March 24, 2009 By Francois Hebert Landscape Architect DSSS ltee.
The 2009 Ontario Turfgrass Symposium, held last February in Guelph, marked the start of a new era on the Canadian sports turf scene. To my knowledge, this was the first time that the synthetic turf phenomenon was officially recognized by the turf industry with the presentation of a one-hour talk on the subject by a dedicated synthetic industry representative.
Knowingly or not, by including this topic in their program, the organizers effectively acknowledge the existence of this technology as well as its pertinence on the sports turf management scene. Past experience teaches us that once this threshold is crossed, there is no turning back and it is time to start taking this seriously.
Synthetic sports fields are complex systems
When considering the building of a new synthetic sport surface for a community or school, it is important that this be approached as a whole integrated system, and not just as a set of distinct components. It is very easy to focus on the actual “carpet” that will be laid out, since it represents what may seem at first glance as the principal part of the project. Invariably, prospective owners of such installations will be assailed by well-meaning playing surface company representatives, all equally motivated by the client’s sole interests and intent on enlightening him on the benefits of their products, and very often on the danger that lies in dealing with their competitors.
Considering the investment involved, it is understandable that the neophyte will be distracted by this and may lose sight of the other systems that need to be put in place so that the finished surface will perform according to planned while lasting for its expected life span.
A synthetic sports turf surface must perform at many levels. Such equipment (which is what this is, same as a pool, gymnasium or arena) must be serviceable rain or shine, cold or hot; it must withstand extreme wear and usage, and it is expected to last for 10 years and more. Such performance characteristics are not solely dependent on the quality of the turf product. The structure on which it is laid is just as important. Failure to see this may result in a finished surface that does not meet expectations.
Hydraulics, mechanics and general engineering
Serviceability in all weather means that when it rains intensely and for long periods, the surface must remain free of standing water, since these surfaces are meant to be usable anytime. Just to give an idea of what this means, one centimetre of rain on a typical football field installation translates into 100 cubic metres of water having to be eliminated, or roughly 22,000 gallons. If it rains steadily and intensely for any length of time, we are talking about huge amounts of water that need to be moved through and out of the system.
Now, unlike natural sports fields, which rely heavily on a combination of surface runoff complemented by some percolation to eliminate water, these surfaces are designed to drain through the surface and out through a drainage system that will be somehow connected to some kind of evacuation network. In other words, the playing surface will generate as much drainage water as an equally sized paved surface. We are talking here of huge volumes of drainage water and very important drainage rates.
This drainage is mostly carried through the surface’s stone base. The water must percolate through the stone and it must reach an underlying drainage system that will then move it out. Some suppliers offer systems that are laid directly under the “carpet” and that allow the water to flow over the stone base. But in most cases, the water has to move through the stone both vertically and laterally towards the drains.
This may seem relatively simple but in reality, this drainage process is compromised by another characteristic that these surfaces must possess, which is their need to maintain their perfect profile or, in other words, to retain their shape. The stone base must be stable and structurally strong enough to be able to support maintenance vehicle traffic over a period of many years without sagging or moving in any way. In our climate, it must also maintain this perfect profile in spite of the problems created by winter frost heave.
What this boils down to is that the stone base on which the synthetic turf is laid must be both structurally stable, have a high load-bearing capacity while providing high drainage performance. Now, this may seem a relatively simple proposition, but the problem is that in a granular base, stability and drainage performance are two competing properties. The more stable a base is, the denser it is and the lower its drainage performance will be. Freer water movement implies more open space in the mass which translates into a less stable structure. A high-performance, well-designed base will provide a surface that will drain well and that will remain “flat” over time. Base failure inevitably results in a playing surface that will wave and warp, or drainage problems will occur, which can be extremely frustrating when you have invested so much money to specifically avoid this. The worst case scenario is when a surface both warps and does not drain well.
This is why a synthetic turf project must be approached as an integrated process, in which the surface cover is but one of the components that needs to be considered.
