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The Science Behind Making Buildings Comfortably Non-Combustible

Although the most fire-resistant building is likely a windowless, concrete bunker, this tends to be not the vibe that most home owners go for. This is why over the years construction of buildings in areas prone to bush- and wildfires – i.e. an uncontrolled fire in an area with combustible vegetation – has adapted to find a happy medium between a building that you’d enjoy living in and a building that will not instantly combust the moment an ember from a nearby wildfire gently touches down upon any part of it.
To achieve this feat, the primary means include keeping said combustible vegetation and similar away from the building, and to make the house as resistant to ember attacks as possible. That this approach is effective has been demonstrated over the course of multiple wildfires in California during the past years, whereby houses constructed more recently with these features had a much higher chance of making it through the event unscathed.
Naturally, the devil is in the details, which is why for example the Australian standard for construction in bushfire-prone areas (AS 3959, last updated in 2018, 2009 version PDF) is rather extensive and heavy on details, including multiple Bushfire Attack Level (BAL) ratings that define risk areas and legally required mitigation measures. So what does it take exactly to survive a firestorm bearing down on your abode?

Wild Bushfires
Fire is something that we are all familiar with. At its core it’s a rapid oxidation reaction, requiring oxygen, fuel, and some kind of ignition, which can range from an existing flame to a lightning strike or similar source of intense heat. Wild- and bushfires are called this way because the organic material from vegetation provides the fuel. The moisture content within the plants and branches act to set the pace of any ignition, while the spread of the fire is strongly influenced by wind, which both adds more oxygen and helps to distribute embers to susceptible areas downwind.
This thus creates two hazards: the flame front and the embers carried on the warm air currents, with the latter capable of travelling well over a kilometer in ideal conditions. The level of threat will differ of course depending on the region, which is what the Australian BAL rating is about. As each higher BAL comes with increasing risk mitigation costs it’s important to get this detail right. The main factors to take into account are flame contact, radiant heat and ember attack, the risk from each depending on the local environment.
In AS 3959-2009 this risk determination and mitigation takes the form of the following steps:

Look up the predetermined Fire Danger Index (FDI) for the region.
Determine the local vegetation types.
Determine the distance to classified vegetation types.
Determine the effective slope(s).
Cross-reference tables with these parameters to get the BAL.
Implement the construction requirements as set out by the standard.

The FDI (see table 2.1) is a fairly course measurement that is mostly set by the general climate of the region in question, which affects parameters like air temperature, humidity, wind speeds and long- and short-term drought likelihoods. Many parts of Australia have an FDI of 100 – the highest rating – while for example Queensland is 40. When putting these FDI ratings next to the list of major bushfires in Australia, it’s easy to see why, as the regions with an FDI of 100 are overwhelmingly represented on it.
Vegetation Angle
Not all vegetation types are equally dangerous, with both the distance and slope to them changing the calculation. The vegetation type classification ranges from forest to unmanaged grassland, most of which are further subdivided into a number of sub-categories, such as woodland being sub-divided into open, low or a combination thereof. This kind of classification is of course highly dependent on the country’s native vegetation.
Determination of distance of site from classified vegetation (Source: AS 3959-2009, Figure 2.1)
Following on this are the edge to the thus classified vegetation, such as the beginning of the forest or shrubland, and the effective slope between it and the house or construction site. This determines how close the flame front can get, the effective radiant heat and the likelihood of embers reaching the site. If the building is downslope, for example, embers will have a much easier time reaching it than if they have to find their way upslope.
For certain areas with low-threat vegetation as well as non-vegetated areas the resulting BAL will be ‘low’, as this renders the threat from all three risk factors essentially nil.
Threat Mitigation
The BAL can thus be determined for one’s (future) abode either painstakingly using the Australian Standard document, or by using e.g. the CSIRO’s online tools for new and existing structures. Either way, next comes a whole list of mitigations, which at least in Australia are generally required to fulfill local regulations. These mitigations include any adjacent structures (garage, carport, etc.).
One exception here is with BAL-LOW, which has no specific requirements or mitigations. The first BAL where measures are required is BAL-12.5, which has to cope with ember attack, burning debris and radiant heat up to 12.5 kW/m2. The next two levels bump this up to 19 and 29 kW/m2, before we get the final two levels that include the flames reaching the building either intermittently (BAL-40) or engulf fully (BAL-FZ, i.e. Flame Zone).
Regardless of the BAL, most of the mitigations are rather similar:

any external surfaces exposed to potential embers, radiant heat and/or flames shall be either non-combustible, or bushfire-resistant.
gaps and vents larger than 3 mm must be covered with a (bushfire) mesh that has a maximum aperture of 2 mm.
installation of bushfire shutters to protect windows and doors.
non-combustible roof tiles, sheets, etc.

