Plastic Materials

In the construction of all types of buildings - for pipes, valves and fittings, heavy duty uses and decorative touches, inside and outside - plastics are building a reputation for durability, aesthetics, easy handling and high performance.

In building construction, plastics abound in plumbing fixtures, siding, flooring, insulation, panels, doors, windows, glazing, bathroom units, gratings, railings and a growing list of both structural and interior or decorative uses. For pipes, valves and fittings, plastics offer superior corrosion resistance and are lighter, easier to install, and more cost effective than their alternatives. Impervious to chemicals and sulphur bearing compounds, plastic piping safely transports everything from fresh water to salt water, and from crude oil to laboratory waste.

Bridge Construction

According to SPI, these qualities have also been combined with plastics' high strength-to-weight ratio to produce materials for bridge construction, including tough reinforcement rods, nonskid surfacing and quickly installed replacement decking. For commercial buildings that contain sensitive electronic equipment, plastics can provide highly protective housing that does not interfere with radio frequency or magnetic waves. From the home to the workplace - and maybe even on a bridge in between - plastics are on the job.

and...Environmentally Friendly Environmental balance sheets consider not only economical use of resources, but also the cost of maintenance during the life of the applications. Since most plastics are either easy to maintain or require no maintenance at all, they also achieve first-class marks in their life-cycle evaluation. Compared with alternative materials in the building industry, plastics usually do better in environmental assessments. In addition to saving resources, the low maintenance cost throughout their life cycle and good recyclability of many plastics used in construction have a positive influence on these assessments. Plastics help reduce gas emissions In a recent survey done by the International Council of Chemical Associations (ICCA), the peak international body representing the global chemicals and plastics industry, it was found that the best options to reduce global greenhouse gas reductions will involve a full life cycle approach to ensure each stage of the value chain provide their optimum contributions. The study found that for every unit of greenhouse gases (GHG) emitted directly and indirectly by the chemical industry, the industry enabled 2-3 units of emission savings via the products and technologies provided to other industries and consumers. The study also found that by 2030, the ratio of GHG emission savings to emissions could increase to more than 4:1 provided certain actions by industry, stakeholders and policymakers. The most significant emissions savings by volume were found to be from building insulation materials (such as expanded polystyrene, extruded polystyrene or polyurethane), agrochemicals, lighting, plastic packaging, marine antifouling coatings, synthetic textiles, automotive plastics, low-temperature detergents, engine efficiency, and plastics used in piping. “Along with our international colleagues, the Australian chemicals and plastics industry is committed to helping reduce greenhouse gas emissions via an innovative and sustainable solutions based approach”, said PACIA Chief Executive, Margaret Donnan. “The groundbreaking study highlights the strategic importance of the chemicals and plastics industry in delivering environmental solutions and enabling real reductions in carbon dioxide-equivalent emissions along the value chain and through lifecycle thinking”. (PACIA, July 2009)

 

Insulation

Plastic insulation systems can also make a significant contribution to noise protection and noise insulation, thus again adding to the quality of life.

Wall covering and Flooring

After pipes and insulation, the third major application area is for wall covering and flooring. Floorings, in particular those made of PVC, have been in use for 55years, and have proved their worth in domestic areas such as kitchens, bathrooms, corridors and children's rooms. They have also made a very valuable contribution in public areas, such as hospitals, sick-rooms, operating theatres, schools, municipal buildings, offices and sports centres.

Window Frames

The fourth largest application area is window frames, which are made almost exclusively out of PVC. This is an application that has developed relatively recently (only since 1965) but, over 44 years, it has secured more than a 50% share of window systems in the major industrialised countries of Europe. Profiles for interior fittings have also secured an important role, accounting for 8 percent of the total plastics consumption in the construction industry. They are used in doors, flooring trim, skirting boards, conduits, and guide rails, covering and decoration. Externally, extruded rigid profiles play a useful role as shuttering, cladding and siding and fencing.

