On the way to the Monte Rosa hut near Zermatt

Building design

Spending the night at 2,883 meters. Matterhorn and Monte Rosa hut in the early morning light. Photo: Iain Aitchison

For architecture-loving mountain enthusiasts, a visit to the Monte Rosa hut near Zermatt is at the top of the list. A new access route over the glacier has now also been built.

For architecture-loving mountain enthusiasts, a visit to the Monte Rosa hut near Zermatt is at the top of the list. A new access route over the glacier has now also been built.

To say it straight away: because of the longer glacier passage, it is still advisable to take crampons and rope, and preferably a mountain guide too. But there is no comparison with the old hut trail, which, despite ladders and chains, became increasingly difficult due to the melting Gorner glacier and also had to be constantly repaired. In contrast, the new “Panoramaweg” now leads much higher up over the mountain flanks with magnificent views. It is well marked and secured where it gets dicey.

Like many mountain lodges, the Monte Rosa hut has a history stretching back over a hundred years. Formerly known as the Bétemps hut and located at a lower altitude, the old stone building from 1895 was rebuilt several times. One of the reasons for a new building was the 150th anniversary celebrations of ETH Zurich, which selected this project as one of 50 anniversary projects. Today, the new hut is a work of the 21st century: five storeys high, built on an irregular octagonal base, it was completed by ETH Studio Monte Rosa and Bearth & Deplazes Architects in 2009. The people from ETH and the Swiss Alpine Club developed the concept together over a period of six years. The aim was to test new technologies in design, calculation and production in the high mountains. The energy and building technology, for example, is designed to function as self-sufficiently as possible: with a ventilation system and heat recovery, water tank and mini sewage treatment plant for cleaning waste water as well as photovoltaics for electricity; heat is provided by solar collectors and there is also a mini combined heat and power plant powered by rapeseed oil for bad weather.

However, the building is particularly worth seeing because of its architectural design in the shape of a rock crystal. In order to keep the CO2 footprint during construction within limits, the decision was made to mainly use the lighter building materials wood and aluminum, as everything had to be delivered by helicopter. The primary construction consists of prefabricated frame elements that are open on the room side, while the shell was insulated with 35 centimetres of mineral fiber and fitted with a rear-ventilated aluminum standing seam roof.
Despite the bunk beds, the accommodation is comfortable compared to some other huts: there are new, soft mattresses, coin-operated hot showers and toilets inside the building, as well as triple glazing so that you can enjoy the view of the Gorner Glacier and Matterhorn in the distance with your nose close to the window without freezing. The striking ribbon of windows that wraps around the façade illuminates the polygonal living room and the staircase to the sleeping areas. The construction remains clearly visible, especially in the living room: Here, the thick timber trusses are very reassuring to guests when a storm is brewing outside and the wind is whistling around the corners. Not only the construction parts, but also the wooden tables and benches were precisely fitted using CNC-manufactured components, as were the bunk beds and shelves in the bedrooms. This saved money, as the window of opportunity for good weather between May and September 2009 had to be used optimally.
The planning of the hut at 2,883 meters was accompanied by 33 students from several semesters of the Department of Architecture at ETH Zurich over a period of six years – and they certainly learned a lot about construction, shell and supply in extreme conditions.

You can find the article about the Monte Rosa hut near Zermatt in our current Baumeister issue 02/2019.

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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.