Sharing information and promoting earthbag building
|Automated Earthbag Filling Machine
by Dr. Owen Geiger
Strawbale houses were first built shortly after the invention of the baling machine. Settlers in western Nebraska who had access to this machine were quick to realize the potential of large, insulated building blocks. And the rest of the story, as they say, is history. This same potential now exists for earthbag building.
Earthbag buildings are strong, safe, durable, affordable, sustainable, energy efficient and not prone to moisture damage. They are ideal for owner-builder projects because the necessary skills are easy to learn and few tools are required. Earthbag buildings provide excellent protection against wind, rain, heat, cold, snow, bullets, fire, flooding, hurricanes and noise.
But earthbag building does have a downside - filling, tamping and moving the bags is labor intensive. The labor can be reduced somewhat by using lightweight volcanic gravel, but it's still a lot of work.
This could change with the invention of the automated bag filling machine. Originally designed for flood control projects, the Ensor Equipment bag filling machine has enormous potential for changing the future of earthbag building, especially large scale projects such as housing developments, warehouses, factories, shops, schools and other civic structures.
It is interesting to note that the communities hardest hit by floods, hurricanes and tornadoes are the same communities who have the most to gain from building with bags. Well-designed earthbag structures can withstand all but the most extreme situations. Not only can lives be saved, but also billions of dollars in reconstruction costs.
Imagine a vulnerable coastal community along the Gulf of Mexico or the eastern seaboard investing in one of these automated bag filling machines. The machine could do double duty: It could help build or reinforce dikes and levees as needed to help protect the community; the rest of the year it could be used to build flood and storm resistant buildings. On a community scale, the payoff would be very fast.
Ernest E. Engle , Vice President of Ensor Equipment describes their machine as a "high-speed, fully automated sandbagging machine that can produce sewn-closed bags unattended. The machine is fully transportable. The machine uses wet or dry sand, earth, gravel, small rocks or any flowable material. Sewn closed bags each contain an equal amount of sand. Therefore they can be stacked higher and tighter than open or tied-end sandbags." What Mr. Engle has just described is exactly what's needed for constructing earthbag buildings quickly and efficiently.
Ensor SBM 1200 standard features:
Interview with company co-founder CEO/President Mark E. Ensor, P.E.
Owen: What size are your custom bags?
Mark: The filled bags conform to the same sizes as typical mil-standard sandbags. The most common is the 14x26 bag (measured empty). The only difference is that they are sewn closed and have a flap that is about 2.5" long that extends from the bottom and top.
Owen: What is the approximate weight of filled bags?
Mark: 40 lbs is the most common for 14x26 bags, but the weight is adjustable. 12x26 bags are around 30 lbs.
Owen: Why use custom bags and not standard sized bags?
Mark: The only thing custom about the bags is that they are attached end to end by a flap of material so they can be fed automatically into our machine. We have qualified 15 manufacturers from all over the world to make the bags such as the United States , Mexico , China , Thailand , Vietnam , India , and Pakistan . So the bags are easy to get.
Owen: Which ones are most economical?
Mark: There has been a push lately for 12x26 bags not only because they are cheaper since they are smaller, but because they perform almost as well as the 14x26 bags with less material. Less material also translates to cheaper. The narrower the bag, the more bags can be put on a container, which translates to more bags per container and therefore lower shipping costs per bags.
Owen: How many 14x26 bags (measured when empty) can be filled per hour?
Owen: Can your machine handle 18x27 bags?
Yes the machine will fill them. I don't know how fast because we haven't done it in a while. But I suspect it will be around the same speed for dry flowing sand (and polypro bags) as the 14x26 bags. Wet sand filling might be slower than normal.
Owen: Are you willing to go to a jobsite and fill bags for someone's house? And, if so, how much would it cost? (Let's assume you are in the vicinity already.)
Mark: The short answer is that if it makes sense on paper we will do it. The biggest issues with remote jobs is housing the crew, transporting the loader, and transporting the material. If all three things are provided, we can provide and fill our poly bags anywhere from $.35 per bag to $.75 per bag all depending on our expenses. The bags are provided at these costs.
Owen: Will your machine work with road base and other flowable soils that have clay content?
Mark: High clay content is fine as long as the material is dry. Once the material gets wet, it starts to coat the machine and belt, and we have to clean it all off periodically. But otherwise, it works fine. We have provisions in the machine to deal with non flowing material, such as wet sand which doesn't coat the machine like wet clay or wet reconstituted cement does.
Owen: How much for the machine? Maybe someone is interested in becoming a contractor.
Mark: The machines range from $130k for a basic skid mounted machine that plugs in to facility power to $240k for a trailer mounted version with a built-in generator, extending conveyors, and storage.
Owen: What size tractor or front end loader is typically used?
Mark: The machine can be filled with the big skid steers available from John Deere, Mustang, and Bobcat, (and others) and medium sized Skip Loaders - such as the John Deere 210 (we use the John Deere 210). I'm not aware of a Cat Skip Loader that is too small to fill the machine (except some of the small Bobcat Loaders). The machine has an 89" dump height.
Owen: Do you have any other comments you would like to add about how this machine can be used for constructing buildings?
The Ensor Equipment homepage (www.ensorequipment.com )has a video that shows the machine in operation.
I've written extensively about building with bags for the Earthbagbuilding.com website and blog, and The Last Straw journal. It grieves me to see the same problems in the news year after year - the tragic destruction of countless homes and businesses by floods, tornadoes and hurricanes. Much of this destruction is preventable with sensible planning and proper building design. Due to a lack of leadership at state and national levels it's time for communities to take greater steps to protect themselves from natural disasters.
Another bag filling machine is described at www.q-fill.com.
Owen Geiger, Ph.D. is a TLS Correspondent, Director of the Geiger Research Institute of Sustainable Building (GRISB), www.grisb.org , and co-developer of Earthbagbuilding.com. GRISB, along with partner organizations and designers, developed two disaster-resistant designs in response to the 2004 Indian Ocean earthquake and tsunami. Dr. Geiger is currently developing emergency shelter designs for UN relief operations (www.earthbagbuilding.com/pdf/UN earthbag shelters.pdf), and assisting United Houma Nation with hurricane and flood-resistant housing efforts in southern Louisiana .
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