PVC

With the exception of insulation and board applications, PVC is by far the most used plastic in all application areas in building and construction. Many plastics are used where their specific properties can be profitably employed. Depending on the type of material employed, these may include: good hygiene, easy maintenance, heat resistance, thermal and acoustic insulation. They also offer glass-like transparency, abraision resistance, resistance to sunlight, waterproofing, resistance to low temperatures and resistance to acids, chemicals and washing and cleaning agents. These are just a few of the outstanding properties that various plastics can offer in specific applications.

Efficiency

There are also significant savings in cost and energy when it comes to transporting plastic construction materials and plastics promote free movement of building materials in the global market, whereas some traditional materials cannot be exported due to their high weight and enormous transport costs. So today, it is possible for plastic products to be used in any country. They can be manufactured anywhere, even in small markets, because their low weight makes plastic construction products exportable.

Recycling considerations

The building and construction sector is fundamentally concerned with long lasting products and materials, which may well be in place for 40 years before they require replacement.

Many systems have been developed for re-using waste plastics as a central core of panels and large-diameter pipes - with good properties and economics. Plastics come in the form of thermoplastics or thermosets. As thermoplastics (which is the larger part of plastics building products), they can be shaped and re-shaped by the application of heat. The same basic facility can still be utilised for the re-use of recyclates from used products, to manufacture new products. There may be some loss in original properties, from prolonged exposure to sunlight and particularly from re-processing, but all the work so far shows that this can be modified by the use of suitable additives, to "boost" properties back to their original values.

Thermosets are plastics that undergo a chemical change when they are first processed. This gives them their great hardness and strength, but it means that they cannot be re-shaped thermally afterwards. For recycling, however, they can be ground and re-used as a filler. Economics again come into play when considering recycling, and the low original cost of the vast majority of plastics used in building makes it very difficult for re-processed material to be offered at a competitive price unless, possibly, within "closed-loop" systems as already described. A significant development, however, is the increasing use of more expensive technical plastics in high-tech building systems which in time, could provide the building sector with specialised plastics products with a potential.

Plastics recycling and the construction industry

Although the construction industry is not itself a major recycler of plastic (by virtue of the permanence of its structures), it has a key role to play in the sustainability of plastics recycling. A large percentage of recycled plastics is made into extended-lifetime construction products such as geotextiles, insulation, soffits, fascias, damp proof membranes, water drainage, pipes and ducting, building plastic, roof tiles, siding panels, decking, fencing, outdoor furniture, pipes and ducting. What many people don’t realise is that well-known brands like Isotherm® insulation and the multi-purpose geotextile Bidim® are in fact manufactured from 100% recycled PET. Some of the flag-bearers in recycled plastic construction products in Southern Africa are:

Geotextiles

Kaytech Engineered Fabrics, the company that produces Bidim®, converts “green” PET pellets and flake into extruded fibre via a continuous-filament spun-bonding process, followed by needle-punching to give the finished geotextile its structural integrity. According to Production Director Chris Els, Bidim® is the only continuous-filament, spun-bonded, needle-punched geotextile on the market – and the only geotextile to use recycled plastics in its manufacture.

Kaytech began incorporating recycled PET bottles into its nonwoven production in the mid-eighties. Bidim® has been made from 100% recycled PET for the past eight years. Because Kaytech simply melts down the granulated bottles , crystallises the polymer and sp i n s it directly into filaments , the good properties built into the raw materials are retained and the resultant filaments have the strength and durability demanded by civil engineers. Over the past decade, Kaytech has converted more than 18 million kilograms of polyester (rPET) into Bidim® and other civils products.

