Settlement from the 3D printer: “Genesis Collection” from BIG and ICON

Building design
Render of the Genesis Collection in Wolf Ranch, Texas. Image source: Lennar, ICON and BIG

Render of the Genesis Collection in Wolf Ranch, Texas. Image source: Lennar, ICON and BIG

In Georgetown, Texas, a project called “The Genesis Collection at Wolf Ranch” has begun. BIG, ICON and Lennar are working together to create the world’s largest 3D-printed housing development to date.

In Georgetown, Texas, a project called “The Genesis Collection at Wolf Ranch” has begun. BIG, ICON and Lennar are working together to create the world’s largest 3D-printed housing development to date. The first house is now complete.

3D-printed houses are no longer a novelty. The first 3D-printed house in Germany will open in 2021, and there are already entire villages in Mexico, Russia and China that come from the printer. When scaled up correctly, the 3D printing process promises to deliver energy-efficient and climate-resilient homes. The printing process is much faster than conventional construction and results in novel designs and minimal construction waste. ICON is one of the leading companies in the field of 3D printing. Together with BIG and Lennar, ICON is pioneering the printing of neighborhoods on a larger scale with the Genesis Collection project in Texas.

At first glance, Wolf Ranch appears to be a typical suburban development with 2,500 houses. However, the expansion called “Genesis Collection” with 100 houses built with 3D printers represents an important innovation in residential construction. Once completed, “Genesis Collection” will be the largest 3D-printed housing estate in the world. It is a collaboration between Lennar Corporation, the second largest house builder in the US, and 3D printing startup ICON. The houses were designed by Danish architecture firm BIG.

Jason Ballard, co-founder and CEO of ICON, hopes that this will be a defining moment in the history of construction. Aside from the environmental benefits of 3D printing, the project will also be resilient to increasingly powerful hurricanes, wildfires and heatwaves. Furthermore, Ballard hopes that 3D printing and robotic construction can end the global housing crisis.

For Lennar Corp., pressures such as labor shortages, rising material costs and pressure to reduce the carbon footprint of homes mean the industry must innovate. “We’ve been building houses the same way for centuries,” says Stuart Miller, Executive Chairman of Lennar. He explains that the company is looking for techniques and solutions to build more effectively, efficiently and affordably.

It was this belief that led Lennar to invest in Austin-based 3D printing startup ICON. Since its founding in 2017, ICON has already raised USD 451 million. This includes a contract from NASA to explore 3D printing and construction on the surface of the moon. Back on Earth, Wolf Ranch is an important project that will provide data on the potential of 3D printing to save time and money on construction sites.

ICON works primarily with Vulcan printers, a technology the startup debuted in 2018. These machines use a proprietary concrete mix called Lavacrete, which layers the concrete to form exterior and interior walls. At Wolf Ranch, the latest version of the Vulcan printer is in use. It is almost as big as a house: 14 meters wide and 4.7 meters high. The printing robot consists of a crossbar that moves up and down on the two high towers, which stand on a foundation. A nozzle is attached to the crossbar, which swings from side to side to create the layers.

Currently, seven robots are busy building the “Genesis Collection” and piling up Lavacrete in Georgetown, Texas. The Wolf Ranch bedroom community is a rapidly growing settlement 30 miles north of the center of Austin. In the construction office, large screens show the progress of the printing robots. Each layer of material dries in about 15 minutes and will eventually fade to a light gray color. It takes about three weeks to complete the walls of a 3D-printed ICON house – about 30 percent less time than it takes to build a conventional house.

The structure is reinforced with rebar, which can then be filled with insulating material. The Vulcan printer also leaves space for windows and doors. Workers are on site to cut out recesses for sockets and light switches. Each printer is operated by four workers, resulting in a quiet construction site where the hum of the printers dominates. The site is clean as there is no construction waste. The printers are controlled via a tablet that contains the software for the various houses in the “Genesis Collection”.

