TYR008 Playtop Case Study Final1.5c7f48af

8/6/2019 TYR008 Playtop Case Study Final1.5c7f48af

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www.wrap.org.uk Waste Tyres Case Study: TYR0008 Playtop play surface 1

Playtop Safer Surfacing : Tyre crumb in play su rfaces

Product: Play surface

Material: Waste tyre crumb

Application: Bound

Project Type: Ground cover

Location: South Yorkshire and London

Date: 2005

Specification: Rubber crumb based playing surface. Playtop surfacesare made from tyre crumb mixed with polyurethanebinders and used for playground areas. Two examples of its use are in the London Borough of Hammersmith andFulham and the Magna Science Centre in Rotherham.The surfaces are manufactured by Playtop Ltd, asubsidiary of Charles Lawrence Group plc of Newark.


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Overview

Charles Lawrence Group plc, through their subsidiary Playtop Ltd, manufacture Playtop, arubber crumb based playing surface. The crumb is manufactured from granulate that isprimarily derived from waste commercial vehicle (CV) tyres. Approximately 30 tyres produceone tonne of granulate, equivalent to about 61% of the total weight of the tyres. Theremaining 39% is also recycled, rendering the tyres fully recycled.

The playing surfaces are available as either a black finish (Figure 1) or in vibrant colours(Figure 2).

Source: Playtop Ltd

Fig.1: Playtop on the Maystar Estate

Source: Playtop Ltd

Fig.2: The vibrant colours used at Magna Science Centre


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Technical details

Description Units Annual laid playground area 80,000m 2

Annual CV tyre consumption 80,000 unitsCV Tyres/tonne granulate ~30Tyres/m 3 Playtop ~14

Yield of suitable granulate/CV tyre 61%Total recycled yield/CV tyre 99+%

Average granulate density 430-490Kg/m 3Granulate size range 1-20mm

Background

Playtop playing surfaces were first used in 1977 on a housing estate near Loughborough,Leicestershire. At that time, the product consisted of 12mm thickness of porous rubber laidon asphalt or concrete, with a sprayed top coat. However, since then the product hasdeveloped into a very sophisticated material suitable for the most arduous of playconditions. The product range has been developed to provide surfaces for playgrounds andother play areas such as tennis courts, athletics tracks and other sports arenas, but not allend-uses utilise the recycled rubber products. In 2005 the company installed approximately80,000m 2 of their playing surfaces worldwide. This is equivalent to in excess of 5,600m 3, orthe consumption of 2,670 tonnes of tyre-derived rubber granulate.

The product is a continuous, porous material made from twin layers of rubber granules(tyre-crumb base topped with EPDM) and polyurethane binders. It is mixed and laid on-siteas a wet-pour product. It is extremely strong and durable, retaining its life-savingdeformation properties for many years of hard use, making it ideally suited for use onchildrens playgrounds and other areas where slips, trips and falls may occur and

satisfactory safety protection is required.

The playing surfaces are made in part from granulated rubber obtained from recycledcommercial vehicle (CV) tyres and it is estimated that one tonne of granulate requiresapproximately 30 commercial vehicle tyres to produce it. This is equivalent to theconsumption of about 14 tyres per cubic metre of product. However, the manufacturingprocess for tyre granulate can be considered to be virtually 100% recycling, as the textilesand steel present in the tyre are also recycled.

The rubber crumb is obtained directly from Charles Lawrence International (CLI), anothersubsidiary of Charles Lawrence Group plc. The average commercial vehicle tyre typically

yields about 35% rubber contaminated steel, 3% textile fibres and 62% rubber crumb. 1%


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of the crumbed rubber is lost as fibrous waste when fine crumbing is carried out. Thisresults in the average tyre yielding 61% by weight of rubber crumb.

The granulating plant for CLI is located in Newark, Nottinghamshire, and they receive tyresfrom a variety of collectors who have sorted the feedstock for their recycling suitability. Anytyres not suitable for re-use are sent for shredding and granulating.

CLI granulate about 400,000 truck tyres annually. Of this, about 80,000 tyres are destinedfor sister company Playtop Ltd and the rest are consumed by other companies in the sportand play sectors with small amounts used in alternative markets.