Insulation

Isotherm® Roof Insulation, produced by South African company Brits Nonwoven, is made from 100% recycled green-coloured PET, is itself fully recyclable, and can be used to insulate geysers as well as roofs and walls. The product does not support combustion, is maintenance-free, requires no protective clothing to install, is Agrément-certified, and is manufactured to South African Bureau of Standards (SABS) standards. Other members of the Isotherm® family are Isofoil, a foil-lined insulator for buildings without ceilings, and Acoustisorb, a light, compressible sound absorption material manufactured from thermally-bonded polyester (PET).

Fencing

In South Africa, PVC from recovered electrical cabling is converted into fence droppers as a replacement for wood and steel. Advantages of plastic in this application include a much longer lifespan, resistance to fire and insects, affordability, light weight and corrosion resistance. Not surprisingly, plastic droppers are a great favourite with farmers and game farm owners in South Africa.

Piping (PVC and HDPE)

Recycled plastic is used to manufacture a variety of piping products for both building and agricultural applications. Where special product performance is required, the piping is made to SABS ratings.

Polyethylene sheeting

Under-roof and damp proof sheeting is commonly made from recycled polyethylene to reduce costs, as are dam linings.

Timber plastic

Don’t be fooled by a convincing faux finish – the “wood” on and in your walls, doors, window frames, decorative molding and outdoor decking and fencing might all be made with plastics-wood composites. Here’s why that’s a very good thing…

More and more architects, designers, builders and property owners are replacing 100 percent wooden building materials with a composite material made from recycled plastic and wood wastes. An important benefit of plastic is its ability to synergistically combine with other materials like wood, metal and glass. The advantages of using plastic-wood composites go far beyond finding a creative way to recycle.

For example, plastic-wood composites are lightweight, easy to install, durable, easy to maintain, resistant to weather damage and corrosion, easy to customize and incredibly strong.

Timber plastic comes in two types: all-plastic and composite. The composite variety (a mixture of recycled plastic and wood) is becoming increasingly popular as a replacement for all-wood building materials. According to the Plastics Federation of South Africa, “Typical wood-plastic composites are made of wood from recovered sawdust, pulp fibers, peanut hulls, bamboo, or straw, as well as from a variety of recycled plastic resins, which bond and reinforce fibers. Commonly used resins include polyester, polyethylene, vinyl ester, modified acrylic, epoxy, phenolic and polyurethane.”

In the all-plastic version, plastic from post-consumer and post-industrial waste is extruded into solid plastic planks and poles. Chemicals are added to make them fire-retardant, sun-proof and attractively-coloured. Timber plastic has numerous uses, from park benches, outdoor furniture, plant boxes, decking and balustrades to recycling bins and even horse stables. What’s more, using ordinary woodworking tools, plastic timber can be cut, drilled, nailed, screwed and routed as easily as wood.

Roof tiles

Another groundbreaking development is the development of a polymer-and-sand roof tile by South African company Resin-Tile. Mixed post-consumer plastic waste is blended with sand to create a tile that is not only eco-friendly, but boasts other features like l ow mass; long life; easy fitment; resistance to sun, water, fungus, water and temperature extremes; low thermal conductivity and excellent noise and heat insulation.

Civils construction

Recycled PET finds a life-long application in civils applications such as drainage and filtration, road maintenance and rehabilitation, water and waste containment, separation of fill material and reinforcement. Recycled plastic plays a major role in Kaytech’s drainage and filtration range. Examples include its 100% PET Bidim® geotextile, its recycled plastic Infiltration Chambers, and its 50% HDPE Flownet and Geopipe (and combinations thereof). Sealmac, used for road maintenance as well as water and waste containment dams, is also 100% PET.

“ The stringent specifications that the food industry and bottle manufacturers have placed on the PET raw material, allowing for the production of thin-walled, food-contact-approved containers, allows Kaytech to produce a high-quality nonwoven which ultimately meets and exceeds the civil industry’s standards,” says Kaytech’s Garth James.

Another successful application of recycled polyethylene (applied in India for example) is the mixing of shredded plastic with tar, enhancing both road performance and safety.