Aside from the productive and environmental benefits, “Genesis Collection” will also show that 3D printing can free construction from the constraints of right angles. Printers like the Vulcan can print curved, folded or half-shell shaped walls. Even the kitchen islands at Wolf Ranch can come out of the printer.

The Genesis Collection consists of differently shaped and designed buildings. Customers can choose one of eight different floor plans. “Rune”, for example, is a three-bedroom house with 186 square meters. “Cato” is a curved three-bedroom model with 165 square meters. While ICON focuses on the automated construction of walls, which are often the most expensive and slowest part of a building, Lennar offers pitched metal roofs. The construction company has a team that will also carry out the foundations and interior fit-out of “Genesis Collection”.

The architecture firm BIG, an investor in ICON, designed the “Genesis Collection”. The specialists at the Danish firm were particularly interested in the potential of 3D printing to free the construction from the geometric constraints of right angles. Lavacrete is flexible and can be bent into undulating shapes, which suits BIG’s curvy design language.

Pricing for the new homes is not yet official, but will likely be in the $400,000 range for the Genesis homes, which is competitive with other new homes at Wolf Ranch. The project is scheduled for completion in 2023.

3D printing on the moon: ICON, a company for construction and 3D printing, has been awarded a contract by NASA – together with the star office BIG – to develop construction systems on the satellite to make life there possible in the future.

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Fall Protection on Playgrounds: Materials, Details, and Best Practices

Building design
A closer look at surfacing and open-space materials related to fall protection on playgrounds
A weathered, painted surface featuring fish motifs—a detail from an urban setting. Photo: ghisini/Unsplash

Fall protection on playgrounds is one of the few areas of outdoor space design where a planning decision directly determines whether or not serious injuries occur. The material beneath and around climbing equipment, the depth of a loose-fill surface, the extent of the impact-absorbing zone, and the quality of maintenance are not minor details on the periphery of a design, but rather core technical tasks that are regulated by standards, relevant to liability, and whose effects are physically measurable. Anyone who plans, builds, or operates playgrounds must fully understand fall protection.

  • What fall protection on playgrounds entails and which standards govern it.
  • How the critical fall height is defined and what it means for planning
  • What types of impact protection materials exist, how they work, and how they differ.
  • How to correctly dimension and demarcate fall protection zones
  • What installation depths and maintenance requirements apply to bulk materials?
  • How bonded and unbonded impact protection surfaces compare in practice
  • What common planning and implementation errors occur and how they can be avoided.
  • How fall protection can be integrated into the broader context of playground planning, biodiversity, and the urban climate.

Basics: What fall protection on playgrounds means and which standards apply

Fall protection on playgrounds refers to all measures designed to reduce the impact energy of a falling child to such an extent that life-threatening or serious injuries—particularly head injuries—are prevented. Minor injuries such as scrapes or bruises are not considered an exclusion criterion, but rather an accepted residual risk of play. This distinction is enshrined in regulations and fundamental to planning: playgrounds should not be risk-free, but safe in the sense of a calculated, developmentally appropriate level of risk.

The relevant series of standards for playground equipment and impact protection in Germany and Europe is DIN EN 1176 (Playground equipment and playground surfacing), supplemented by DIN EN 1177 (Impact-absorbing playground surfacing—Determination of critical fall height). These standards define terms, test methods, minimum requirements, and documentation obligations. They are not legal regulations in the strict sense, but have the status of recognized technical rules. Anyone who deviates from them bears the burden of proof in the event of an accident to demonstrate that the chosen solution is equally safe. Compliance with these standards is practically mandatory for public playgrounds, daycare centers, and schoolyards.

In addition to the DIN EN standards, the accident prevention regulations of the statutory accident insurance institutions are relevant, in particular DGUV Rule 102-007 (formerly GUV-SI 8017) for daycare centers and schools. These regulations specify operator obligations, inspection intervals, and documentation requirements. Planners should always keep both levels in mind: the product-related standard for equipment and flooring on the one hand, and the operator-related regulations for inspection and maintenance on the other.

