This article is about a seminar topic artificial turfs.
Artificial turf is a surface manufactured from synthetic fibres made to look like natural grass. It is most often used in arenas for sports that were originally or are normally played on grass. The main reason is maintenance — artificial turf resists heavy use, such as in sports, better, and requires no irrigation or trimming. Domed, covered, and partially covered stadiums may require artificial turf because of the difficulty of getting grass enough sunlight to stay healthy.
A common misconception is that the new synthetic grass is similar to the household carpet. In fact this intricate system involves properly constructing a porous sub base, and using turf with holes in the back, then the product is filled with sand/rubber granule mix which we call infill.
Artificial turf, also known as synthetic turf, has found a prominent place in sports today. Manufactured from synthetic materials, this man-made surface looks like natural grass. With the international sports associations and governing bodies approving the use of artificial surfaces, sports like football and hockey, which were originally played on natural grass, have moved to these artificial sports pitches. So, next time, you find players playing on an artificial hockey pitch, do not be surprised.
Artificial turf has been manufactured since the early 1960s, and was originally produced by Chemstrand Company (later renamed Monsanto Textiles Company). It is produced using manufacturing processes similar to those used in the carpet industry. Since the 1960s, the product has been improved through new designs and better materials. The newest synthetic turf products have been chemically treated to be resistant to ultraviolet rays, and the materials have been improved to be more wear-resistant, less abrasive, and, for some applications, more similar to natural grass.
2. NEED FOR ARTIFICIAL TURFS
( Ref: Natural Grass and Artificial Turf :Separating Myths and Fact)
The playing surfaces where artificial turf is installed tend to remain consistent. They require no sunlight or constant watering. It needs no seeding or fertilizers or pesticides and you do not need to mow it down. Such low-maintenance has made is an extremely viable option.
Initially, it was mostly clubs and stadiums that were investing in artificial turfs, but increasingly individuals with a large backyards have also started to choose synthetic turfs for the sake of convenience.
Also, in environments as big cities possess, where soil is scarce and pollution rampant, natural grass finds it hard to grow. If it does grow, it might be uneven, patchy and not as attractive as we would like it to be.
The quality of the raw materials is crucial to the performance of turf systems. The raw materials used in the construction of artificial turf are as follows:
3.1 THE GRASS FIBER
The fibers that make up the blades of "grass" are made of nylon or polypropylene and can be manufactured in different ways. The nylon blades can be produced in thin sheets that are cut into strips or extruded through molds to produce fibers with a round or oval cross-section. The extruded product results in blades that feel and act more like a biological grass. The blades may have different length depending upon the type of field. i.e. blades used for football will be different from that of in hockey and tennis and so on. The detail of the type of games, fiber height, gauge length. is given below:
TYPE OF GAME FIBER HEIGHT GAUGE LENGTH
FOOTBALL 40MM-60MM 5/8 INCHES
HOCKEY 10MM-25MM 5/32-3/16INCHES
3.2 BACKING MATERIAL
Almost anything used as a carpet backing has been used for the backing material, from jute to plastic to polyester. High quality artificial turf uses polyester tire cord for the backing.
Cushioning systems are made from rubber compounds or from polyester foam. Rubber tires are sometimes used in the composition of the rubber base, and some of the materials used in backing can come from plastic or rubber recycling programs.
The infill holds and absorbs water which eventually drains through the holes to the sub base system. Some water will run off the top under heavy rains just the same as natural grass. Correctly installed synthetic grass will drain quicker than natural grass.
It is used in the drainage system. Its property of draining the water through the top surface without any infiltration towards the bottom layers is utilised for the drainage process.
Coarse aggregates or pebbles passing through 3/4” and retaining at 3/8” are used to fill the sub base layer.
Fine aggregates or sand is used to fill the top layer. They are also used in between the sub base layer in order to provide a backing for the drainage system.
3.6 OTHER MATERIALS
The thread used to sew the pads together and also the top fabric panels has to meet the same criteria of strength, color retention, and durability as the rest of the system. Care and experience must also be applied to the selection of the adhesives used to bond all the components together.
