“I want to build with my ecobricks, but I am worried about what would happen to them in case of fire. What do you guys advocate for ecobrick fire safety?”
– Amanda, UK
Thank you for your question. The issue of ecobrick fire safety is an important one. I observe that concerns for ecobrick flammability come largely from misconceptions of how ecobricks are applied. Many folks see bricks and ecobricks as the same sort of thing, when in fact their applications are very different. Personally, I use ecobricks in my home for my garden bench and my hexagon modular furniture. I am honestly more concerned about my traditional furniture catching fire, than I am my ecobricks!
So let’s take a look at the issues…
As we all know, plastic in the wrong place is toxic. Especially if it is in a fire! When plastic burns it releases all sorts of nasty fumes. And so too when it degrades in other ways. That’s the reason after all why we are ecobricking: to safely and securely trap plastic in a bottle. Likewise, this is the same pursuit when building with ecobricks. We want to ensure our constructions safely and securely contain the ecobricks.
Of course, it is helpful to remember that given the right conditions, everything burns.
When we build with wood we do so attentive to the various properties of wood and the conditions in which it will start to burn. When we build with ecobricks we do the same: we build in ways that minimize or even completely remove the risk of fire.
The first step in fire safety is ensuring that the ecobricks that you use are packed to the proper density.
The GEA best-practice guideline is 0.33g/ml for ecobrick density. This means a minimum of 200g for a 600ml bottle, and 500g for a 1.5ml bottle. By packing the ecobrick tight to these specifications, the amount of oxygen in the bottle is minimized. This makes it much more difficult for an ecobrick to catch on fire, than say a bottle loosely packed with plastic. In fact, a properly packed ecobrick is almost impossible to light on fire! In this way, a module made of densely packed ecobricks is far less flammable than an upholstered foam or Dacron filled mattress or couch!
The second step is ensuring that you are building properly with your ecobricks. The GEA’s recommended building method is with earthen mortar. In this way, ecobricks are laid horizontally in cob (a mix of clay, sand and organic binder). For foundation, the ecobricks are half laid in cement and half in cob. There is typically a 3-5cm space of cob mortar between the bottles. When walls are built this way, they are virtually impossible to set on fire. Cob walls have been known to stay intact long after wood beams and wood floors have turned to ash. For absolute fire safety, you can opt to cover the exposed caps and bottoms with an earthen or cement render.
Our colleagues in South Africa have done some experiments with ecobrick earthen walls and fire. You can see the results of their tests here…
3 hr Fire wall test - Time lapse
A Travellingtoes production fimed by Tarryn Jolly - This is our 3hrs burn on timelapse. Take a look & see for yourself... I'll dig away the bottom of the wall where the fire was concentrated & we'll inspect the bricks together. The wall at the base baked hard and clay like in the fire, the back of the wall (out of vew of the camera- was also kept burning) but was not hosed down till all the cob plopped off so the ecobrick "reveal" will be easier; less mud to clear. No it wasn't a scientifically monitored burn at a consistent 300 degrees- Waste-ED our "Cob and Ecobrick Family" are going to be doing that with Stellenbosch University. We are utterly satisfied with the outcome of the test- "how long have people got to vacate a burning building before it collapses...." Enough time here. The Folly Chapel is going to be a 5mx 12m building. Can't wait to get started!Posted by The Folly Chapel. Yellowwood Forest. Morgan Bay on Wednesday, December 11, 2019
Finally, please note that contrary to popular assumption, the vast majority of ecobrick applications are for non-structural applications– like gardens bedding, playgrounds, and outdoor benches. These applications of course are not only less prone to flamability, but the risks of their catching fire are far less than that of a structure.
The recommended GEA ecobrick applications are small, outdoor, and non-structural. The vast majority of ecobrickers put their ecobricks to use as module or as gardens. These applications, especially the latter, have minimal risk of catching fire. For outdoor gardens and green spaces, the dangers of their catching fire is likewise minimal.
Thank you again for your question.
Thinking about the potential end of our ecobrick in fire, is an essential reminder of why we are ecobricking in the first place: Plastic can be toxic and dangerous! We thus take responsibility for our plastic and secure it inside an ecobrick. When it comes to building with ecobricks, we are doing the same thing. We want to build in such a way that the ecobricks are safe and secured indefinitely from all forms of degradation — especially fire — so that years, or decades, or centuries from now, the ecobricks can be taken out, and put to good use again and again.
What not to do
When putting your ecobricks to use there are some simple guidelines to keep them fire safe.
- Avoid wrapping them in flamable materials
- Avoid taping your ecobricks together
- Avoid using low density ecobricks
- Avoid using empty bottles along side ecobricks
- Follow the GEA guidelines on recommended ecobrick applications
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