Stay Ahead Of The Game
By Thomas P. Shay
Most people have a good understanding of the benefits that synthetic turf can provide—primarily that it can take a beating. But once it has been determined that a synthetic-turf field needs to be replaced, the next step is actually getting it done. The situation has likely changed for the better since your field was first installed a decade or more ago. The athletic-field industry and the synthetic-turf segment, in particular, have evolved significantly over that time, as have the design considerations that need to be contemplated during replacement.
Over the past several years, advancements have been made across the board with new turf fibers and fiber combinations, new infills, new shock pads, and drainage layers. To get the highest performing and safest system you can afford, here are some of the most important design criteria to evaluate. Many of these items are interrelated, making a thorough investigation and design that much more critical and impactful.
Working From The Ground Up
When replacing an existing field, one of the first considerations is how to remove what’s already there in a responsible way. Maintaining synthetic-turf fields are often more sustainable than natural-grass fields:
- They save water and chemicals
- They significantly reduce the use of fossil fuels for activities like mowing and aerating.
But the responsibility of environmental awareness shouldn’t stop at the end of the turf’s functional life. For synthetic turf to really be an environmentally respectable alternative to natural grass, the materials used must be recycled. A prescriptive method is clean, efficient, and safer for the base, and ensures the field components are suitable for recycling and transport. The ideal way to do this is to hire a company that specializes in this type of synthetic-turf removal that will make sure the carpet is removed in sufficiently sized strips to be transported and repurposed or recycled, and that the infill components are separated for appropriate management. Using this method, up to 95 percent of the materials in a synthetic field can be recycled or repurposed.
At this point in the process—or earlier if possible—conduct a thorough assessment of the existing field base that will be used as the foundation. An evaluation of the existing stone base condition and its performance is critical, especially from a planarity and infiltration capacity standpoint. One can spend a lot of capital on the newest synthetic-turf system, but it will be short-lived if reinstalled without necessary provisions over an underperforming base. This goes for stone bases as well as fields that include a shock pad on the initial installation. Depending on the type of pad installed, there will be different ways to investigate the adequacy for reuse and retrofit for replacement.
Environmental And Field-Use Considerations
For many years, crumb rubber with or without sand was one of the only—if not the only—accepted option for synthetic-turf infill. Now, coupled with the demand for continuous improvement and innovation from within the industry are questions and perceptions surrounding crumb rubber’s safety, as well as best practices for preventing concussions and traumatic brain injury, given their prevalence in several sports. Fortunately, there are more choices for field owners today than ever before, providing the opportunity to balance safety concerns with the requirements of the activities the field will be primarily used for. While this innovation and rapid development are generally viewed positively, they need to be managed appropriately to be sure products and suppliers are providing materials that perform as intended with a strong track record, and that field system components are compatible.
In addition to crumb rubber, some viable alternative infills include organic infill with options such as coconut husk, cork, and nut shells, coated sand, and virgin- and coated-rubbers or plastics, which can all be implemented to customize a field. A field can be designed to be firmer and faster, yet still have leading impact attenuation properties, or can be designed to be slower or cater to more realistic ball bounce and ball speed for sports such as baseball and soccer, which are heavily dependent on ball-surface interaction. It is also possible, upon evaluation and confirmation, to reuse the existing infill, leading to potential cost savings in addition to the environmental benefits of reducing or delaying disposal and trucking.
A perfectly customized field, though, can still run up against significant challenges if a design does not take into account the need for appropriate drainage. Drainage issues can have a substantial impact on the performance of a field, so providing for an effective system is crucial in the design process. If you’re replacing a field that has had ponding during rain events, understanding what is happening is critical in designing a new system that will contribute to optimal performance and the longevity of the field. An effective system will allow for surface and internal drainage and will incorporate a subsurface drainage system. Building redundancy into the field system—allowing for multiple lateral- and vertical-drainage ways—is beneficial if unexpected issues arise, such as a breakdown of the field-leveling stone during initial and subsequent installation that will render the stone base impervious or severely lacking in vertical-drainage capacity. While this might be costlier initially, it will eliminate the need to over-excavate and replace an underperforming base on subsequent field replacements.
While there are several views on the best way to drain a synthetic-turf field, most qualified designers agree that the perimeter collector drainage is of utmost importance, and is the most critical aspect of the subsurface drainage system to collect and convey stormwater. The requirements of this type of system are largely dependent on the field base and its performance. When was the last time the collector drainage manholes were opened and inspected? Chances are high that the answer is never, with now being the right time to do so. Depending on the level of investment and upgrades, it may be necessary and prudent to video inspect the subsurface collector pipe system to verify performance.
Replacement Schedule
The timing of turf installation, particularly as it relates to seasonal weather conditions and fluctuating temperatures, is likely not what first comes to mind when planning a replacement. Colder regions and those with greater daily temperature fluctuations can expect more thermal expansion and contraction of the turf-system components, which move at different rates and distances depending upon the materials being used. Additionally, some seaming methods (i.e., adhesive, sewing) and edge-attachment techniques will perform better in certain climates and weather conditions. This should be considered as many replacements occur outside of the prime construction season in varying climates around the country. Turf in northern Maine is going to react differently than that in southern Texas. If an off-season or less-than-ideal weather installation is required, the designer can work with the various material suppliers and installers to generate a design for the greatest probability of success and longevity.
While this article is not an exhaustive list of all of the various design factors that come into play for a new field or a replacement, the points mentioned here will put you on the right track toward a well-made system that will save money or help to get more for your money. The necessary investigations and design should be as complete as possible in the early phases of the project, which will result in a clear scope of work and expectations for all stakeholders. This can often mean building more time into the project schedule at the planning phase, and while this can be a challenge for those excited to get moving on a new field, completing this with due diligence almost guarantees a better end product to enjoy for years to come. After making the choice to replace a field and identifying the funding source, be sure to critically observe and document the field’s performance over its final service period. This information will be more valuable to the designer than you realize.
Thomas P. Shay is a technical manager at Woodard & Curran, an integrated engineering, science, and operations firm. He is a licensed professional engineer specializing in athletic-field and recreation-facility design, and a former college athlete. Reach him at tshay@woodardcurran.com.