The critical fall height: a key concept in fall protection planning

The critical fall height (CFH) is the central design criterion for impact protection on playgrounds. It describes the maximum height from which a child can fall onto the playground surface without the impact exceeding a head injury threshold. This threshold is measured in the testing procedure according to DIN EN 1177 as the HIC value (Head Injury Criterion): An HIC value of 1000 is considered the threshold above which the risk of severe brain injuries increases significantly. The critical fall height is therefore not a fixed number, but rather a result of material testing: Every impact protection surface has a specific critical fall height, which is determined through standardized drop tests using a test specimen.

For planning purposes, this means: First, the free-fall height of the play equipment is determined. The free-fall height corresponds to the vertical distance between the highest accessible point of the equipment and the ground below. This value must be less than or equal to the critical fall height of the chosen impact-absorbing surface. A climbing tower with a platform at a height of three meters therefore requires a surface with a critical fall height of at least three meters. If this requirement is not met, the playground does not comply with regulations, regardless of how attractive the equipment is designed.

A common misconception in practice is to equate the free fall height with the overall height of the equipment. The decisive factor is always the highest point a child can reach as intended—platforms, ladder rungs, climbing holds, and similar elements—not the overall structural height of the equipment. At the same time, it is important to note that equipment with a free fall height of less than 60 centimeters does not require a separate impact-absorbing surface according to DIN EN 1176, provided the existing floor does not present additional hazards such as edges or hard surfaces. However, this threshold does not mean it is acceptable to use hard surfaces under small pieces of equipment, as children can also fall awkwardly from low heights.

Comparison of impact protection materials: loose materials, mats, and bonded systems

The range of impact-absorbing surfaces can be divided into three main categories: loose bulk materials, prefabricated slabs and impact-absorbing mats, and bonded elastic surfaces. Each category has specific strengths, weaknesses, and conditions of use that must be carefully considered during the planning phase.

Loose bulk materials

Sand, wood chips, bark mulch, and gravel are among the oldest and most widely used impact-absorbing materials on playgrounds. Their effectiveness is based on energy absorption through the deformation and compaction of the material upon impact. Sand is the best-known material, but it offers a comparatively low impact protection height per unit of installation depth: To achieve a critical fall height of three meters, an installation depth of at least 30 centimeters is required, with the actual protective effect depending heavily on the grain size distribution, moisture content, and degree of compaction. Dry, loosely installed sand offers significantly better protection than wet, compacted sand. Regular loosening is therefore not merely cosmetic, but a safety-related maintenance measure.

Wood chips and bark mulch offer a higher critical fall height than sand at the same installation depth; they are lighter and less prone to compaction. However, they have the disadvantage of being organic materials that decompose, can promote mold growth, and provide habitat for insects and small animals. While the latter is not inherently negative from an ecological perspective, it can raise hygiene concerns in heavily used play areas. Bark mulch certified according to DIN EN 1177 has a defined particle size and composition that differs from standard garden mulch. Planners should explicitly insist on the use of products compliant with the standard and include this requirement in the specifications.

Gravel is less commonly used as a fall protection material, but it makes sense in certain contexts—for example, when the design of a playground calls for a natural aesthetic. Gravel compacts less than sand, is highly permeable, and is easy to maintain. With the appropriate grain size and sufficient installation depth, its impact protection meets standards. Disadvantages include the risk of injury from individual stones during falls and the tendency for children to step outside the impact protection zone.

Fall Protection Tiles and Rubber Mats

Prefabricated impact-absorbing tiles made of rubber granules or polyurethane-bonded cork are a widely used alternative to loose-fill materials, especially in heavily used or accessible play areas. They offer a defined, consistent level of protection, are wheelchair accessible, and do not require regular replenishment of loose fill. The critical fall height is tested and documented for each product, simplifying the planning process. Typical tile thicknesses of 40 to 100 millimeters cover critical fall heights of approximately 1.5 to 3 meters, depending on the material’s density and composition.