4. TYPES OF ARTIFICIAL TURFS
(Ref: Artificial turfs- myths and facts)
The artificial turfs used in play grounds are of three types. The type of turf that is to be installed depends upon the game that is going to be played in the ground. The type of raw materials used and the installation procedure depends upon it. The description of commonly installed three types is given below.
Unfilled Often called "water-based", the pile is unfilled. The fields require wetting, hence the name "water-based", often via prolonged showering with field-side water cannon prior to their use and occasionally during half-time intervals depending on the prevailing atmospherics. They are favoured by most sports since they offer more protection for players by minimising the abrasive effect created by the sand. These fields form the majority of the elite level field hockey fields in use today.
Sand-dressed The pile of the carpet is filled to within 5–8 cm of the tips of the fibre with fine sand. The sand cannot be seen. It can be confused with unfilled fields.
filled The pile of the carpet is filled almost to the top with sand. The sand makes the field rough and harder. In comparison to water-based fields or minimal sand-dressed fields, ball speed across the surface is often noticeably slower.
SAND FILLED TURF
UN FILLED TURF
( Ref: Artificial turfs)
1. Mark off the area that you will install with an outdoor spray can marker. onsider the dimensions of your Turf to try to get as few seams as possible with your layout.
2. Remove sod, you will need to remove approximately 120cm to 150cm of soil. Ideally, the sub base will be pitched slightly towards the best direction to allow for water drainage to run-off.
3. The base of the installation, which is either concrete or compacted soil, must be leveled by a bulldozer and then smoothed by a steam roller. Uneven surfaces will still be evident once the turf is supplied. It is usually laid at a depth of 20cm -30cm from base.
The sub-base is filled with corse aggregates or pebbles at a depth of 25-75 cm. It is very important to ensure the sub-base is completely dry before laying any crushed rock to reduce settling and ensure proper compaction for the surface. Once you confirm that the sub-base is dry, add a top layer of crusher dust or a 2cm-5cm crushed rock (these types are best so you don't feel any protruding rocks when you walk on your Turf). The purpose is to firm and level your base, 25cm –50cm of base is usually enough, although in some areas of the country where soil is especially unstable you may need up to 75cm of base material. Please note if more than 50cm of base material is used, you will also need to increase the amount of soil removal.
5. For outdoor applications, intricate drainage systems must be installed, since the underlying surface can absorb little, if any, rainwater.
6. Spread and then compact the sub base material twice. Use the vibrating compactor again.
7. Finishing Sand layer (not always required if crushed rock is adequately smooth).
Spread a fine layer of sand (approx. 2-5cm using just an ordinary seed drop spreader) on the surface to make it more level. You may also use a water-filled sod roller for an even more level surface.
8. Check surface for depressions.
Any depression areas 1cm-2cm or deeper should be filled-in and re-levelled. Although the turf also drains vertically through the drainage holes that are manufactured in the turf, it is still advisable to give the sub-base a slight slope, to avoid any pools of water.
9. Roll out Turf.
Position the turf where it goes, be accurate (so you don't cut off turf you actually need). Try to avoid dragging the turf as this may dislodge some crushed rock or sand.
10. Cut the turf.
Cut off excess material so it's easier to work with. Always use a sharp blade in your utility knife! Make sure turf is still positioned where it goes. Now, trim turf more exactly with straight lines. For optimal performance and beauty, make sure the turf is installed exactly over the prepared based.
Where two pieces of turf come together you will need to make a seam. It's really not that difficult as the Turf is fairly high and seams are generally less noticeable than that of thin pile carpet. The seams are simply glued together with outdoor turf adhesive and 300mm wide seaming tape.
At the joining seam, a 300mm wide piece of seaming tape should be cut to the length of the seam. The turf is to be laid seam to seam the way that it should look to ensure it fits tightly together before it is glued.
