Which flush is which? Dual-flush fixtures should be better at making it obvious.
Editor's note: Thanks to Evan Dick for this guest post. Evan is a former writer from BuildingGreen and now works at the Center for EcoTechnology in Massachusetts.
The adage "If it's yellow let it mellow, if it's brown flush it down" might be an acceptable water-saving solution in some households, but certainly doesn't meet our expectations for cleanliness in more public throne rooms. Enter the dual-flush toilet, invented in 1980 by Bruce Thompson, an Australian working for bathroom products company Caroma. Dual-flush toilets have a full-flush option for solids and a partial-flush option for liquids. Each flush represents a measured and appropriate response to the waste-removal needs of the moment.
Unfortunately, flush controls on some models make it difficult to know which flush is which. Most of these toilets are in more public facilities, and getting busy, distracted people to understand and use the green design features we implement is a tricky problem, as we discussed in our recent feature on occupant engagement.
Confusing instructions
I used to get regular treatments from a Community Acupuncture Clinic in Tucson, Arizona. Not wanting to be distracted during my treatment, I almost always used their restroom. The toilet was equipped with a perplexing dual-flush handle, and no instructions except a circle split down the middle, with one semicircle fully filled in and the other semicircle halfway filled in. This circle was located at the pivot point of the handle.
I was never sure which flush I was choosing. Other models I have seen come with arrows or with stickers that can be placed on the tank to add further instruction.
SUPPORT INDEPENDENT SUSTAINABILITY REPORTING
BuildingGreen relies on our premium members, not on advertisers. Help make our work possible.
Another type of lever uses a dual-action approach, where the main lever has a smaller lever within it that moves separately. The small lever moves independently for the half flush, and the large lever activates the full flush. However, because moving the large lever will also move the small lever, users can also find this confusing.
Pushing my buttons
While levers are common for dual-flush conversion kits, new dual-flush toilets are usually equipped with a push-button system. While these shiny chrome circles divided into two buttons look nice, they too fail the clarity-of-use test.
One side is usually larger than the other, representing the larger flush, but the size difference is slight enough that further instruction is often required. Some systems use equal-sized buttons with decals identifying which side is which. This is adequate, but could be problematic if the decals come off and are not replaced.
The most straightforward button system consists of two separate buttons, each manufactured with a full or half-full circle to direct the user.
Potty training needed?
Maybe other folks are better potty-trained than I am, but an informal office survey found that other BuildingGreen employees had experienced similar confusion, with both the handle- and the button-controlled varieties.
The handles and buttons used for dual-flush toilets do important work and save water. That water savings should not be compromised by confusing design. If you have one of these toilets, simply adding an instructional sign, or making sure that markings on the controls are clear and well maintained should be enough to direct users to the right flush.
Looking for guidance on the most efficient dual-flush and regular-flush toilets? GreenSpec's listings of commercial toilets go a step beyond minimum federal standards, both in water efficiency and flushing performance.
(2012, February 16). Dual-Flush Toilets Shouldn't Be a Crapshoot. Retrieved from https://www.buildinggreen.com/blog/dual-flush-toilets-shouldnt-be-crapshoot
Commercial Dual Flush Toilets that are automatic tend to work better than the manual versions at saving water. The sensors detect based on time usage whether to flush for liquid or solid waste. The manual dual flush handles, which usually include a placard giving instructions on how to flush the toilet usually go unnoticed by the user, but the automatic model takes care of this problem.
Air Delights is a leading distributor of automatic flushers including the dual flush. Even have a solar powered automatic dual flush for toilets that saves energy as well as water. Visit airdelights.com for more information.
Thanks for telling me what I always guessed.... that a man invented this. I say this because of my experience with these in public restrooms. Down for #2, up for #1. Only a man who only sits down in a public restroom would make the "default" position the one of more water. If a women were to design this, they would realize that the majority of the time the less water option would be the default position.
I've been curious about how much water dual-flush toilets use compared to a conventional water-efficient toilet so I'm conducting my own experiment. In a 138-unit apartment building that I finished last March, I put a 1.28 gpf Toto on 4 floors of the building and put a 0.8/1.6 dual flush on the other floor. We submeter the apartments so we can track the water use. So far, the dual-flush floor isn't doing as well, but it is way too soon to draw conclusions.
(We picked all of the fixtures carefully. For the first 5 months, we're averaging 23.5 gallons per person per day for water use in the apartments.)
why use dual flush toilets when you can save 50% water "every" time with Niagara Stealth toilets?
And we got ours for just about $300.
My office LEED project has had one for a year and it is very quiet and flushes well every time and saves water every flush and no one has to wonder which button to press.
It's true that this isn't rocket science, but it is also true that many examples of industrial design have gotten more obscure in the last thirty years. Universal symbols tend to be equally obscure for every culture and language. Plenty of research has been done on icon recognition, and the choice of symbols makes a big difference, along with location, separation, and contrast. Yet industrial designers often ignore the research, and make buttons small, similar, and placed next to each other.
Overwhelmingly, research shows that people recognize icons plus words better than icons alone. Again, many designers seem to hate words. And with toilets, they seem to fear that the person using the toilet will somehow be offended if words give a hint on what a toilet is used for. Three dots? A half circle? Using devices shouldn't be a cryptology exam.
It's time we stopped blaming the users, and started demanding better design and labeling.
Seriously, these toilets have been in use for years in Europe and South East Asia. This just isn't rocket science. Take a moment to process the image presented and it's easy to figure out.
I totally agree. The first time I went to New Zealand I was as baffled as you are describing. There should be an easy fix to this especially if manufacturers are looking to get more consumer buy-in.
Add new comment
To post a comment, you need to register for a BuildingGreen Basic membership (free) or login to your existing profile.