Implement urinal
flush controls
WTR03
Ineffective control of the urinal flushing cycles within your facility literally results in water going straight down the drain, easy to implement retrofit options exist.
Various countries have regulations stipulate that there should be a defined maximum water usage of circa 7.5 Litres per urinal bowl per hour and that a device should be fitted to prevent the urinals flushing when the building is unoccupied. However, in practice, flush rates are often adjusted, in an attempt to reduce odour or blockages, and flushing can continue for 24 hours a day, seven days a week. For some offices and buildings, this may mean that upwards of 75% of flushing occurs when the building is unoccupied. Urinals therefore often flush regardless of use, wasting a lot of water, especially out of hours.
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There are now various options of waterless urinals available in the marketplace, each with benefits and drawbacks, however this conservation measure will focus on measures that are simple to retrofit, without changing the urinal.
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Establishing the presence and effectiveness of any flush control to your urinals is the first required action, determined through observation and measurement calculate how often the urinals flush and what volume of water is used per flush. This data will allow you to determine the likely benefit in retrofitting appropriate measures.
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Retrofit options
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Passive infra-red motion sensing
A motion sensor is placed above the urinal to detect use. This controls a solenoid valve to allow a pre-set volume of water into the cistern per use. When the cistern is full, the auto-siphon will automatically discharge and flush. Again installation is inexpensive and can reduce water use by over 75%. A typical uncontrolled flushing of urinals is three times an hour, which with a 7.5 - 12 litre cistern will be using 197000 - 315000 Litres of water per year. In companies where the urinals operate without flush control, based on 100 male staff working 260 days a year, savings of over £3,800 per year in water and sewerage costs can be achieved by installing passive infrared sensors at a cost of around £350 - a payback of five weeks.
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Timer and solenoid valve
A timer and solenoid valve can be installed on the pipework connected to the urinals so that water supplied to the cisterns is shut off during periods when the facility is unoccupied. This option can reduce water use by over 75% is another low-cost option, but is only effective if work hours of the building users are predictable.
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Pressure sensitive hydraulic valve
A pressure sensitive hydraulic valve can be fitted to the inlet pipework of the urinal system and can reduce water use by over 75%. This is a retrofit option and the valve remains closed when pressure remains unchanged (i.e. when urinal is not being used). When the inlet water pressure temporarily decreases through water being used elsewhere in the washroom, the diaphragm-operated valve opens, allowing a pre-set amount of water to pass into the urinal cistern.
A disadvantage of this system is that flushing is related to occupancy of washrooms rather than use of urinal
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Conversion to waterless urinals
Two primary simple options exist:
Deodorizing pad
a pad impregnated with a deodorizing chemical is inserted into the urinal outlet. The major disadvantage with this is that the pads have to be replaced and disposed of every week, depending on use. This costs around £30 – 50 per urinal per year.
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Biological control
A cartridge containing a microbial stick is fitted into the urinal bowl or trough to break down urine and biofilm. The principal disadvantage to this system is that the stick dissolves and needs to be replaced 3 to 4 times a year, depending on use. It is also important that cleaning fluids used on the urinal are compatible with the microbial stick, incompatible cleaning agents can render the biological action ineffective resulting in odour and increased risk of blockages.