The pattern of turf stitching on the under side must run in the same direction before the two pieces are adhered. Both sides of the turf at the seam must be pulled back in order to install the seam tape. Before adhering both pieces ensure that both edges have been properly trimmed, straight, and will match up perfectly. Lay the seam tape down on the base directly between the two pieces of turf that are to be joined. Apply gluing compound to the entire piece of seam tape with a notched trowel. Place one side of the turf in the middle of the tape (approximately 150mm) to the centre of the tape. Lay the other side of the turf over the middle of the seam tape to match up exactly to the turf that has just been adhered to the tape. Mesh the fibres together with fingers or brush. Allow 24 hours for glue to properly dry. The following procedures can be administered during the drying time, but turf may shift and require repositioning.
12. Infill Preparation.
Once glue has dried, trim off turf so your lawn fits as desired. Next, it is a good idea to nail the perimeter every 500mm-800mm with nails (80-120mm length). In order to prepare to infill the turf, rake or power broom the turf in the opposite direction that the turf is laying on the roll. This will allow the infill material to infiltrate the turf rapidly and prevent turf blades from getting trapped in the in fill. The infill process will now commence using a standard seed drop spreader with either sand or crumb rubber as an infill. The infill helps to weigh the turf down, and stabilize the fibres so as to help avoid "matting". Most use sand infill as it is the least expensive compared to rubber infill. Of course rubber is more shock absorbent than sand, so choose what you can afford and prefer, although it is advisable to have at least the top half in rubber infill. You want to calculate the amount of infill in advance, as you will want to leave around 15mm of grass blade exposed. As a general rule of thumb, approximately .75 of a kilogram of sand equals around 10mm of in fill height. For a crumb rubber infill, use approximately 5 kilograms of rubber per sq metre for every 10mm of in fill height. Spread the infill in several passes. As you spread the infill you should make one entire pass on the surface then sweep it down into the fibres, repeating the process until all of your infill has been spread.
13. Optional Edging.
Depending on your yard, you may want to install some type of edging material around your new lawn. Examples are natural stone, brick, rock borders, metal edging, plastic edging and timber edging are popular.
6. DRAINAGE SYSTEM
Synthetic turf is an evolving industry and is frequently used as an alternative to natural grass. Drainage is a critical design element for any synthetic field. Lack of proper drainage creates surface run-off issues and reduces playing time.
Stone base drainage designs are expensive and have performance limitations. Typical stone drains require from 6-8 inches of aggregate, extensive site excavation and high transportation cost to haul stone to the site and to remove excavated soil from the site. Stone bases are hard, rough surface that provide poor footing, resulting in potential injuries to players.
The infill holds and absorbs water which eventually drains through the holes to the sub base system. Some water will run off the top under heavy rains just the same as natural grass. Correctly installed synthetic grass will drain quicker than natural grass.
A drainage system is provided for a synthetic grass turf assembly having a flexible and water permeable sheet backing for installation on a supporting soil substrate to provide a game playing surface. The draining system of the present invention prevents water from accumulating on the turf surface, which could cause the top-dressing layer to “float” and be moved by inundation.
As mentioned above in the installation process, the drainage system is fixed on the sub base layer. It is installed at a depth of 50-75 cm from the surface of turf. The sub base layer is filled in two phases. The lower portion of sub base is filled in inclination with the pebbles. In order to make the pipe in position a sand layer is provided on the top. At middle above the sand layer a long pipe is installed. The diameter of the pipe varies from 10-20 cm and it has aslope of 1/500 to 1/750 along the length of the ground.
Above the sand layer separator geo membrane and above the pipe filter-geo membrane is installed. The geo membrane is laid at a slope of in 1/20. The remaining sub base is filled with coarse aggregate or pebbles and the base corse is filled with sand and above the prepared ground the turf is fixed.
The water from the grass fibre passes through the infill and then through the base corse to the sub base collected through the aspirator geo membrane to the filter geo membrane, then it flows out through the pipe. The pipe leads out of the stadium.
In addition to this the drainage facility provided on the periphery is also present at the ground. Thus any chance of water logging conditions is avoided
(Ref: Lawn maintenance)
With our synthetic turfs you will never have to mow, irrigate or fertilise your surface ever again. However, you will have times when you will want to clean the artificial turf fibres or need to clear off fallen leaves in the fall. There are simple procedures to be followed in order to maintain your artificial turf in an optimal condition.