Aggregate in non-structural concrete

While not yet viable in most developing countries, there is considerable scope for the use of granulated plastic waste materials as aggregate and filler in masonry mortar and outdoor plaster. In addition to the environmental spinoff of recycling plastic, plastic in mortars and plasters offers numerous other advantages – low thermal conductivity; low bulk density; reduced wear of mixing and pumping equipment; a low E-modulus in relation to strength (which reduces the possibility of cracking).

PVC in building

PVC is by far the most widely used polymer in building and construction applications worldwide. Apart from its strength, cost-effectiveness, ease of installation, excellent thermal properties and resistance to weathering, rotting, chemical corrosion and shock, PVC has an exceptionally long lifespan. PVC pipes, for example, have potential in-service lives of up to 100 years. European studies of window profiles and cable insulation indicate that over 60% of them will have working lives of over 40 years ( www.pvc.org). Medium and long-term applications account for some 85 per cent of PVC production in the building and construction sector in Europe, and a growing percentage of long-life applications in Africa.

In Europe, the PVC pipe, flooring, roofing membranes and window industries already have schemes developed which are aimed at collecting and recycling these products when they have reached the end of their useful life (see www.vinyl2010.org). The PVC industry supports an integrated waste management approach, which aims to maximise the efficient use of raw materials and utilise the best end-of-life treatment option for each waste stream.

The integrated approach to waste encompasses (in order of preference):

• Prevention via reduction at source – minimising the volume and weight of waste at the production stage.
• Re-use – providing an extended life for certain products.
• Recycling – making new products out of used goods.
• Energy recovery – harnessing the high energy value of spent plastic goods to produce light, heat and power.
• Landfill – a last resort for non-recoverable products and the residual waste from recovery operations. PVC can safely be deposited in landfill if no recovery solution is available.

The challenge for the building industry in South Africa is to find ways of recycling plastics products generated by the industry.

Plastics Recycling Advantages Cost: While the cost of recycled plastics is not always significantly cheaper than virgin plastic, their total lifetime cost is lower than other materials (and even virgin plastic) owing to their durability and minimal maintenance requirements. At times when virgin polymer prices are high, recycled plastics costs are significantly advantageous. Strength & Versatility: Plastic has a high strength-to-weight ratio, and is used in an increasing range of construction applications – including as an aggregate for concrete and in aspects of bridge construction. Recycled plastic construction products typically meet standards specifications, so are as safe, durable and trustworthy as their virgin-plastic equivalent. Preference in Tenders: The use of environmentally sustainable products is going to become a major criterion in the ‘green’ rating of built environment professionals and contractors, as well as in the awarding of public sector contracts. In the UK, even private sector organisations are beginning to give preference to contractors with a reputation for using recycled products. CONTRIBUTION TO THE ENVIRONMENT: As the use of recycled plastic products rises, so more demand is created, preventing plastics from being discarded. There’s also a strategic payback to enviro-consciousness: it tells the world that you care for the environment, which is bound to generate goodwill towards your business.

 

Apathy is not an option

The challenge to the construction industry is to formally and effectively collect waste from initial/new building construction (packaging, off-cuts, left-overs, etc.); from maintenance and refurbishment projects; and eventually at the end-of-life of buildings. In addition, the industry can create pull-through demand for recycled plastics by “buying green” where possible. Lastly, since we all live in homes, we need to take a fresh look at what we call ‘waste’ and make sure it gets back into the manufacturing system. Remember – plastics are too valuable only to use once.

More information on recycling of building waste and contacts for recyclers can be obtained from SAPRO (the South African Plastic Recycling Organisation) email address Annabe@absamail.co.za .

Looking for motivation to recycle? Remember that today’s plastic bottles, bags and product wraps could be tomorrow’s durable deck. Plastic bottles typically go curbside. Plastic bags and wraps can be brought back to many grocery stores that collect these materials for recycling.