There are a number of outrageous claims on the web about potential savings from using waterless urinals. As the true savings are usually significant, Gentworks perceives no need to artificially inflate them.  If you assume an average urinal is flushed with 4.5 litres every 5 minutes, then the potential savings from waterless urinals are truly immense. However, such urinals breach current water regulations and represent the extreme, rather than the average. Below are some realistic examples of costs incurred and savings made, based upon surveys conducted by Gentworks at sites that subsequently converted to waterless. The data gathered about each site has been entered into the same spreadsheet as available via the link below.

 

Example 1: Small office building in London - 6 urinals with visible traps

Example 2: Larger office building in Oxfordshire - 34 urinals with mostly concealed traps (higher installation costs)

Example 3: Factory in Shropshire - 22 urinals, mix of trap types

 

To calculate, with reasonable accuracy, the potential savings from waterless urinals at your site, you will need to enter some key data into the spreadsheet.  This can be opened by clicking on the icon below. Note that the spreadsheet will open in a separate window so you may need to give permission for a 'pop-up', should your browsing software request it. If you have any comments about the spreadsheet, or would like some advice or help to complete it , please call 0845 202 4535 or email support@gentworks.co.uk . We always welcome the opportunity to talk through the issues. 

 

 

    Costs and Savings Calculator  (306k Microsoft Excel 2000 file)   

 

 

how waterless urinals work

converting urinals to waterless

waterless urinals pros and cons

 

If you are considering the option of Gentworks engineers installing and/or servicing the waterless urinals, then click here for more information about what we do.

Once completed, the spreadsheet presents the following results:

 

Collecting Data on Current Urinal Water Usage

The most accurate way to assess the amount of water being used to flush urinals is to fit a water meter on the pipe that supplies water to the urinal cistern(s). In the absence of a water meter, a reasonable assessment can be made by multiplying the capacity of each cistern by the number of flushes that occur over a 'normal working week'. Of course, such an exercise would be very time consuming unless an electronic flush controller with an audit facility is fitted, and these are rare. Counting flushes by sitting in the washroom all day for 7 days is not a realistic or attractive option for most people.

Gentworks has surveyed several thousand washrooms over the last 7 years. Based upon our experience, our spreadsheet incorporates some assumptions for the frequency of flushing for urinals with and without flush controllers. For ease of use, the spreadsheet assumptions are generic, but the cells can be overwritten with more accurate data gathered from your washrooms.

In the absence of a water meter or sophisticated flush controller, the best way to assess ‘flush frequency’ is to count the number of flushes that occur in 1 hour. If an hour cannot be spared for this exercise, then time the period between one the beginning of one flush starting and the next. Use this reading to calculate how many flushes an hour this indicates. In washrooms where no flush controller is fitted, the result should be reasonably representative of every hour, every day.

Flush controllers are fitted in many washrooms and are now a requirement of water regulations. During site visits, Gentworks engineers find that around 20% of flush controllers installed are not operating correctly or have been disabled. Therefore, the presence of a "box on the wall" does not necessarily indicate that flushing is truly being controlled. Generally, if you can hear water flowing into the cistern for longer than 10 minutes, even though nobody is activating the controller via the sensor or other means, then the likelihood is that the controller is not working correctly, if at all. Notable exceptions are the Cistermiser EIRC and IRC2 sensor controllers which are designed to fill the cistern for a period of 30 minutes after sensor activation.

If a flush controller is working correctly, it will be saving a great deal of water. The downside is that  maintenance costs are likely to be higher because blockages can become more frequent. A urinal that flushes every 5 minutes is umlikely to block, whereas long periods between flushes allows limescale, uric acid salts and debris to combine and coat the inside of the waste pipes. Therefore a balance between water usage and maintenance expenditure needs to be achieved. Unless waterless or  low flushing systems are installed, Gentworks recommends that urinals should be flushed within 20 minutes of use and every 12 hours when not in use.