The recommend weekly servicing includes: brushing and clearing the turf of any dirt – scraps, garbage or leaves. Once a year, a special servicing team should check the condition of the surface and, if required, conduct all the works necessary for increasing its quality and life-span.
Routine maintenance generally includes keeping the surface clean of debris, especially that which may decay into the infill, and occasionally sweeping the fibres up to revitalize the appearance of the lawn.
Rain is your best cleanser. Rainfall gently cleans the turf fibres of dust, pollen and airborne pollutants in a way that is difficult to duplicate in any other fashion. In areas where rainfall is scarce--or during prolonged periods of drought--an occasional water flush is beneficial to soak and thus cleanse the turf system ( only if water restrictions allow ). This procedure is recommended for all turf systems.
Keeping a beautiful green playing field for sports like soccer, football, and baseball is important and requires lots of work. Watering or irrigating the surface is done for it. It is done by two ways;
1) Water Reel system and
2) Underground sprinkler system.
7.1WATER REEL SYSTEM
When you are watering a synthetic turf Water-Reel is the perfect tool for the job. With many models, sizes and lengths to choose from, you can pick the best reel for your application, which, in some cases, will allow you to irrigate the whole field in one unattended pass.
• More affordable than in ground irrigation systems, which can cost up to four times as much
• Little or no risk of damage to the synthetic turf from broken in ground lines
• Improves recovery of damaged turf in high traffic areas
• Improves playing conditions and appearance of fields
• Irrigates sports ¬fields in a single pass
One of the few improvement projects that is done is installing a sprinkler or irrigation system for your yard. At the most basic level, a sprinkler system contains a few main components. The first is the controller. This is an electronic, computerized unit that normally hangs on the wall of your garage. It is the "brains" behind the sprinkler system, with a timer that tells your system which set of sprinkler heads should turn on when, and for how long. The controller is connected to a set of valves that regulate the flow of water into a specific "zone" in your sprinkler system. The valves act like faucets that turn off and on when told to by the controller. The valves are tied directly into your water system and are normally found in buried plastic boxes with removable lids for access. The valves then feed water into the rest of the sprinkler system, which is composed of plastic PVC pipes that lead to the actual sprinkler heads. The pipes are all buried approx. 12 inches underground. The sprinkler heads are set normally at about ground level when not in use, and then they pop-up when the water pressure fills the pipes below them.
The cost of an automatic sprinkler system can vary region to region, but it depends mainly on 2 factors - the size of your lawn or yard to be irrigated (ie, how much pipe needs to be laid, how many physical sprinkler heads are needed) and the components you choose to build your system. For a 2500 square foot lawn, you could expect a figure of around $2000-$2500 for an underground sprinkler system.
7.3 ADDITIONAL TIPS IN MAINTAINANCE
(Ref: Lawn maintenance)
Do not use any tools that may damage the surface and do not use solvents like acetone or cleaning materials containing alcohol.
Pay special attention to the most heavily used areas. Keep extra sand or rubber infill as after a minor settling period, you may wish to fill-in any minor “low spots”. If you encounter a low spot, take a bucket of infill, locate the spot and apply several thin layers of infill to the area and brush into the fibres with a stiff street broom or small hand held fibre scrub brush (such as is used to hand scrub floors). Brush in several directions.
Every loose foreign object, no matter how small, can damage your Turf by abrading the fibres and/or contaminating the fill. Remove all leaves, twigs, paper and any other waste items on a regular basis.
To keep the infill from compacting and to limit the fibres from “matting down”, brush your Turf on a semi regular basis. Always brush the Turf in opposite directions, as continuous brushing in one single direction will produce unacceptable pile lean.
In case of seams opening, it should be repaired soon as quickly as possible to prevent the situation from deteriorating.
Snow removal: Generally snow and ice should be left to melt and drain off the system without assistance. At times, however, it may be desirable to remove snow or ice. If you elect to plough the snow, leave a layer of snow of 1 inch as to protect your Turf from mechanical damage. The final layer of snow can be removed by brushing.