Disadvantages of rubber mats include higher purchase costs compared to bulk materials, limited repairability in case of damage, and environmental concerns regarding the production and disposal of rubber granules, which are often derived from recycled tires. Newer developments utilize natural rubber or cork-based systems, which have a more favorable environmental footprint. In practice, rubber mats show wear at the edges and seams under heavy use, requiring regular inspection and replacement as needed, since raised mat edges themselves can pose a tripping hazard.

Bonded impact protection surfaces

Bonded elastic surfaces, also known as artificial turf with impact-absorbing underlay or impact-absorbing synthetic surfaces, are installed on-site and form a seamless, water-permeable surface. They are particularly popular in schoolyards and heavily used play areas because they are durable, easy to maintain, and visually appealing. Their protective effect stems from the combination of surface thickness and material elasticity; here, too, product-specific testing in accordance with DIN EN 1177 is required. Bonded surfaces can be colored and integrated into play areas, opening up design possibilities.

However, bonded systems are subject to thermal stress in hot weather: Dark rubber surfaces can heat up to temperatures in summer that are problematic for small children upon direct skin contact. This aspect is gaining increasing importance in the context of urban heat island effects. Light colors and the integration of shading elements are planning solutions, but these are not always sufficient. From an urban ecological perspective, bonded paving also seals surfaces, which promotes neither infiltration nor biodiversity. Planners should consider whether its use should be limited to the immediate impact protection zone or whether loose-fill materials represent a more ecologically sound alternative.

Fall protection zones: sizing, demarcation, and overlap

The fall protection zone is the area around playground equipment that must be equipped with suitable impact-absorbing surfacing. Its dimensions depend on the type of equipment, its height, and the potential trajectory of a falling child. DIN EN 1176 specifies minimum distances for various types of equipment, measured from the outer edge of the equipment. For equipment with a free fall height of up to 1.5 meters, the minimum distance is generally 1.5 meters; for greater fall heights, this value increases accordingly. Swings require particularly generous fall protection zones due to the potential forward and backward trajectory of a child, the size of which is determined by the suspension height and the length of the swing ropes.

Overlapping fall protection zones for adjacent equipment are permitted, provided the equipment cannot be used simultaneously in a way that would cause children to collide. This condition is difficult to guarantee in practice and should be avoided during the planning phase by ensuring sufficient distance between equipment. Particular attention should be paid to demarcating the fall protection zone from hard surfaces such as asphalt, paving stones, or concrete. Edging stones, lawn edges, or changes in surface material immediately at the boundary of the fall protection zone are potential tripping and impact hazards; the transitions must be flush and free of sharp edges.

In practice, it is frequently observed that fall protection zones shrink over time: loose material is compacted, edging shifts, and lawn edges encroach. Regular visual inspections, as required by operator regulations, must record and document these changes. A fall protection zone that is correctly dimensioned on paper but has been reduced to half its depth in reality due to material loss no longer provides the required level of protection.

Installation Depths, Maintenance, and Operator Responsibilities

The protective effect of bulk materials depends crucially on the actual installation depth. DIN EN 1177 specifies minimum installation depths for various materials and critical drop heights. These values apply to freshly installed, loose material; the effective depth decreases during operation due to use, weathering, and compaction. Planners should therefore specify an installation depth exceeding the minimum value to provide a buffer for settlement and compaction. For sand with a critical drop height of three meters, experts recommend an installation depth of at least 35 to 40 centimeters, although the standard value is 30 centimeters.