Specification, Quality Assurance and Design

The Playtop product comprises two layers of rubber. The base layer is coarse (20mmmesh) black granules obtained from recycled tyre rubber and the top layer is a coloured andmuch finer EPDM (Ethylene Propylene Diene Monomer) rubber particle. EPDM is a widelyused synthetic rubber. Both layers are bound together with polyurethane resin. In a recentdevelopment in partnership with Nikes corporate social responsibility programmes, theEPDM can be blended with recycled and granulated trainer soles.

Each project has its own specification, depending on the play area usage and design. Thetotal thickness of the rubberised playground surface used will depend on the Critical FallHeight specifications as required by BS EN 1177.

Two projects are considered in this case study. The first is a childrens playground on theMaystar Estate near Star Road, London W14, in the London Borough of Hammersmith andFulham. The second project uses a coloured surface and is at the Magna Science Centreproject in Rotherham, S60 1DS.

May star Estate, Ham mersm ith and FulhamThe Maystar Estate project was completed in July 2005 and installation took approximatelyone week. The substructure engineering was carried out by the main contractor on site, butthe actual installation of the playing surface was carried out by Playtop Ltd.

Figures 3 and 4 show the playground after completion.


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Source: Playtop Ltd

Fig. 3: Maystar Estate playg round

The total playground area is about 346m 2 and comprises three different thicknesses. Themajority of the play area (210m 2) required a total depth of surfacing of 40mm, as this had aCritical Fall Height (CFH) requirement of 1.3 metres. However, there are also other areasrequiring better CFH ratings: 61m 2 were laid to a depth of 60mm and a further 75 m 2 werelaid to 100mm. The 60mm depth offers CFH protection to 1.6 metres and 100mm offers itto 2.5 metres. Despite the top surface being coloured black, all the surfaces consist of anominal depth of 15mm EPDM granulate as the top, or wearing, layer. It is estimated thatabout 14.4m 3 of base layer recycled granulate was used in the Maystar Estate project.

Source: Playtop Ltd

Fig. 4: May star Estate playground climbing frames and slide

In all, the project consumed approximately 15 tonnes of rubber, of which 92% was eitherrecycled or post-industrial waste material. It is estimated that about 10 tonnes of materialwere obtained from commercial vehicle tyres and the remainder from post industrial and theNike Grind recycling programme. The post industrial EPDM rubber was blended with15-20% recycled and granulated trainer soles and used in the wearing course layer.


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Magn a Science Centre, Rotherh am, YorkshireThe play area at the Magna Science Centre was installed in May 2005, taking about twoweeks to complete. Playtop Ltd did not do the ground work, but laid the playing surface.

Figures 5 and 6 show different parts of the Magna Science Centre play area, and reflect thevivid colours available.

Source: Playtop LtdFig. 5: Magna Science Centre playground railw ay

In all, an area of about 550m 2 of Playtop Safer Surfacing was laid, requiring a total of

about 23 tonnes of rubber, of which approximately 70% was derived from recycled sources.Magna Science Centre reused about 18 tonnes of waste tyre rubber, equating to almost 500commercial vehicle units. Unlike the Maystar Estate playground, the top or wearing surface at the Magna Science Centre is multicoloured (Figure 6) and is therefore made fromvirgin EPDM.

Source: Playtop LtdFig. 6: Magn a Science Centre play area


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The m anufacture of Playtop surfaces

Tyre granulesTyres are sourced from major suppliers of used tyres such as new tyre manufacturers andtyre collectors. The tyres are ground in a HG42 heavy granulator (Figure 7) which is alsomanufactured by Charles Lawrence International.

Source: Charles Lawrence International Ltd

Fig. 7: HG42 Heavy Granulat or

The HG42 granulator is an electrically driven heavy duty granulator for the size reduction of rubber and a variety of similar end-of-life materials. The output particle size can beadjusted by means of interchangeable screens. The motor is driven from a 415V, 3-phasepower supply and is rated at 75kW. The drive is by multiple V-belts. The machine is freestanding, weighs approximately five tonnes and is 2.2 metres long, 1.8 metres wide and 3metres high.

