SINTEF TEST OF A UNIQUELY NORWEGIAN LINT PROBLEM

– We discovered that this only happens in Norway, with both new and old tumble dryers. We want to find the cause, as this creates a poor customer experience when the drying process has to be interrupted, and it causes additional wear on the clothes, says Jan Røsholm, chief executive of the Elektronikkbransjen Foundation.

Before the summer, the trade association commissioned Sintef to investigate why many retailers, repair workshops and white goods suppliers have received an increasing number of reports over the past six months of unusually large amounts of lint forming in tumble dryers.

Røsholm says the matter was raised by Applia Norway, which is part of the Elektronikkbransjen Foundation, on behalf of white goods suppliers, following many customer reports that the lint filter has to be emptied up to two or three times per drying cycle.

Independent test

– When we wanted to find the cause, we discussed whether to use internal resources. Both suppliers and repair workshops are highly competent, but we wanted an independent institution to conduct the tests. Sintef is definitely best in class here, Røsholm tells the Elektronikkbransjen trade journal.

We join him at Sintef, located between Blindern and Gaustad in Oslo, where the tests are being carried out in the laboratory of the Department of Materials and Nanotechnology.

Here we meet senior researcher Stephan Kubowicz, who received the enquiry from Røsholm.

– I thought this was exciting. I have not encountered the issue myself, but we were positive about the enquiry, says Kubowicz.

– Is this a typical assignment for you?

– No, not in our group. We have some projects related to textiles, but not exactly of this kind, says Kubowicz.

Three laundry towers

Research engineer Birgitte Vågenes leads the testing itself.

– My role is to start the washing and drying cycles, and document what happens. We weigh the laundry, measure how much lint comes out, and record everything continuously, says Vågenes.

The industry has supplied three laundry towers with a washing machine and tumble dryer, from Electrolux, Samsung and Siemens, with equivalent programmes used for the test.

– We have chosen 40-degree cotton and the same conditions every time. We standardise the amount of laundry and detergent in order to be able to say something about the effects. We use three kilograms per washing and drying cycle, and follow the recommendations for using the machines, says Vågenes.

Programmes with automatic functions and the use of artificial intelligence have been excluded.

– We want to compare the washes on an equal basis. If the programmes adjust themselves, we lose reference points such as time and detergent quantity. Then we cannot compare them, says Kubowicz.

Textiles and detergents

Sintef is testing towels from three suppliers.

– We are using bath towels from Ikea, Kid and Princess in the same price range, with Ikea being slightly cheaper. We wash with both liquid and powder detergent, with and without fabric softener, and these products were bought from random shops. We started with fabric softener and liquid detergent, as we assume this may have the greatest effect on lint formation, says Kubowicz.

– Is the aim to simulate normal use?

– Yes, we choose the programme most people use, 40-degree cotton, followed by drying, says Kubowicz.

– How many wash cycles are you planning?

– We have envisaged up to 20 washes, but will assess this as we go along based on how much lint is produced and whether the problem occurs, says Vågenes.

New and unique to Norway

Røsholm says the phenomenon is new.

– This emerged a year and a half ago. Previously, it was not a problem. This raises the question: Why did it become a problem in autumn 2024? says Røsholm.

– What do you think could be the cause?

– We do not want to pre-empt anything. The same machines are sold in many countries, but since this is only a problem in Norway, we do not think it is the hardware. The water quality is the same in the north and south, so we do not think it is the water either. That leaves the detergents or the textiles. It is Sintef’s job to find out, says Røsholm.

Standardisation and use

Vågenes says that washing habits differ.

– There is great variation in people’s homes. Some use liquid detergent, others powder, and the amount of laundry varies. Here, we standardise: the same amount of laundry, the same amount of detergent and identical programmes, says Vågenes.

The test is being conducted at the Department of Materials and Nanotechnology.

– Our group is called polymer and composite materials. There are 10–11 of us in the group and 80–90 in the department, says Kubowicz.

– What other kinds of projects do you work on?

– For example, we are looking at using recycled materials in drainage pipes, we are testing degradable polymers for fishing nets, and examining material properties. There is a wide range of work. This laundry matter is something completely different, says Kubowicz.

Starting with the hypothesis

– How often does the client’s hypothesis prove correct?

– It is difficult to say. Sometimes it fits, because they know the products well. We start with the hypothesis, test it, and if it does not hold up, we investigate further, says Kubowicz.

Kubowicz and Vågenes admit that their Sintef colleagues joke about the mundane and familiar nature of the study.

– People in the building keep asking whether we are running a laundry service, and whether we can do their washing for them, says Kubowicz.

– Do you empty the lint filter yourselves at home?

– Yes, every time. I have always done that, says Kubowicz.

– We do that at home too, but I do not weigh and log it afterwards, says Røsholm.