The Design

The Design Solution for P-Island

Waterfall-P-IslandDue to the difficulty of mathematically modelling such an irregular stream, our process has involved using qualitative understanding of the nature of splash and combining that knowledge with the numerical data and comparing it to a waterfall with stone splash at its base as depicted in nature.

Our solution is a series of curved, irregular nodules (peaks and troughs] resembling a bed of stone pebbles placed on a curved shape. By orientating them such that the leading edge is always tangent to the stream of urine we reduce splash as long as the leading edge and neighbouring peaks and troughs are of dissimilar heights (See Figure 4). And if the stream travels between stators (as it statistically most often will), we orientate the pebbles such that the stream never contacts the pebbles with a normal velocity above the splash threshold. Furthermore, because at some point the fluid will run off the smooth surface we will ensure that the fluid decelerates via friction sufficiently to prevent splash at that point. In this way, we near completely (80 – 90 %) reduce splash from out of the bowl. 

Nodules (Peaks and Troughs) resembling pebbles or different shapes at the base of a waterfall. 

Due to the irregular nature of the phenomenon we are handling, our optimization resulted from quantitative and qualitative analysis. 

The P-lsland is a product of two factors in the fluid flow; the first being the velocity of the flow and the second being the geometry of the surface which the fluid impacts. Knowing that fluid velocity is a variable with each user and cannot be controlled, we focus on the geometry of our design.  In our design, pebbles are tangent to the direction of flow and work to gently redirect the path of the fluid and prevent splash and evenly distribute the fluid.

As well as having a circular dome curve to redirect the flow, the pebbles are also angled in varying degrees ranging from 10° to 45 degrees and varying heights (as in peaks and troughs). This ensures that when used properly (le. fluid is directed from any angle in relation to the device) no fluid will impact the urinal at a normal direction to result in splash-back. The dimensions for our design were extrapolated from both current models and human features.

The P-Island ls a variant of three significant design features that incorporates in Its design fine hygiene elements such as impregnated pleasant restroom fragrances, a biological disc housed in a basket attached to the undercarriage of the device for the treatment of and or eradication of malodours which are emitted from the urinal system. 

The Splash – In an adult the point of origin is usually located at +- 70 centimetres to the front or sides of the urinal (our research shows that we can control this variable consistently). 

Splash Back Results

We observed close to zero splash-back. Even when we drastically altered the point of origin and increased the velocity of the stream, there was very little splash-back.

However, a significant deflection of the flow was observed and because ol our understanding of the phenomenon of splash there is micro-splash (micro-droplets) that is unobservable with our current procedure.


Fragrances and deodorants for plastics are used in a variety of applications and are playing a growing role in marketing consumer products for the home, health and hygiene markets.