The granulator is effectively a large cylinder, on the outside of which are heavy duty blades:simple blade design allows edges to be re-sharpened many times, thereby reducingoperating costs. Routine maintenance is minimised by using an easy-to-remove one-piecerotor for maximum strength. The rotor has a speed of 500rpm: an in-built torque limiterprevents damage if any solid material gets trapped in the grinder.

Raw stock is fed into the granulator, where the tyres are chopped until they are smallenough to fall through the graded sieve at the base of the grinder. The resulting grind isthen conveyed to another grinder, where it is ground even smaller. The multi-stage process


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is shown in Figure 8. There is a minimum of four grinding stages, so the particle size of theresulting crumb is carefully controlled.

Source: Charles Lawrence International Ltd

Fig. 8: Plant process/ layout diagram

Once the tyre is ground to a sufficiently small size, the metal is magnetically separated andsent for reprocessing by steel manufacturers. Any textile present is progressively removedfrom the rubber and then reused elsewhere such as in equestrian paddock areas. Afterremoval of the textiles and metals, the rubber granulate can be more easily graded. Thedifferent granular sizes are suited to different applications, as shown in Table 1.


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Table 1: The preferred granulate siz e by end-useGranulate size (mm) 0.5-1.5 1-3 1-4 2-6 2-8 4-10Polymer content (% ) 56+ 56+ 56+ 56+ 56+ 56+Hardness (IRHD) 60-79 60-79 60-79 60-79 60-79 60-79Bulk density (Kg/ m 3) 432 452 454 470 492 495Sports track XPlaygrounds X Equestrian X Mouldings X X X X X

Key: - very suitable application occasional applicationX Unsuitable application

Playtop mixDuring on-site manufacture, the rubber crumb is blended with a polyurethane binder andwet poured in two layers as a safety surface. A cross section of the surface is shown inFigure 9 below:

Source: Playtop Ltd

Fig. 9: A cross section t hrough Playtop .

The multicoloured top surface is primarily EPDM (Ethylene Propylene Diene Monomer) and istypically 15mm thick, whilst the base layer is a coarse rubber crumb made from recycled

tyres. Both virgin and reused EPDM are used: the reused EPDM is derived from post


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industrial waste streams from industries such as automotive manufacturing, where it is usedfor window and door seals.

The coarse rubber layer can be laid onto loose stone foundation or existing macadam,concrete or asphalt foundation. It is this coarse rubber layer that provides most of thesafety features of the product, whilst the coloured top layer provides a good wear-resistantand fast-coloured coating. Generally the recycled tyres are used in the base element of thecomposite as it only comes in one colour (black).

The association between Charles Lawrence Groups Playtop Ltd and Nike has been inexistence since October 2004, since when parts of a recycled shoe can be included in thesurfaces top layer. Collection points were initially set up at Manchester United footballground at Old Trafford and by Southwark Council in London. Other collection points havealso been established in schools, mainly in the London area, and the Salvation Army is acollection partner through their network of recycling centres.

Originally the topmost wearing layer of Playtop used SBR rubber (Styrene-ButadieneRubber), but this has been superseded because the SBR granular sizes were unreliable andthe material didnt always react well with the binders used in the layers, resulting inoccasional surface weaknesses and failure. Furthermore, the SBR material was notcolourfast and could transfer black marks onto clothing and skin. Currently the wearinglayer contains fine granulated EPDM, which is intimately fixed in the rubber matrix andimparts greater surface strength.

Installation of a play area surface is usually carried out by skilled employees of Playtop Ltd.The ground is firstly excavated and the base compacted to provide a sound base onto whichthe surface can be laid. The edges of the area are defined by kerbstones and anyplayground equipment is then installed.

Once the site has been prepared, a layer of graded stones is levelled out and compactedover the area. This creates a good porous drainage system. A rubber base mixture is thenprepared and wet poured; this mixture comprises a mixture of polyurethane binder andcoarse grained rubber crumb. The thickness of the base will be dependent on the specificsite requirements and this can take account of the required Critical Fall Height required foreach zone of the play area. Typical base thicknesses are between 25 and 125 mm,depending on the required level of injury protection. After levelling the base layer, anyrequired coloured patterns are positioned and cut to size. A top layer comprising fine EPDMcrumb is then poured and hand rolled to a level finish, after which the installation iscomplete.