Do not park vehicles on the Turf. You also do not want direct, hot engine exhaust to be discharged onto the Turf for extended periods.
Prevent lubricating oil, grease, transmission fluids, etc., from dripping or spilling on your Turf surface during sweepings. Such spills can discolour the Turf. Battery acid and other such fluids should not be allowed on the Turf. Never change or add fluids to maintenance equipment while on the Turf surface.
The Turf fibres are highly stain resistant because most stains are moisture borne and the polyolefin-based fibres tend not to absorb moisture. Hence, most stains on Turf are not true stains but rather residues of foreign matter that must be promptly and thoroughly removed. Most stains can be removed with water or soap and water. The first rule is promptness. It is much easier to clean up a fresh spill before it has time to dry and harden. Remove any solid or putty-like deposit promptly using a dull knife or spatula-like tool.
Neither long-term static load of more than 2 psi, nor any transient or dynamic load of more than 35 psi should be allowed on the surface. The loading of a pneumatic-tired vehicle is approximately equal to the air pressure in its tires. Hence, it is good practice to eliminate any unnecessary long-term parking and loading and to keep the necessary ones as low and brief as possible.
Enforce a smoke-free environment, if possible, and discourage the use of fireworks, fires and chewing gum.
8. CASE STUDY
8.1 SALT LAKE STADIUM, KOLKATA, WEST BENGAL
It is also known as Yuba Bharati Krirangan.Salt Lake stadium is situated in Kolkatta and it was built in 1984 and holds 120,000 people. It is the second largest stadium in the world (first in Asia) and the stadium covers an area of 76.40 acres. The main football arena measures 105m x 70m. It is the home ground for Mohanbagan F C and East Bengal F C At present it is the only football stadium in India with artificial turf .
Last year the Government of West Bengal spend around Rs. 5 Crores (50 Million) on installing an artificial turf pitch at the Saltlake Stadium.The turf installation was for 90,000 square feet. It was undertaken by Fieldturf Tarkett India from Hydrabad who also laid the artificial turf at Luzhniki Olympic Stadium in Moscow, the pitch was accorded one-star status for a four-year period till March 23, 2014.
8.2 OTHER ARTIFICIAL TURF INSTALLED STADIUMS
North Harbour Hockey Stadium, NEWZEALAND –TIGER TURFS
Workington Cricket Club (Synthetic Turf)
Major Dhyan Chand National Stadium, Delhi
G. M. C. Balayogi Athletic Stadium, Hyderabad
WORLD CUP STADIUMS
Among the world cup stadiums in South Africa , two were installed with artificial turfs. They are:
Soccer City Stadium, Johannesburg
Free State Stadium, Bloemfontein
Vashi school sets up India's first multi-sport artificial turf ground in, NAVI MUMBAI
It was done by Green Fields BV, the Dutch manufacturer of the artificial turf. The 103m by 65m field which costs Rs 3 cr with floodlights.
9. ADVANTAGES AND DISADVANTAGES
( Ref :Natural Grass and Artificial Turf :Separating Myths and Fact)
• Artificial turf can be a better solution when the environment is particularly hostile to natural grass. An arid environment or one where there is little natural light are examples.
• Artificial turf can withstand significantly more use than natural grass and can therefore be used much more frequently. This allows sports ground owners to generate more income from their facilities.
• Ideal for holiday homes when maintenance of lawns is not practical. It is also a solution for elderly homeowners who find the upkeep of lawns too much hard work.
• Suitable for roof gardens and swimming pool surrounds.
• Some artificial turf systems allow for the integration of fibre-optic fibres into the turf. This would allow for lighting or advertisements to be directly embedded in a playing surface, or runway lighting to be embedded in artificial landing surfaces for aircraft.
Some areas may not enjoy a climate conducive for growing natural turf on a year-round basis because of either severe summers or severe winters. Synthetic turf provides a magnificent alternative.
• Covered and Shadey areas.
Limit natural sunlight making cultivation of natural turf more difficult.
• Reduced Maintenance.