One aspect that differs here is the setback distance, which for BAL-FZ is at least 10 meters between the house and the classified vegetation, which is less stringent with the other BALs.
Common Sense
Many of these measures are common sense, albeit it that the devil is in the details. What the right type of bushfire mesh or sealant is to keep embers out, for example, or the best kind of siding. Fortunately this kind of information is readily available, which makes a solid assessment of one’s abode the most crucial step. Perhaps the most crucial one after assessing gaps is the removal of flammable material near the house, including bushes and other vegetation, and the consideration of what’d happen if any part of the house exterior got exposed to embers, radiant heat and/or flames.
So-called wall and roof penetrations like skylights, AC units and ventilation can inadvertently become welcoming entrances. This plays a major role in the US, for example, where attic venting is very common. Without mesh keeping embers out, such vents will do what they’re designed to do, which is circulating (ember-filled) outside air. Generally the local fire department in bush- and wildfire prone areas will have resources to help hardening one’s home, such as CalFire’s dedicated resource site.
Although keeping up with these defenses is not super-easy, it bears keeping in mind that in the case of a major fire it can only take a single ember to compromise every other measure one might have taken. Since big fires do not generally announce themselves weeks in advance, it’s best to not put off repairs, and have a checklist in case of a wildfire so that the place is buttoned up and prepared when the evacuation notice arrives.
Though following all mitigations to the letter is no guarantee, it will at least give your abode a fighting chance, and with it hopefully prevent the kind of loss that not even the most generous fire insurance can undo.
Featured image: “Deerfire” by John McColgan […]

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Teaching AI safety: Lessons from Romanian educators

This blog post has been written by our Experience AI partners in Romania, Asociatia Techsoup, who piloted our new AI safety resources with Romanian teachers at the end of 2024.

Last year, we had the opportunity to pedagogically test the new three resources on AI safety and see first-hand the transformative effect they have on teachers and students. Here’s what we found.

Romania struggles with the digital skills gap

To say the internet is ubiquitous in Romania is an understatement: Romania has one of the fastest internets in the world (11th place), an impressive mobile internet penetration (86% of the population), and Romania is leading Central and Eastern Europe in terms of percentage of population that is online (89% of the entire population). Unsurprisingly, most of Romania’s internet users are also social media users. 

When you combine that with recent national initiatives, such as

The introduction of Information Technology and Informatics in the middle-school curriculum in 2017 as a compulsory subject

A Digital Agenda as a national strategy since 2015 

Allocation of over 20% of its most recent National Recovery and Resilience Fund for digital transition

one might expect a similar lead in digital skills, both basic and advanced.

But only 28% of the population, well below the 56% EU average, and just 47% of young people between 16 and 24 have basic digital skills — the lowest percentage in the European Union. 

Findings from the latest International Computer and Information Literacy Study (ICILS, 2023)  underscore the urgent need to improve young people’s digital skills. Just 4% of students in Romania were scored at level 3 of 4, meaning they can demonstrate the capacity to work independently when using computers as information gathering and management tools, and are able, for example, to recognise that the credibility of web‐based information can be influenced by the identity, expertise, and motives of the people who create, publish, and share it.

Furthermore, 33% of students were assessed as level 1, while a further 40% of students did not even reach the minimum level set out in the ICILS, which means that they are unable to demonstrate even basic operational skills with computers or an understanding of computers as tools for completing simple tasks. For example, they can’t use computers to perform routine research and communication tasks under explicit instruction, and can’t manage simple content creation, such as entering text or images into pre‐existing templates.

Why we wanted to pilot the Experience AI safety resources

Add AI — and particularly generative AI — to this mix, and it spells huge trouble for educational systems unprepared for the fast rate of AI adoption by their students. Teachers need to be given the right pedagogical tools and support to address these new disruptions and the AI-related challenges that are adding to the existing post-pandemic ones.

This is why we at Asociația Techsoup have been enthusiastically supporting Romanian teachers to deliver the Experience AI curriculum created by the Raspberry Pi Foundation and Google DeepMind. We have found it to be the best pedagogical support that prepares students to fully understand AI and to learn how to use machine learning to solve real-world problems.

Testing the resources

Last year, we had the opportunity to pedagogically test the new three resources on AI Safety and see first-hand the transformative effect they have on teachers and students.

We worked closely with 8 computer science teachers in 8 Romanian schools from rural and small urban areas, reaching approximately 340 students between the ages of 13 and 18.

Before the teachers used the resources in the classroom, we worked with them in online community meetings and one-to-one phone conversations to help them review the available lesson plans, videos, and activity guides, to familiarise themselves with the structure, and to plan how to adapt the sessions to their classroom context. 