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Quality Assurance

The Charles Lawrence Group has been ISO 9002 certified since 1995 and the Playtop product range complies with numerous safety guidelines, such as BS EN 1176 (1998) andBS EN 1177 (1998). It also complies with the American ASTM F1487-98 and F1292-99, intandem with the CPSC Public Playground Safety Guidelines.

For compliance with BS EN 1177 (1998), a total thickness of 140mm of Playtop isrequired to achieve a Critical Fall Height (CFH) of 3 metres and only 20mm to achieve aCFH of 0.6m, with various depths in between to cover most CFH requirements.

Technical Benefit s

Surfaces manufactured from recycled rubber offer excellent characteristics for playgroundsand other sporting arenas as they are not only stable and sound, but also offer someprotection against injuries caused by falls and trips. In many ways it can therefore beconsidered as a significant Health and Safety product.

Since the rubber is derived from used commercial vehicle tyres, it also provides an excellent

alternative use for recycled material that could otherwise be at the end of its life cycle. Theuse of an EPDM top layer provides an excellent wear resistant surface that is both durableand long lasting.

In the event of the play surface becoming damaged or vandalised, it is possible to use arepair kit. Two types of kit are available, one for the base layer and one for the top layer.The kit for the base layer uses 2-8mm grade granules and is sufficient to replace 0.3m 2 of base to a thickness of 25mm, whilst the top layer kit uses 1-3mm granules will replace0.3m 2 to a thickness of 15mm. Both kits also supply the required polyurethane binder andinstructions for safe usage.

Cost Benefits

The cost benefits derived from using rubberised playground surfaces cannot be easilycalculated in purely financial terms, as the health and safety benefits derived from usinginjury-reducing surfaces must be taken into account. Furthermore, the prices charged bytyre recyclers for receiving waste tyres are commercially very sensitive and not freelyavailable.


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It is widely accepted that the granulate derived from one tonne of commercial vehicle tyrescan be sold for about 180 a . However, the total cost of a playing area surface is alsodependent on the colour of the top layer and the complexity of the design. Hence theoverall project costs for the Maystar Estate and Magna Science Centre are significantlydifferent: it is believed that the Magna Science Centre took twice as long to complete andcost about 60% more per unit area than the Maystar Estate.

Environmental Benefits

The manufacturing process for the Playtop product range is, environmentally, extremelyefficient, ensuring that the commercial vehicle tyres used in the product range are virtually100% recycled and any non-rubber products are fed into relevant waste recycling streams.

a Please note prices refer to March 2006, and are subject to review


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Details of Parties

Principal ContractorPlaytop Limited

Head Office:Brunel House,Jessop Way,Newark,Nottinghamshire NG24 2ER Tel: +44 (0)1636 615868Fax: +44 (0)1636 610222Email: [email protected]

Northern Office:Newbridge Industrial Estate,Newbridge,Midlothian EH28 8PJTel: +44 (0)131 335 6818Fax: +44 (0)131 333 4154Email: [email protected]
mailto:[email protected]:[email protected]


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This case study was developed for WRAP byOakdene Hollins Ltd

Published by:

The Waste and Resources Action Programm e The Old Academy, 21 Horse Fair,Banbury, Oxon OX16 0AHTel: 01295 819900Fax: 01295 819911www.wrap.org.uk WRAP Business Helpline: Freephone 0808 100 2040

Important warning

The information set out in the above is of a general nature only and not intended to be relied upon in specific cases.

The information does not take account of environmental issues which should be discussed as a matter of routine with theregulatory authorities (the Environment Agency in England and Wales, the Scottish Environment Protection Agency in Scotlandand the Department of the Environment in Northern Ireland).

Consequently, the information contained in this publication is provided only on the condition that WRAP and their sub-contractors will not be liable for any loss, expense or damage arising from the use or application of such information.

Individuals and organisations proposing to utilise any of the practices and methodologies within these publications are advisedto seek appropriate expert professional advice in respect to their specific situation and requirements.

Any errors or omissions contained within the reports are the responsibility of the respective authors.

Waste Tyres Case Study: TYR0008 Playtop play surface 14

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TYR008 Playtop Case Study Final1.5c7f48af