Pitch perfect

Source: scenta
Artificial grass
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In a country with weather as unpredictable as Britain’s, making sure football pitches and other sports venues’ playing fields are kept in a good condition is really important. Nothing should get in the way of the spectacle provided by a good match, especially not puddles, patchy grass and frozen surfaces.

The UK’s most popular sports are all played outdoors, making them particularly vulnerable to the elements. To counteract their effects, technology has come to the rescue in the past 25 years. Developments such as under soil heating and artificial grass pitches have achieved varied degrees of success, but today most grounds employ at least one of these improvements.

The grass is greener

Although artificial turf was invented in the 1960s, almost 20 years went by before any English clubs decided to replace their pitches. The frontrunners were London’s Queens Park Rangers, who dug up their grass pitch and installed an artificial one in 1981. Luton Town, Oldham Athletic and Preston soon followed QPR’s lead.

The advantages of artificial grass for a club that is strapped for cash are obvious: good grass pitches are very expensive to maintain, particularly as stadiums get bigger and darker. Busy grounds may require the grass to be re-laid up to four times a year, with maintenance costs reaching as much as £200,000 per season.

Artificial grass for football pitch

However, the artificial turf of the 1980s wasn’t up to scratch, and soon the four clubs that had adopted the development became a national joke: the ball bounced around in a weird way because of the harder surface, the players had their movements restricted and couldn’t wear normal boots, and anyone who fell over risked carpet burns because of the nylon fibres.

More dangerously, the harder playing field increased the athletes’ risk of injury, the most common being turf toe – an injury to the joint and connective tissue between the foot and one of the toes that can sideline a player for months. This made players wary of tackles, and the game lost a bit of its edge. Unsurprisingly, fans protested that the games were awful to watch and, one by one, the clubs went back to natural grass. 

Engineering plays its part

In the following decade, artificial pitches were banned by FIFA, UEFA and several domestic associations worldwide. Turf engineers then realised they can’t simply design a surface that looks like real grass, but that they have to mimic the exact properties of natural turf so that any product they create will have the same attributes. To this end, biomechanics researchers performed tests on natural turf and studied how footballers move around the pitch, in addition to the behaviour of the ball on grass.

The City of Manchester stadium

The results of years of research and experimentation are two systems that artificial turf manufacturers claim to faithfully reproduce the attributes of real grass. The most common type uses polyethylene fibres about five centimetres long, which are lubricated with silicone and sewn into a rubberised plastic mat. The base is then filled with a 4-centimetre layer of sand and rubber granules – this will keep the ‘grass’ blades upright and provide the required levels of shock absorbency and deformability. This is the technology used by most of the turf manufacturers approved by FIFA.

The other kind of artificial turf has a base of expanded polypropylene, a material originally created as a shock absorber for the automotive industry. The grass is made of the same lubricated polyethylene fibres as the first type, but they are shorter and more densely packed, and are also combined with short, curly, spring-like fibres that keep the blades upright. An 8-millimetre filling of rubber granules completes the system.

Hybrid system

According to UEFA’s injury statistics, the new artificial pitches are actually safer than natural ones, with 3.2 muscular and ligament injuries per 1,000 playing hours compared with 7.6 on grass. However, many players still have reservations about the non-natural surfaces.

In order to get the best of both worlds, some of Europe’s top clubs have resorted instead to a ‘middle of the road’ alternative: Desso’s DD GrassMaster. Created in Holland, this system uses 100 per cent natural grass, reinforced by 20 million artificial grass fibres. The artificial blades reinforce the natural ones, increasing the durability of the pitch: approximately 250 match-hours per year are played on a normal soccer field, while on a DD GrassMaster pitch the total may exceed 900 hours, taking into account match and training use.

Dessos DD GrassMaster

The GrassMaster has already been adopted by clubs such Liverpool, Reading, Tottenham Hotspur and West Ham United in the UK, and most recently at Arsenal’s new Emirates Stadium. Other major European outfits, such as Feyenoord in the Netherlands and Real Madrid in Spain also use this type of surface.

Heating and drainage

Almost as important as the playing surface itself is keeping it dry and in top condition – rain and snow could otherwise require a match to be postponed, resulting in enormous expense to the club hosting the game. To this effect, most football grounds in Britain employ under soil heating, a method witch keeps the pitch from building up puddles or frost from the inside. While it is not an official requirement, it is financially sound to have it installed.

There have been occasions where under soil heating's effectiveness has been questioned, however. The most notable and recent incident happened in 27 December 2005, when three grounds in the FA Premier League, supposedly equipped with the system, failed to stop their pitches being covered in thick snow, which led to the matches being postponed. The competition organisers subsequently investigated the reasons why the pitches at the Reebok Stadium, Ewood Park, and St. James' Park (Bolton Wanderers, Blackburn Rovers and Newcastle United respectively) were not able to repel the snow.

The Emirates Stadiums pitch uses FAVVS

One of the most advanced drainage structures available for football fields is the Forced Air Ventilation and Vacuum System (FAVVS). This ducted vacuum and air pressure system can carry out two operations. First, fresh, cool air and oxygen for natural growth will be supplied to the crucial area near the roots of the grass plants. A vacuum phase means that the system is able to drain any surplus water after heavy rainfall. Combined with a pop-up, automatic irrigation system and the under soil heating, a good drainage system ensures the pitch will be kept in optimum conditions for play.

The show must go on, and in football, technology makes sure this will (almost) always be the case.

You’ve read it. Now review it.

Source: scenta
Date Published: September 28, 2006
 
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