Non-Watered Hockey Surfaces
The International Hockey Federation (FIH) is pursuing synthetic turf surfaces that have the playing characteristics of wet turf but do not require watering to achieve them. It is an ambitious desire and one that looks difficult to achieve. What is the present status?
Back in 2018, FIH’s decision was viewed as just a hopeful wish, but anno 2022, the severity of certain weather phenomena or their occurrence in places that never expected to be on the receiving end, have made such pursuit an absolute necessity. The imbalance of our water consumption is particularly worrisome. According to the Sports Turf Research Institute, the world’s daily consumption of potable water is estimated to be around 10 billion litres. Yet, many communities around the world are forced to survive on only a few drops due to a lack of rainfall. Potable water has become so precious that any use other than answering the basic needs of plants, animals or humans, should be considered or re-evaluated carefully which is why FIH decided to pursue this quest.
Back in 2018, a single watering of one hockey field required 18,000 litres of water. These days, this demand has been dropped to approximately 6,000 litres while modern synthetic turf hockey fields also tend to hold water better. Nevertheless, elite surfaces for hockey rely heavily on water to deliver ball control, ball speed, surface grip and consistency, as well as helping to minimise skin burns when sliding or falling. The successful development of a non-watered turf by the synthetic turf industry will make infrastructural investments for hockey more attractive to the likes of the International Olympic Committee (IOC) or hosts of international tournaments that usually require multiple high-end surfaces for only a limited period. It will also lower or remove barriers to allow the sport to develop in countries where the watering of hockey turf is impossible or perceived as morally unacceptable.
Updating the standards
FIH Hockey Turf and Field Standards currently define the turf to be wet to ensure satisfactory performance for surfaces of the FIH Global category. These standards first have to be updated before FIH can go ahead with its plans. To be able to do so, FIH commissioned test institute Labosport and the English Loughborough University to, amongst other tasks, identify the key sports performance properties that distinguish between wet and dry surfaces. Labosport was also asked to develop new testing methods to measure the properties identified. “We identified four key game events where the characteristics of a water-based pitch are deemed to be important: the ball speed, oblique ball bounce, stick-surface friction and performing 3D skills like lifts, jinks, or pops,” explains Professor David James of Labosport UK. Together with Professor Paul Fleming of Loughborough University, he interviewed and studied elite players from various countries and gathered objective game relevant measurements of ball, stick and surface interactions. Surprisingly, shoe surface interaction wasn’t mentioned enough to also be considered. “The players we interacted with simply didn’t raise this as an issue.”
Translating the answers
The study has learnt that hockey players seem to prefer fast, wet surfaces that allow a quick, agile game and that allows skilled players to excel with their superior technique and specific 3D-skills. At the same time, the surface should not be abrasive so that injuries can be avoided. More constant conditions over time would be desirable. Next, a series of testing sessions with Loughborough University men’s first hockey team was conducted to obtain objective measurements of the identified game events. “Data gathered and input obtained enabled us to develop test methods for the four key game events,” Professor James continues.
The Labosport study was concluded earlier this year and a report has been handed to the FIH. In it, the testing institute proposes the introduction of a ball speed test that assesses the change in speed of a hockey ball due to its interaction with the playing surface during a high-speed event such as a long pass. For the test, an air cannon will launch a hockey ball horizontally at 15 m/s. Two pairs of infrared timing gates will measure the ball speed at two locations.
Labosport also proposes to use an air cannon to launch a ball onto a hockey surface with a speed of 14 m/s and at an angle of 43 degrees. A high-speed camera will capture the impact event while videogrammetry techniques track the ball trajectory before and after the impact. The average speed and angle of each trajectory will be calculated by means of Gauss’s elimination method to determine the oblique ball bounce of the surface.
To establish how the playing surface deforms when players perform a 3D skill, Labosport has proposed to use a test bench to apply load to a sample of the top-layer consisting of a carpet and shockpad, and measure the deformation. For measuring the friction between a hockey stick and the surface, it has proposed to use a sledge to pull three representative hockey stick profiles over the surface at a regulated speed. A sensitive load cell will be used to measure the frictional forces that are acting on the hockey sledge.
