Youth Month: Alumni’s DIY foam fire extinguisher most popular hack

08 June 2023 | Story Helen Swingler. Photos Supplied. Read time 8 min.
Final-year chemical engineering students Desania Govender and Yandisa Sojola during fire testing in 2015. Their DIY foam fire extinguisher, developed for their final-year project, is now the top hack on dooiy.
Final-year chemical engineering students Desania Govender and Yandisa Sojola during fire testing in 2015. Their DIY foam fire extinguisher, developed for their final-year project, is now the top hack on dooiy.

A do-it-yourself (DIY) foam fire extinguisher developed in 2015 by two University of Cape Town (UCT) students to combat fires in informal settlements has been given a new lease of life via international open-sharing platform The device was designed for their final-year chemical engineering project.

The former high school and university mates and graduates Desania Govender and Yandisa Sojola are now working in Ireland and Secunda respectively. Eight years ago, the pair took an existing idea for a DIY fire extinguisher and developed it for communities living in shacks, where fire is a constant hazard. This threat has grown with loadshedding as more families turn to candles and paraffin to light and fuel their homes.

The low-cost foam extinguisher uses common household products and waste. The basics are a two-litre cooldrink bottle, water, vinegar, dishwashing liquid and bicarbonate of soda.

Final-year chemical engineering students Desania Govender (left) and Yandisa Sojola presented their DIY fire extinguisher project in 2015.

Most popular hack

“The idea for our fire extinguisher was initiated by a school project with a similar design,” said Govender, now in Ireland where she works as a business modelling consultant. She and Sojola expanded and developed the design, activation mechanism and combination of ingredients.


“The fire extinguisher is now the most popular hack on the dooiy platform.”

Their device works for class A fires (solid combustibles such as cardboard, wood, plastics and cloth) and class B fires (flammable liquids such as gasoline or petroleum). Smothering works best to douse these fires. The foam produced by a chemical reaction set off within the bottle does this very effectively. (The main chemical reaction comes from the interaction between the vinegar and the bicarbonate of soda, generating pressure. The foam comes from the dishwashing liquid.)

“We are proud that the fire extinguisher is now the most popular hack on the dooiy platform,” said Govender. She and Sojola, a process engineer at SASOL in Secunda, are delighted at the renewed impetus. Sojola grew up in Gugulethu and is well familiar with the threat of fire in densely built urban townships.

Although chemical engineering students don’t get to choose their final-year assignment, Govender and Sojola said they were fortunate to work on such a high-impact project.

“Having grown up in Cape Town and especially in winter, we would often hear about fires destroying hundreds of homes due to how densely built people’s homes are in informal settlements,” said Sojola.

“What drew us to the project is that it would impact the community,” said Govender.

With limited time, they couldn’t visit informal settlements, but were able to tap into a wealth of research to answer important questions. What were the distances between shacks? What devices could be used? Were these accessible to these communities?

Once they had a prototype, they conducted foam experiments on upper campus and “hot testing” at the South African Fire and Medical Academy.

Just ‘dooiy’ it

That their device has been given a second “encore” is thanks to technology and its reach. As part of their project, Govender and Sojola created an instructional pamphlet for their DIY extinguisher. This is what Marlene Lerch, the co-founder of dooiy and German non-profit organisation Hack Your Shack, found when she was searching the web for DIY hacks.


“All those good solutions out there have no reach.”

Other hacks on their platform include a bucket washing machine made with two buckets and a toilet plunger, a kitchen module with an integrated sink, a vertical garden made from plastic bottles, and a smart cooker. These hacks make life easier and safer for people living in informal settlements and other under-served communities across the world.

“It is really hard to find applicable solutions for informal settlements on the internet, and all those good solutions out there have no reach,” said Lerch. This was the impetus for the dooiy platform, designed and built by her software engineer husband, Christian.

The easy-to-access platform consumes very little data and battery power. It fulfils their mission to make “actionable open-source knowledge accessible to everyone anywhere, no matter the price of your data, income or language”.

South African pilot

The dooiy website is being piloted in South Africa and was launched in February this year. The plan is to roll it out globally, supporting the South–South exchange of knowledge, resources and technology between developing countries in the Global South.

The team has since adapted Govender and Sojola’s device, making it cheaper and easier to build for mass production.

The spread of the fire extinguisher is particularly close to Lerch’s heart because she witnessed the March 2022 fire in Nomzamo near Strand where 250 homes were lost in one night.

“It was horrible; people lost all their belongings.”

She took the hack idea to community leaders. Afterwards the community came together to learn how to make DIY foam fire extinguishers.

“People were sceptical at first,” said Lerch. “But after dooiy showed the fire extinguisher in action, everyone was very excited.”

They made 120 fire extinguishers in one afternoon.


“Everyone [in these communities] has a story to tell about fire.”

“We also know [about] one woman who [later] had a gas incident in her home but was able to put out the flames with the fire extinguisher that she built with us,” said Lerch. “That might have been the next major fire in this community.

“Whenever people in these communities visit the dooiy site, they go straight to the fire extinguisher and say, ‘This is what we need. This is the real danger.’ Everyone [in these communities] has a story to tell about fire.”

She added, “We are currently building a lot of partnerships to spread the word about dooiy to grow the impact of the platform. Our goal is to unleash the power of making and support a new way of self-help to improve living conditions and create new income possibilities. Because of its great potential, the dissemination of the fire extinguisher is particularly important to us, and we are working towards the goal that every household has a fire extinguisher at home.”

Workshops and collaboration

In the past year, the Hack Your Shack team have run fire extinguisher workshops in different communities across the Western Cape, reaching over 800 people.

They have also teamed up with the City of Cape Town to run DIY fire extinguisher workshops. The City’s Smart Living Education Centre has already begun to incorporate this information in their education programme, which has reached more than 200 young people so far.

Yandisa Sojola grew up in Gugulethu and understands the dangers of shack fires in informal communities..

Collaboration is the way to go, said Lerch. dooiy is an open-source project that benefits from the contributions of makers, NGOs or universities who share their expertise on the platform.

“There are many more impactful and applicable solutions out there that would be great to make accessible on dooiy – or that could be created together.”

One of the new sets of instructions Lerch is working on together with a German foundation is for DIY biochar, a carbon-rich substance used to rejuvenate soil and promote plant health.

She hopes to team up with other departments and young innovators at UCT to develop similarly useful and inexpensive ideas to make life easier for those living in informal settlements.

There are more possibilities on the cards for the DIY foam fire extinguisher. Lerch is consulting with Professor Harro von Blottnitz, the head of UCT’s Environmental & Process Systems Engineering Research Group in the Department of Chemical Engineering, to take the idea further in its design and development – a possible final-year topic for students in 2023.

 “We think that further improvements to the design would be possible,” said Lerch.

Govender and Sojola are excited by the possibilities too.

“It’s been so nice to watch the progress,” said Govender.

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Youth Month 2023

Youth Month 2023

This Youth Month, UCT News will profile young University of Cape Town (UCT) community members who are hard at work across South Africa in an effort to make a difference in society. The month of June holds significance in the country as it is a commemoration of the historic tragedy of 16 June 1976 when hundreds of youth were killed while protesting against unjust education policies.




“We can and must change things for ourselves and improve the state of this country for those who will come after us.
We can’t do that while being idle.”
Sukainah McCabe, a fourth-year social work student


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