The operator’s responsibilities for playgrounds are divided into three stages: daily visual inspection (for heavily used facilities), regular operational inspection (generally monthly), and an annual main inspection by a qualified person. Specifically regarding impact protection, this means: The visual inspection identifies obvious defects such as foreign objects in the fill material, heavily compacted areas, or damaged paving slabs. The operational inspection measures and documents the installation depth. The main inspection includes a complete assessment of the impact protection’s effectiveness, potentially with recommendations for refilling or material replacement.

Foreign objects in the loose fill material are an underestimated risk: shards of glass, stones, metal parts, or animal excrement can impair its protective function and pose their own injury hazards. Regular sifting or raking of the loose fill material is therefore mandatory, not optional. In the case of sand, it is also important to consider that it is attractive as a play material and is carried by children from the impact-absorbing zone to other areas, which locally reduces the installation depth. Edging made of wooden planks, steel, or concrete limits material loss but can itself become a hazard if it protrudes or has sharp edges.

Common Planning Mistakes and How to Avoid Them

One of the most common mistakes in practice is underestimating the free-fall height. Planners sometimes base their calculations on the overall height of a piece of equipment or on manufacturer specifications that do not take all accessible points into account. A careful on-site measurement check after installation is essential, as installation tolerances and unevenness in the floor can alter the actual free-fall height compared to the planned value.

Another common mistake is the use of materials that may appear to provide impact protection but have not been tested in accordance with DIN EN 1177. Commercially available garden mulch, decorative gravel, or play sand without a test certificate do not necessarily meet the requirements. Planners and clients must insist on delivery with a test certificate and declaration of conformity and keep these documents in the operator’s records.

Accessibility and fall protection are often perceived as contradictory in planning. Loose materials are difficult for wheelchair users and children with mobility impairments to navigate, while hard surfaces compromise fall protection. The solution lies in differentiated zoning: access routes and waiting areas are designed with accessible, solid surfaces; the actual fall protection zones beneath equipment are covered with bulk materials or certified rubber mats. This combination complies with standards and is aesthetically pleasing, but requires careful planning from the outset.

Finally, the thermal stress on dark, impact-absorbing surfaces is often overlooked in the planning process. Black rubber tiles or dark gray plastic surfaces can heat up to temperatures in summer that are dangerous for small children upon direct skin contact. Shading from trees or sun sails, light-colored surfaces, and the selection of materials with low heat absorption are planning solutions that are gaining importance in the context of urban climate adaptation.

Fall protection in the context of playground planning, urban ecology, and climate adaptation

Impact protection on playgrounds is not an isolated safety feature, but rather part of an integrated open-space concept. The choice of impact protection material influences the impermeability, infiltration capacity, microclimate, and biodiversity of a play area. Loose materials such as wood chips or sand are permeable, thermally more favorable than rubber surfaces, and provide habitat for soil organisms. Bonded surfaces are impermeable, thermally stressful, and less ecologically valuable, but indispensable in certain usage contexts.

Within the framework of the “sponge city” concept, which is being integrated into open space planning in many German cities, the permeability of playground surfaces is gaining importance. Loose-fill materials with an open-pored substructure can absorb significant amounts of rainwater and release it gradually, thereby relieving the burden on the sewer system. Planners who consider impact protection and rainwater management together can transform playgrounds into multifunctional open spaces that combine safety, play value, and ecological performance.

Natural playgrounds, designed with natural materials such as tree trunks, boulders, and mounds of earth, place special demands on fall protection because free-fall heights are often difficult to determine and the equipment does not conform to standard designs. DIN EN 1176 provides guidance for natural play areas but allows for some interpretation. Expert planners familiar with these types of playgrounds can develop solutions that comply with standards while preserving the character of natural play areas without compromising safety requirements.

Fall protection on playgrounds is ultimately a cross-cutting issue that combines knowledge of standards, materials science, ecological understanding, and sound planning judgment. Those who master this discipline create play spaces that give children genuine freedom because they are safe enough to allow for risks and robust enough to withstand everyday use. That is the real goal: not a risk-free playground, but a cleverly planned, standards-compliant, and carefully maintained space where children can fall without being seriously injured.

