Competencies - June 2023

Perforated plate seeks paste

Towards an international standard for shower toilets

How effective is a shower spray actually? Finding a standard that would meet international acceptance proved to be a Herculean task for the responsible standardisation organisation. But then, two Geberit employees had some decisive flashes of inspiration.

This assignment was anything but ordinary. Even for Markus Ott. The project manager and technician of Geberit's sanitary laboratory was faced with the task of developing a measuring method for the cleaning effect of the water jet of shower toilets. The challenge: It has to be reproducible and comparable. Not to mention acceptable to the majority. After all, the process would then be adopted by the standards committee of the International Electrotechnical Commission (IEC). In addition to Geberit, representatives of Japanese and Spanish sanitary companies also sit on this committee.

The idea with the perforated plate
Markus Ott got to work – and found the solution with the help of a perforated plate: The plates, which are between 2 and 10 millimetres thick, have a mesh of small holes that are filled with a paste and then washed off using the spray arm. The measurement criterion – at a precisely defined water temperature, water pressure and shower duration – is the number of flushed-out holes. The perforated plate was unanimously approved by the standards committee, but opinions were divided on the paste.

“I knew that only a synthetically produced paste would end the deadlock in the committee.”
Markus Gantenbein, Head of the Materials Laboratory

Miso versus mustard
The Asian protagonists wanted to use a soy-based miso paste, while the Western faction insisted on testing using mustard. This was compounded by the fact that neither of the two solutions met the criterion of a standardised paste. Markus Gantenbein, Head of the Materials Laboratory in the Technology and Innovation department at Geberit, was tasked with finding an alternative. “I knew that only a synthetically produced paste would end the deadlock in the committee,” he says in retrospect.

Just like grandma used to make
In the following weeks, the lights in the Materials Laboratory burned longer than usual in the evenings – Gantenbein developed pastes. After several prototypes and tests, he found what he was looking for. A recipe of citric acid, calcium chloride, cellulose, water, a dash of food colouring and pectin – a gelling agent that grandma used to make jam, seemed to him worthy of compromise. And he was proven right: The paste withstood the critical scrutiny of all committee members. Miso and mustard were history.

Bone-crushing standard work
Measuring the cleaning effect of the shower spray is just one of 13 test processes currently prescribed for shower toilets, which the IEC summarises under the somewhat unwieldy standard designation “Electrically operated spray seats for the household and similar purposes”. A consensus or majority decision must be reached for each individual test process. Markus Gantenbein knows that working with standards is tough: “Nobody on the committee wants a standard that is detrimental to their own products. This is why every detail of the test processes is thoroughly negotiated.”