The Artificial Turf System and Its Components

A comprehensive system that is finely tuned from a building physics standpoint and optimised in its individual components ensures the artificial turf system can be used optimally and consistently provides good playability. Typically, this system consists of the artificial turf surface, infill granules, and an elastic base layer over gravel or an elastic layer over asphalt. With the correct combination, they guarantee the desired playing characteristics as well as durability and longevity. Specifically, the elastic layers contribute to player protection, force reduction, and preservation of playing characteristics. Therefore, high quality should also be considered for the artificial turf sub-base.

Non-compliance with standards threatens grants, warranty and increases accident risk

When constructing playing fields with artificial turf, the DIN EN 153301:2013-12 standard applies. Failure to build according to standards not only endangers the warranty but also the payment of public subsidies. A compulsory definition includes the use of a bound base layer, either a bound elastic base layer on a substructure with gravel or an elastic layer on a bound base layer (asphalt). Shockpad rolls on gravel do not conform to the standard.

Quality of artificial turf sub-base influences protection functions and playing characteristics

Beneath the actual artificial turf, there must be a so-called elastic layer. This varies depending on the surface - whether asphalt or gravel - and usage. It is responsible for optimal playability, and its quality influences the long-term force reduction and playing characteristics like ball reflection or rebound behaviour. It also ensures the levelness of the pitch and minimises accident risk. Therefore, special attention should be paid to the choice of the elastic layer and its precise installation. Incidentally, when installing new artificial turf, this layer can usually be retained – the sub-base typically lasts three to four generations of artificial turf.

Bound elastic base layer (ET) or elastic layer (EL)?

The Elastic Base Layer (ET) is one of the bound base layers, with mineral aggregates mixed in. This way, higher strength is achieved; a (unbound) gravel layer suffices as an artificial turf sub-base. The Elastic Base Layer from Polytan meets all requirements of DIN 18035/7:2019-12 and is suitable for (almost) all types of use. Depending on the sport, such as football or hockey, we optimise through the proportion of binder. The ETH (Elastic Base Layer Hockey) 35 mm has a binder proportion of approximately 12%, while for football this is about 8 %.

The desired force reduction with the bound elastic base layer is ensured for decades, which is why it has been one of the most widespread artificial turf sub-bases in Germany for over 35 years.

The Elastic Layer (EL) is used when building with an asphalt base layer – especially with unstable ground or in high-performance hockey sports: The combination of asphalt and a 15 mm elastic layer under the artificial turf ensures absolutely ideal ball bounce behaviour in hockey – the ball bounces less and stays closer to the ground. A particularly sustainable elastic layer is PolyBase GT from Polytan, which combines recycled materials with an environmentally friendly binding agent. PolyBase GTR consists of 100% recycled material from the elasticising predecessor layer, which is removed on site and reused.

Requirements of the international guidelines of sports associations

Initially, for the construction of artificial turf fields, DIN EN 15330:2013-12 applies.

Implementation options:

• bound elastic base layer of 35 mm on an unbound base layer (gravel)  – manufactured on site
• elastic layer ˂35 mm on a bound base layer (asphalt) – manufactured on site or prefabricated (laid flat and without joints at the edges)

For our elastic layers, we use only high-quality, quality-monitored and environmentally tested ELT (End-of-Life Tyres) rubber granules and special Polytan PU binder. They are individually tailored to each sport by our specialists with their force reduction values and sport-specific characteristics. They also meet the different requirements of sports associations such as FIFA, FIH, and World Rugby.

Advantages of Polytan's elastic layers:

• Use of ELT (End-of-Life Tyres) Rubber Granulate
• No surface sealing
• Long durability
• Optimal player protection
• In-situ installation (on-site construction)

Recycling

• Rubber granules made from 100% post-consumer recycled material
• European quality-tested granules, according to REACH
• Recyclability and direct reuse

Sustainability

• Polytan PU binder saves CO2
• Lifespan over 35 years
• Positive environmental balance compared to elastic layers made from new materials

Health and Environment

• Strictest testing regarding soil and groundwater compatibility
• Perfect player protection through permanent elasticity
• Avoidance of surface sealing due to permeability to water

In-situ Installation – Seamless and Absolutely Flat

On-site (in-situ) installation involves mixing the components of the elastic layers directly on site and installing them precisely with a paver according to specified thicknesses. This construction method ensures that an absolutely flat surface is created with defined slope angles. Thus, site-permissible irregularities of the unbound base layer (gravel planum) or in the asphalt can be levelled out. Only through on-site installation can a seamless connection between the always necessary artificial turf strips for a sports field be established, avoiding the formation of waves and gaps. At the same time, this installation is particularly high-quality and durable – the usage duration of the outdoor facilities is significantly increased.

Advantage over rolled goods/Shockpads

If built according to standards, rolled goods or shockpads always require a bound base layer (asphalt). Generally, the asphalt surface is not even and rolled goods cannot compensate for these unevennesses. Furthermore, there are seams and joints, which can open and form gaps. If rolled goods are laid on gravel, it is not only dangerous but also contrary to the applicable DIN standard – which endangers both public funds and warranty. While rolled goods initially seem cost-effective, they do not last as long as an elastic layer of rubber granulate. Additionally, they are usually made from new materials, another disadvantage from an ecological perspective.

Rubber granules from 100% recycling material

Our elastic layers use only high-quality, quality-monitored, environmentally-tested ELT (End-of-Life Tyres) rubber granules (SBR) and a special PU binder. An aggregate is also added for the bound elastic base layer. The encapsulation of the rubber granules with polyurethane binder encloses all components of the SBR granulate or the recycled material. The recycled material is available everywhere in Europe without long transport distances and meets all requirements of the REACH directive and the corresponding PAH concentration limits. With every tonne of ELT granulate that is recycled rather than burnt, environmental pollution from CO2 emissions decreases by at least 700 kg – a significant contribution to conserving resources and our environment.

Permanent elasticity and player protection

Unique in sports functionality, our elastic layers provide elasticity values that ensure lasting player safety: Even with an extreme displacement of infill materials or a completely worn artificial surface, force reduction and deformation remain optimal. This helps prevent overuse of joints, tendons, and ligaments.

Optimal drainage and environmental properties

All elastic layers from Polytan are permeable to water. Due to their consistently reliable artificial turf drainage properties, the field can be used unrestrictedly even during heavy rains. At the same time, they make a valuable contribution to avoiding surface sealing.

A seamless quality control according to strict guidelines for soil and water or RAL GZ 944/2 further monitors environmental compatibility.