Synthetic turf – a world of its own
Acknowledging and understanding the complexities of synthetic field base construction is but one of the challenges facing the designer of such projects. The actual synthetic turf covering is another thing altogether. Just as the base presents an interesting challenge, selecting the appropriate turf system is also very important in a process that must provide performance and long term longevity in a surface that is meant to be subjected to high and intense levels of usage.
The catch word here is “system.” There are two ways of approaching these products. One is focus on individual characteristics in order to distinguish between the different brands and products. The other is to consider all these characteristics as complementary components of an integrated system.
There are numerous characteristics that can be considered, each seemingly as important as the others.
If we look at the basic carpet’s components, turf bind, or the fibre’s resistance to traction, is one property that is readily invoked to qualify a product. Fibre density, or the number of different fibres in a given area, is another, the general feeling being that the more there is, the better. In fact, the list of such characteristics can drag on for pages, with each one being touted as being critical to the products’ ultimate quality.
Then there is the backing. Here again, common sense would dictate that the more layers there are, the better the product.
The infill is another component of the system that plays a major role, or so it seems. Here, you have conflicting views. There are the proponents of pure rubber infill, and there are those who claim that it is essential that sand and rubber be used. Then there are the proportions of these components that come into play, and how they are mixed or laid into the base. To further complicate this, there are different kinds of rubber to consider. And if this is not enough, some manufacturers offer infill materials that are not rubber at all.
Taken individually, all these parameters can be weighed and measured, added up and compared. The instinctive reflex would be to deduce that in all aspects, the higher the value, the higher number or quantity a specific brand presents, the better the resulting product will be. This way, the supplier who presents a product whose individual components and properties add up to the highest number should automatically be considered the best, which in turn should make it extremely easy to make sense of the cacophony of sales pitches and to choose the ultimate product.
Unfortunately, it is not as simple as this. If it was, FIFA (The Fédération Internationale de Football Association—the international body governing soccer) would not recognize 23 different manufacturers as qualifying for its quality control and certification program. The reason for this is that FIFA, as well as other governing bodies, have come to understand that the aggregation of all these individual components, characteristics and properties results in different systems that in turn provide a whole different spectrum or properties and performance characteristics.
Bearing this in mind, one develops a whole new outlook on the products that are promoted and offered on the market. No single characteristic will outweigh the others since the overall performance of the system relies on a combination of different elements, carefully arranged in such a way that the system performs as it does. This way, the resulting performance of the system is considered in the overall evaluation.
The information laid out here is not meant to clarify the selection process, but it is meant to help deciders see through the static and confusion that the many conflicting sales pitches create. In order to make sense of all this, we must step back a little and look at this in a more structured and organized way, instead of focusing on individual sales points.
Turf installation is critical
Another parameter that cannot be neglected is installation quality. If it is not installed properly, using the proper tools, materials and techniques, the best, highest-priced product will inevitably result in an underperforming playing surface. We need only consider the scope of such a project to understand this.
Typically, laying out a regulation Canadian football field implies putting in place around 35 rolls of turf.
Each roll is five metres wide, approximately 60 metres long and weighs thousands of pounds. Once laid on the base, the rolls must be assembled, either by glueing on a fibre backing using specialized and very expensive glue, by sewing or a combination of both techniques, all this under ambient weather conditions, including cold, wind and rain.
Typically, the five-yard lines are tufted (“sewn”) into the backing directly at the factory. So, when these huge rolls are assembled, this must be done in such a way that the lines will remain perfectly parallel and that their spacing will be constant throughout. When the last rolls are put in place, the field layout must be perfect, so that all lines are parallel, evenly spaced and that the surface’s overall dimensions are perfect.
All this assembly must be both precise and long—if not ever-lasting. Any error or carelessness in the laying out of the carpet, or any negligence in the assembly can result in a surface that is unsightly, or that can fall apart over time, or both. Correcting this afterwards is virtually impossible.
Once this is done, all the hash marks, lettering, numbers and other graphics must be incorporated into the surface. This can be done in many ways, but suffice it to say that it is a challenge to do perfectly at such a scale.
