credits for a 65% improvement. For toilets specifically, refer to the table below from the BREEAM UK New Construction Technical Manual (SD5079, version 6.1). This manual contains all the relevant credit calculators.
Specifying some of the new washroom innovations can therefore help increase the score by up to six points, and it doesn’t have to be expensive. Let’s look at the options.
Most toilets are now available with a low flush or dual flush cistern, capable of flushing a toilet using less than six litres of mains water. Most dual flush toilets offer a 6/4 litre flush, some go down to a 4/2.6 litre flush. Most sanitaryware manufacturers list the performance of their products on the Unified Water Label (UWLA) website, offering an easy reference guide for specifiers.
BREEAM encourages sustainable water use in the operation of a building over its lifetime, so be aware that while many claim to save on a six litre flush, best practice is to monitor that they deliver that performance.
The BREEAM technical manual assumes one full flush for every three reduced flushes on non-domestic buildings as part of the calculation for water conservation. However, research has shown that many users don’t understand the purpose of the two buttons on a dual flush toilet, and some public toilets attempt to ‘educate’ users with signs suggesting that both buttons should be used to flush the toilet, thereby defeating the initial promise.
Direct flushing toilets, which don’t require a cistern, are another option. Designed to suit highly frequented public toilets, this option is more expensive but, having brass valve components, can offer lower maintenance costs.
While they are available as a 6/3 litre dual flush, saving water, they are also designed to reduce the risk of leaks, another sustainable advantage. Such direct flushing toilets however require a wider diameter water outlet, so tend to be the preserve of new builds or major renovations, not for retrofit.
Under BREEAM assessments, specific toilets, such as vacuum toilets, claim to reduce water consumption by 85%, with flushing usage of around 1-1.5 litres. They are a solution with some compelling benefits, and there is no doubt about their water saving performance and ‘close to flush’ hygiene benefits.
But again, the positives in BREEAM points achieved need to be balanced with a higher unit cost, a need for a dedicated water supply, extra space for equipment, and lastly, an electrical power supply.
A more recent innovation we have been using (eco-cistem) seems to offer many advantages. It is a component of the toilet, rather than a complete system, so it can be paired with any brand of sanitaryware.
The toilet cistern uses the waste condensate water created by the building’s air conditioning units to flush the toilet. It can therefore only deliver its fresh water saving benefits if paired with an air con unit within the building. However, BREEAM points can be gained from specifying it not only due to its reduced flush volume, but also because it uses a grey water source, both of which factor into the credit calculation. Exact amounts of grey water used within its installation can also be easily monitored.
This toilet cistern has an 18 litre twin chamber cistern that can store up to 12 litres of free condensate water above a standard six litre chamber dedicated to flushing the toilet.
The unit prioritises using the grey water for flushing and only pulls in fresh water when no condensate water is available, therefore ensuring an efficient flush each time with no reduction in performance if the aircon system is not in use. The installation requires that the pipework, which drains away the condensate from the aircon unit, be diverted to go into the cistern instead of straight into the waste pipe, which in most cases is a very simple diversion to plan.
The amount of condensate produced by air conditioning units will vary based on usage by country. However, even in the UK, the forecast for air conditioning unit sales is dramatically on the increase and considering a small 1.75 kW air con unit can produce over a litre of water per hour, installation will always make a substantial saving on freshwater usage.
Monitors in two hotel installations in Europe have demonstrated 64% peak water savings, making them eligible for BREEAM points under WAT 01 and earning up to six points in the LEED water efficiency category. There is a slight increase in cost to use this cistern option, so that also needs to be taken into account.
When looking at which toilet system is right for your next project, it is vital for architects to consider whether or not it contributes to increasing your building’s BREEAM rating.
David Davis is a director at MEP engineering firm G&H