Types of Playing Fields

More in this section

• Hybrid grass
• Innovation
• Performance and safety
• Resistance and durability
• Ecology and savings
• A forward-looking choice
• Types of Playing Fields
• Resistance and durability indices
• Precautions
• FAQ 01 Key Features
• FAQ 02 Application Areas
• FAQ 03 Comparing Savings
• FAQ 04 Market Demand
• FAQ 05 Duration Comparison
• FAQ 06 Comparing maintenance processes
• FAQ 07 Multidisciplinary Fields
• FAQ 08 Water Consumption
• FAQ 09 Frost and Heat Resilience
• FAQ 10 Innovative Value

Natural, reinforced, natural hybrid, synthetic hybrid or synthetic. These are the five types of fields developed over the last few years according to FIFA. Let's delve into some details and consider the real advantages between one type and another.

Summary

The merits of natural grass with synthetic reinforcement

In the pursuit of increasingly high-performing surfaces, in times when stadiums are used multiple times a week providing challenging conditions for the growth of natural grass, several innovations have hit the market. In addition to traditional natural grass and third-generation artificial turf, the popularity of a new generation of playing surfaces is growing: those often simply referred to as hybrid systems which actually involve various combinations of materials and construction types. So, following FIFA's document on the subject, let’s provide an overview of the various types of sporting surfaces used in football, with some guidelines on the technical aspects and performance, including the innovative POWERgrass hybrid system.

The type of playing fields according to FIFA

Given that many different terms are used to qualify surfaces as "hybrid," "reinforced," "mixed," the following table aim to provide a clearer overview of the different categories, placing them in the natural-synthetic continuum. The table should be understood as a generalization of current products. With the evolution of innovations and technologies, updates to the classifications may be necessary. Indeed FIFA proposed the following classification in 2017:

Classification of the playing field - FIFA 2017

The differentiation is made based on the organic/inorganic nature of the materials used, the impact of the materials on the final product, and the typical maintenance required for each category. Natural grass is a living organism that can grow and regenerate, while synthetic grass does not.

1. The category "natural grass turf" comprises all cultivated or laid grass surfaces that do not include other materials.
2. "Reinforced surfaces" include additional support in the construction of the root zone, with the aim of strengthening the grass's hold. For the user, the surface does not appear different, as it is effectively only natural grass.
3. "Hybrid natural surfaces" are those most commonly referred to when using the term "hybrid". They are natural surfaces grown within a base of synthetic fibres. The synthetic fibres are visible, but normally constitute less than 5% of the total grass coverage, which is why these surfaces are classified as "natural".
4. "Hybrid synthetic surfaces" are based on artificial turf with sand, but can use natural organic materials such as so-called performance infill (typically in place of rubber infill). This category is considered a synthetic surface as it essentially requires the maintenance of an artificial grass field.
5. "Synthetic surfaces" are made up of artificial materials (products or manufactured by humans), typically an artificial grass carpet, a sand infill and a rubber infill with the potential addition of a shock-absorbing underlay.

Note well: hybrid grass systems, for the purposes of approval, belong to the playing field category of natural grass.

The substantial differences between hybrid systems

With the development of innovative technologies, a further classification is possible because the choice between various hybrid systems and the method of installation can significantly influence the usability of the field during the week, the costs of implementation and maintenance and the possibility to renew the system multiple times, therefore, also its duration. For example, between an in situ injected vertical hybrid system, a transplanted in-sod horizontal hybrid system, and an in situ installed horizontal hybrid system, there are so many variables that can easily constitute three subtypes of natural hybrid fields.

the differences between hybrid systems

3.1 In the case of the natural vertical hybrid system, there is no support for the roots to cling to. The system requires a special machine for installation and the hold of the fibers to the soil depends on the consistency of the sand layer and depth of operation. Usually, the fibers are planted at a depth of 18 cm and form a very solid surface. During play, fewer holes are formed on the surface, but the ground tends to harden quickly. Post-game restoration and frequent spiking are required to keep the surface softness within the optimal range of 65-85 g with a Clegg hammer. The difference between one vertical system and another is determined by the quality of the fibers and their number per square meter, which usually hovers around 2500 points per square meter.

3.2 In the case of the natural horizontal hybrid system, it includes all types made with artificial carpets with an open horizontal support, easily penetrable by roots that anchor to it. The fibers must be welded to the horizontal support in the factory with a force superior to 30 N. The difference between one system and another pertains to the type of support, the quality of the fibers and the number per square meter, which should not exceed 5% of the surface, to leave ample space for natural grass. We will not delve into the technical details between one system and another, but we can make a major distinction for those transplanted in the field in large turfs. This type of installation necessarily implies a cultivation period in the nursery between three and six months. Often, hybrid turfs are grown far from the final installation field, which requires adaptation to a different climate. In any case, special machinery, numerous means, and meticulous organization are needed for the collection, transportation, and laying of hybrid turfs. Moreover, the transplant itself is a great stress for the lawn, which creates more thatch, while the differences between turf junctions often require reseeding and sanding that tends to bury the synthetic fibers. In the phase of natural grass renewal (necessary at most every 3 years) the operation is complicated, if not impossible, to remove the natural grass without lifting the artificial one or damaging the synthetic fibers.

3.3 In the case of the natural horizontal hybrid system with in situ installation, however, these problems occur less because the rolls of artificial grass with open support are sewn together. Many believe that the grass should grow for at least 6 months to reach the right maturity. However, thanks to an optimized cultivation method, it is possible to provide a ready-to-use horizontal hybrid turf within 4 weeks from sowing, a period consistent with the summer break of the game. In the case of fields for intensive use, by favouring systems with a higher number of fibers, it is possible to have a consistently playable field even during the winter and then schedule the resowing in the ideal growth season. The sewing of the rolls together allows the system to be easily renewed every 2 or 3 years without damaging the fibers or lifting the artificial grass, thus providing a field that can last over 20 years like the POWERgrass field

4.1 and 4.2 In the case of synthetic hybrid systems and synthetic hybrid refill systems, it must be clarified that in neither case do we have natural grass except when weeds grow. The main difference between the two is that the former has two types of infill: stabilizing infill (dried sand) and infill with natural organic grains. Both infills need to be removed when replacing the system at the end of its lifecycle and potentially recycled for other uses. The synthetic hybrid refill system instead, does not use sand to stabilize the artificial turf because the performance infill is heavy enough to perform both functions. In this case, the infill can be partially reworked, cleaned and reused at the end of the artificial grass life cycle.