Does not require seasonal fertilization, mowing, trimming and aeration as natural turf does.
Although upfront costs of synthetic turf are greater than natural turf over its life cycle synthetic turf is cost-effective when one factors in reduced maintenance (including chemicals) and reduced usage of water.
• Abrasion injuries caused by artificial turf have been linked to a higher incidence of MRSA infections
• Some artificial turf requires infill such as silicon sand and/or granulated rubber made from recycled car tires. This material may carry heavy metals which can leach into the water table.
• Periodic disinfection is required as pathogens are not broken down by natural processes in the same manner as natural turf. Despite this, recent studies suggest certain microbial life is less active.
• Friction between skin and artificial turf causes abrasions and/or burns to a much greater extent than natural grass. This is an issue for some sports: for example, football in which sliding manoeuvres are common and clothing does not fully cover the limbs. However, with some third-generation artificial grasses, this is almost completely eliminated by the use of polyethylene yarn.
• Artificial turf tends to be much hotter than natural grass when exposed to the sun.
(Ref: Artificial turfs)
The engineering and design of both artificial and biological turf systems are constantly improving. As new stadiums are built, the owners and architects strive to give a more old-fashioned feel to the structures, which usually means no dome or a dome that allows the use of biological turf.
Recent installations of artificial turf have included new advancements that serve both economic and environmental needs. Large holding tanks are built beneath outdoor installations. The water that runs off the surface is held in the tanks, and used later for watering practice fields or nearby lawns.
Another recent development has been a hybrid of filled turf and biological grass. Once artificial turf is installed, it is filled not with rubber or sand, but with soil. Grass seed is then planted in the soil, nurtured and grown to a height above that of the artificial turf. The resulting combination combines the feel, look, and comfort of biological turf with the resilience and resistance to tearing and divots of artificial turf. Of course, it also requires all the maintenance of both systems, and it is not suitable for most indoor applications.
The use of artificial grass in gardens is on the rise, especially in the UK and the United States. California’s largest water district has been issuing rebates to residents who have installed synthetic lawns.
Other water conservation organisations have also realised how artificial grass can help to conserve water. Supporters of artificial grass will argue that a synthetic lawn can save thousands of gallons of water, herbicides and fertilizers. Also, by eliminating lawn mowers, there is less creation of pollution caused by the use of fuel.
Different companies create different types of fake grass. Technical advancements ensure that there is a large variety and a higher quality of artificial lawns. These days, synthetic grass looks very realistic and you won’t find bumps or uneven surfaces.
Although installing synthetic grass is expensive, the low level of maintenance that is required can prove to make it less costly than maintaining a natural garden. Fake turfs can withstand intense heat, rain, snow and ice and generally last for about 10 years or so.
In the early 21st century, new artificial playing surfaces using sand and/or rubber infill were developed. These "next generation" or "third generation" artificial grass surfaces are generally regarded as being about as safe to play on as a typical natural grass surface — perhaps even safer in cold conditions.
Many clubs have installed the new synthetic grass surfaces, most commonly as part of an all-weather training capability. Other clubs which have maintained natural grass surfaces are now re-considering artificial grass. With football clubs in Europe looking to reduce both the maintenance costs and the number of winter matches that are cancelled due to the playing surface being frozen, the issue has also been re-visited by that sport's governing bodies.
The use of artificial grass in gardens is on the rise, especially in the UK and the United States .Artificial turf can withstand significantly more use than natural grass and can therefore be used much more frequently. Water conservation organizations have also realised how artificial grass can help to conserve water. Technical advancements ensure that there is a large variety and a higher quality of artificial lawns. These days, synthetic grass looks very realistic and you won’t find bumps or uneven surfaces. Although installing synthetic grass is expensive, the low level of maintenance that is required can prove to make it less costly than maintaining a natural garden. Fake turfs can withstand intense heat, rain, snow and ice. Artificial turf grass can also solve problems of cleanliness. Artificial grass still needs some level of maintenance. .Protecting the field is about protecting the environment, your investment and most importantly, your players. It is not about protecting innovation, but more importantly, innovating protection.