The report has now been distributed by FIH to other FIH accredited test institutes and to the synthetic turf industry. “This is to validate the proposals and to allow the reproducibility and repeatability of the new test methods to be determined. Only then can they be incorporated into the next edition of the FIH Hockey Turf and Field Standards,” FIH Facilities Manager, Alastair Cox told an audience earlier this year.
It is now primarily up to the yarn producers and synthetic turf manufacturers to take all this knowledge to the next level and develop synthetic turf surfaces or systems that have the playing characteristics of wet turf but do not require watering to achieve them. If rumours are anything to go by, the R&D Departments of the various companies will certainly be put to the test. “We are certainly facing a challenge,” admits Chris Vandenborre of Lano Sports. “Frankly, at Lano we already looked into the performance of non-watered turf systems for hockey in view of FIH Global performance back in 2017 and were able to develop systems that meet all the current FIH Global field test criteria. Just to be clear, these do not include any skin/surface friction/abrasion criterium, as this is only part of the official FIH laboratory test procedure. This development also allows for alternative, dry FIH National use of these wet-tested FIH Global systems.”
Meanwhile, FIH has initiated their new development program to investigate and map the differences between wet and dry surfaces, as perceived by the players particularly, considering player-surface, ball-surface as well as stick-surface interaction in an integrated approach. “It had actually become clear that the current FIH surface performance requirements are not providing a complete picture there.”
Fibres for synthetic turf hockey carpets should not contribute to skidding in either a wet or a dry condition. This can only be achieved by carefully selecting the type of polymer as well as the shape and stiffness of the yarn. “Over the years, our polyethylene, texturized monofilament yarns for hockey have demonstrated distinct improvements towards skin abrasion,” Chris Vandenborre continues. “Detailed tweaks in chemical composition, shape and dimension of the yarn, have allowed for this to happen. Realistically, within the polyethylene family further progress will remain a gradual and step-by-step process.” Another aspect of playing in dry conditions is an increased need for wear resistant material. “Although fibrillated fibres are generally regarded as less skin abrasive than monofilament, their lower resistance to wear and less resilient character make them less fit for purpose. While the tufting companies are keen on complying with the FIH requirements, they certainly will also have to satisfy the demand by their customers which is to deliver a surface that will perform and last for many years,” Vandenborre adds.
Why not reconsider nylon, the material used for the first synthetic turf surfaces ever built? Like Chris Vandenborre, Martien Damen of Condor Grass doesn’t expect a revival of nylon yarns for hockey surfaces in case other raw materials will be considered. “Nylon can absorb up to maximum 10% of its weight in moist but a nylon surface in dry conditions is significantly more abrasive than the polyethylene yarns we currently use,” he says. Back in the days, Condor Grass Sport produced nylon hockey surfaces before it switched to polyethylene yarns to produce these surfaces. “Nylon quality also tends to deteriorate much quicker when the surface is not wetted regularly,” he explains.
Playing with sand?
Both Lano Sports and Condor Grass have hockey products that require only 1 litre of water per square meter to satisfy the FIH Global conditions. “Although this reduces the demand for water from 18,000 litres to only 6,000 litres per watering per field, this is still more than the zero-mark FIH wants to set,” Vandenborre points out.
Martien Damen believes that a solution can be found when the hockey fraternity will value sand-filled and sand-dressed systems again. “If water is no longer allowed to deliver the characteristics, sand will be the next thing that springs to mind. You will need something to support the verticality of the pile,” he explains. “One thing we can consider is reviewing the shape and dimensions of the sand particles we use.” Damen points out that sand-dressed systems are as durable as water-based pitches. “Sand-dressed fields wear more evenly, as the fibre is always supported.”
However, Alastair Cox remarks that the use of infills that are abrasive to players and yarns is not something the FIH is keen to endorse. “We hope that its current requirement that Global category surfaces should be non-filled will remain,” he says.
Ideally, the new surface will first be tested no later than the FIH Hockey5s World Cup in 2024, before it is introduced to the World Cup tournaments as well as Youth Olympic Games in 2026. The final goal is to roll it out at the 2028 Summer Olympics in Los Angeles. With Labosport having established how a wet turf should perform as well as testing procedures that can be used to establish if the turf complies, the game is now on for the tufting companies to develop a new, hockey system for the elite level that doesn’t require water at all.