COP15: World Conference on Nature

Building design
By 2030, 30 percent of land areas and the oceans are to be given protected status.

The COP15 calls for

The 2021 COP15 World Conference on Nature took place in the Chinese city of Kunming. 200 parties to the UN Convention on Biological Diversity (CBD) took part in the week-long event. Read everything you need to know about the event here.

In October 2021, the World Conference on Nature, COP15, took place in the Chinese city of Kunming. 200 Parties to the UN Convention on Biological Diversity (CBD) took part in the week-long event. Read everything you need to know about the event here.

The first part of the 15th Conference of the Parties to the Convention on Biological Diversity (CBD COP15) took place, one year late, from October 11 to 15, 2021, in Kunming, China. During this time, the almost 200 Parties to the Convention drew up a preliminary framework agreement in online conferences. It will then be negotiated and adopted in April and May 2022 during a face-to-face event.

What had already become apparent at COP13 in 2016 and at COP14, which followed in 2018, finally became clear at the COP: the 20 targets that the Parties set themselves for 2020 at COP10 in Aichi, Japan, in 2010 – the so-called “Aichi Targets” – were for the most part clearly missed. For example, forest areas worldwide are still declining at a rapid rate – in stark contrast to Aichi target number five, according to which the rate of loss should be reduced by at least half. Compared to 2010, the rate of loss has even increased by more than 27 percent in 2020, as an analysis by Global Forest Watch on the decline of global primary forest shows.

According to the COP15 draft, at least 30 percent of land and oceans are now to be given protected status by 2030. This “30×30” issue was one of the key points discussed during COP15. The German government delegation, led by Federal Environment Minister Svenja Schulze (SPD), also named the 30 percent target on land and in the sea as one of the three main topics with which Germany entered the conference at the start of the event. The German delegation is also campaigning for concrete reduction targets for eutrophication and plastic waste as well as for the renaturation of destroyed ecosystems.

Schulze summarizes the position of the German government as follows: “Never before in the history of mankind has our planet irretrievably lost so many species in such a short space of time. On average, one species disappears every ten minutes. The loss of biodiversity has also long had serious economic consequences. In this critical situation, the world is coming together to pave the way for a new global agreement that will put a stop to the destruction of ecosystems and the loss of species. The World Conference on Nature is an opportunity for a new start. It is no longer enough to place individual species or areas under protection. After decades of nature destruction, we must reverse the trend and initiate a decade of renaturation.”

By way of comparison: in 2019, only 15 percent of global land and inland water areas and 7 percent of the oceans were protected, according to a study by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). Expanding these areas to 30 percent within less than ten years is a noble and necessary, but also rather ambitious project, especially in view of international conflicts of interest.

It is also not entirely clear from the draft COP15 framework that has now been drawn up what exactly this “30 percent” is supposed to mean. There is plenty of room for interpretation. Does it mean 30 percent of the Earth’s surface? Or actually 30 percent of the oceans AND 30 percent of inland areas? Should each country protect 30 percent of its individual national territory and, if not, what would a sensible distribution look like? These are all questions that remain unanswered after the first part of COP15.

The question of the type of protected areas is equally unclear. There are no requirements in the draft regarding the quality of a nature reserve. Critics fear that areas with low conservation value could be declared as protected areas just to meet the numbers.

The COB15 draft is therefore still relatively vague and there is a great need for negotiations on the second round from April 25 to May 8. Even then, however, the draft framework will not be legally binding. It has always functioned more as a kind of proposal that the states can adhere to or not. Ultimately, the decisive factor will be how important the protection of biodiversity is recognized in the individual countries of the global community.

You can find out more about CBD COP15 on the CBD website.

Also interesting: The consequences of climate change are becoming more and more apparent worldwide. You can read about the acute dangers this poses for the world-famous Great Barrier Reef in Australia here.