Then the infill must be incorporated between the carpet’s fibres, or the artificial grass blades. The infill acts as ballast for the carpet, as a structure to keep the blades erect and as a resilient surface on which the players evolve. To do this, the contractor uses a rotating brush that lifts the blades while the infill material is spread out. Subsequent brushing helps incorporate the material between the fibres, after which the process is repeated a number of times until the proper infill depth is attained.
Although this may seem simple, it is actually a very long and drawn out process. It is critical that the finished infill layer be perfectly even throughout the whole surface, which is about 10,000 square metres for a regular football field. We are talking here of laying around 40 millimetres (less than two inches) of material in a perfectly even layer. If the infill depth is uneven, the surface will react differently from one spot to another. If less than needed is put in place, more fibre will “stick out,” which results in accelerated wear of the surface. If the brushing in of the infill is not done well or using appropriate equipment that is specifically designed for this, the fibre can be damaged, which in fact constitutes an artificial aging of the surface.
In the design process of a project, as well as the resulting bidding phase, care must be devoted to the selection of a supplier that will ensure the best possible installation, independently of the product. In the synthetic turf market, it is relatively simple for anyone to secure a distributorship from even the most reputable suppliers. Few of these, especially European and other foreign manufacturers, have the resources to control the installation of their products in Canada or other distant locations. Many sell their products and then disengage themselves from the process. This means that almost anyone can offer state-of-the-art products, with all the bells and whistles of world class marketing tools, without having the resources, competence or commitment to properly install the systems or offer subsequent service.
If the clients fall for such a mirage, he can find himself staring at a very dismal picture indeed.
Synthetic turf – A modern tool to tackle age-old problems
The preceding text is but an elaborate preamble to a very simple conclusion. When we consider a synthetic turf project in a way such as is pictured here, it may appear overly complicated, just as others would like it to appear simple in order to sell their products. The objective of this text is certainly not to draw such a complex picture that the prospective buyers of such systems will be confused or scared away. But it is important that the inherent complexities of this technology not be concealed and replaced by simplistic sales arguments, solely meant to discredit competing products and systems.
There is a wide spectrum of products and systems available on the market. The price range is enormous and the proposed technologies vary from the very basic to the most complex. Sales strategies are either sophisticated or ridiculously simple, depending on the individual products, sales people and clients. There is a wealth of available information which can be confusing at best, especially since there are no certified authorities that can rule on what is true or what is not, what is good and what is bad. Each individual project manager must make sense of all this in order to make the most appropriate decisions that apply to his or her individual needs. To do this, we must develop our expertise, on our own and in partnership with our peers and professional associations.
The Canadian synthetic turf market is at the early stages of infancy. The few projects that are already in place are the work of adventurous pioneers. But as this technology gains in acceptance as a viable tool in modern sports turf management (notice that I did not say “a viable alternative to natural turf” – there is a nuance here that must not be overlooked), the number of such projects will increase dramatically and, over time, the amount of public money invested in these projects will add up considerably. It thus becomes important that those responsible for instigating these projects acquire such a level of proficiency that they can steer them towards positive outcomes.
In this, the recent Ontario Turfgrass Symposium fulfilled its educational mission and proved, by the very inclusion of this controversial topic, that the organizations involved take their responsibilities seriously, while keeping an open mind towards innovation. We lift our hats off to them. The attentive response and pointed questions from the audience demonstrated the level of interest this arouses and the need for further such initiatives.
This is an industry that cannot be guided by prices alone. In a solely price-driven system, it is invariably the project’s overall quality that suffers. This does not mean that only the most expensive systems should be considered. Specific systems are designed to perform following specific parameters.
Costlier, more sophisticated systems are meant to answer very precise needs. For more generalized uses, especially when many sports are to be practiced on a multi-use surface, there are perfectly good lower level systems that can do just as well, at much lower prices. The challenge is to make sense of all this and to tread cautiously.
Construction and bidding documents must be formulated in such a way that low-priced tenders do not solely result in the lowest quality offerings being the only ones put in place. The inclusion of strict performance requirements and the application of strict and professional quality control processes throughout the construction phase are essential if we want to see the Canadian synthetic turf market grow in quality as well as quantity.
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