In December 2024, the teachers delivered the resources to their students. They guided students through key topics in AI safety, including understanding how to protect their data, critically evaluating data to spot fake news, and how to use AI tools responsibly. Each session incorporated a dynamic mix of teaching methods, including short videos and presentations delivering core messages, unplugged activities to reinforce understanding, and structured discussions to encourage critical thinking and reflection. 

Gathering feedback from users

We then interviewed all the teachers to understand their challenges in delivering such a new curriculum and we also observed two of the lessons. We took time to discuss with students and gather in-depth feedback on their learning experiences, perspectives on AI safety, and their overall engagement with the activities, in focus groups and surveys.

Feedback gathered in this pilot was then incorporated into the resources and recommendations given to teachers as part of the AI safety materials.

Teachers’ perspectives on the resources

It became obvious quite fast for both us and our teachers that the AI safety resources cover a growing and unaddressed need: to prepare our students for the ubiquitous presence of AI tools, which are on the road to becoming as ubiquitous as the internet itself.

Teachers evaluated the resources as very effective, giving them the opportunity to have authentic and meaningful conversations with their students about the world we live in. The format of the lessons was engaging — one of the teachers was so enthusiastic that she actually managed to keep students away from their phones for the whole lesson. 

They also appreciated the pedagogical quality of the resources, especially the fact that everything is ready to use in class and that they could access them for free. In interviews, they also appreciated that they themselves also learnt a lot from the lessons:

“For me it was a wake-up call. I was living in my bubble, in which I don’t really use these tools that much. But the world we live in is no longer the world I knew. … So such a lesson also helps us to learn and to discover the children in another context, – Carmen Melinte, a computer science teacher at the Colegiul Național Grigore Moisil in the small city of Onești, in north-east Romania, one of the EU regions with the greatest poverty risk.

What our students think about the resources

Students enjoyed discussing real-world scenarios and admitted that they don’t really have adults around whom they can talk to about the AI tools they use. They appreciated the interactive activities where they worked in pairs or groups and the games where they pretended to be creators of AI apps, thinking about safety features they could implement:

“I had never questioned AI, as long as it did my homework,” said one student in our focus groups, where the majority of students admitted that they are already using large language models (LLMs) for most of their homework.

“I really liked that I found out what is behind that ‘Accept all’ and now I think twice before giving my data,” – Student at the end of the ‘Your data and AI’ activities.

“Activities put me in a situation where I had to think from the other person’s shoes and think twice before sharing my personal data,” commented another student.

Good starting point

This is a good first step: there is an acute need for conversations between young people and adults around AI tools, how to think about them critically, and how to use them safely. School is the right place to start these conversations and activities, as teachers are still trusted by most Romanian students to help them understand the world.

But to be able to do that, we need to be serious about equipping teachers with pedagogically sound resources that they can use in class, as well as training them, supporting them, and making sure that most of their time is dedicated to teaching, and not administration. It might seem a slow process, but it is the best way to help our students become responsible, ethical and accountable digital citizens.

We are deeply grateful to the brave, passionate teachers in our community who gave the AI safety resources a try and of course to our partners at the Raspberry Pi Foundation for giving us the opportunity to lead this pilot.

If you are a teacher anywhere in the world, give them a try today to celebrate Safer Internet Day: rpf.io/aisafetyromania […]

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Precision Reference Puts Interesting Part to Work

Interesting parts make for interesting projects, and this nifty precision voltage reference has some pretty cool parts, not to mention an interesting test jig.
The heart of [Gaurav Singh]’s voltage reference is an ADR1399, precision shunt reference from Analog Devices. The datasheet makes for pretty good reading and reveals that there’s a lot going on inside the TO-49 case, which looks unusually large thanks to a thick plastic coat. The insulation is needed for thermal stability for the heated Zener diode reference. The device also has a couple of op-amps built in, one that provides closed-loop voltage control and another that keeps the internal temperature at a toasty 95°C. The result is a reference that’s stable over a wide range of operating conditions.
[Gaurav]’s implementation maximizes this special part’s capabilities while making it convenient to use. The PCB has a precision linear regulator that accepts an input voltage from 16 V to 20 V, plus a boost converter that lets you power it from USB-C. The board itself is carefully designed to minimize thermal and mechanical stress, with the ADR1399 separated from the bulk of the board with wide slots. The first video below covers the design and construction of an earlier rev of the board.
One problem that [Gaurav] ran into with these boards was the need to age the reference with an extended period of operation. To aid in that, he built a modular test jig that completed PCBs can be snapped into for a few weeks of breaking in. The jigs attach to a PCB with pogo pins, which mate to test points and provide feedback on the aging process. See the second video for more details on that.

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