Theme: plumbing and drainage
As designers become used to the changes in regulations for plumbing and drainage, there are signs of a more sustainable approach within the sector, while harmonisation of European codes and the introduction of CE certification have opened the gates to overseas products
In the past year there has been little change in the codes or regulations for drainage and plumbing. This is will be a welcome relief for designers, as they can now reflect on, and possibly learn from, the recent raft of alterations.
A more sustainable and European flavour has already started to show itself within the industry and there are clear signs of how this will shape the plumbing and drainage industry in the coming years.
Some organisations have produced supplementary guidance to accompany the codes and enhance system design further.
For example, Hydraulic Research has published Hydraulic Design of Paved Areas, a document about the draining of large flat areas. This addresses the over-simplification of rainwater drainage guidance contained in the recent revision to BS EN 12056 and should ensure that designers can determine accurately storm-water run-off flows from large paved areas, enabling them to design more cost-effective drainage systems.
The desire for a more sustainable approach to drainage systems was the backbone of last year's revisions to Part H of the Building Regulations. These changes have resulted in additions to the large number of best-practice manuals published by CIRIA.
The most recent is Source Control Using Pervious Surfaces. This is an ideal reference for the ever-increasing growth of large paved areas, which accompany out-of-town retail development sites.
Sustainable Urban Drainage Systems (SUDS) is in the same vein, and the systems are now being pursued actively by environmental and planning authorities alike. It is important that this type of design reference material finds its way into all responsible designers' libraries.
During the past 12 months, the Concrete Pipe Association has been preparing designers for the new health and safety requirements for access to manholes and chambers.
This information and other developments can be found on its excellent website (www. concretepipes. org).
One of the more interesting recent government initiatives is the Enhanced Capital Allowance scheme. Aimed at reducing carbon emissions, this tax scheme gives developers 100 per cent first-year tax relief on energy-efficient products incorporated into construction. Although it was initially aimed at the heating and air-conditioning sectors, there are strong indications that plumbing products will soon be added to the approved-product lists. To keep up with the developments on this front, visit the dedicated website at www. eca. gov. uk.
Performance-based approach As any designer with overseas experience will know, one of the most satisfying aspects of UK regulation is its performance-based approach. This is often overlooked, as some designers refer to prescriptive clauses in Codes of Practice as a safeguard and as offering a perceived robustness to a design. While it is always vital to use Codes of Practice as a reference to key aspects of a design, it is also important not to use clauses blindly as a certainty for best practice.
Quite often, that blind approach leads to missing the real value that can be delivered to clients. Codes often take a decade to redraft and over this time there are advances in technology, which can benefit projects immediately. If the code is followed too tightly, the project can miss an opportunity to deliver real value. If developing technologies are overlooked during the code drafting stage, they could be excluded from consideration for another decade.
Harmonisation of European codes has opened up the market to allow tried-andtested overseas products to enter the home market. Acceptance of new technology also gives UK manufacturers a clear message to continue research and development of new products, in the knowledge that the results of their investment will be evaluated and eventually specified by designers.
Recognition of individual countries' manufacturing standards, and the introduction of CE certification, have removed a great deal of suspicion over inferior imported products. Agrément certificates such as BBA have helped manufacturers and designers to get new products incorporated into plumbing schemes.
One challenge for engineers and designers is to demonstrate the value their designs deliver to clients. Real value can only be gained through benefits that are realised during the life cycle of the building.
Selection of appropriate materials is an important aspect of providing value to clients. There is an enormous variety of new and traditional products, which, through correct and considered selection, can offer real benefits at all stages of the project.
As materials become a smaller proportion of the overall installation cost, the need to reduce the labour element has led to innovations such as speed-fit fixing and jointing methods.
Putting the pipes in Pipework installation is by far the largest element of the construction programme for plumbing systems. Traditional jointing methods are being replaced by couplings, which can be sealed with quickly acquired skills delivered by short site-based training sessions. Development of emerging technologies has focused on this aspect and has delivered products that offer faster installation times to offset any higher material cost.
Much of the progress in pipe fitting has been due to the development of the humble O ring. This gained unintentional notoriety as the cause of the first space shuttle disaster, but has found favour with manufacturers of pipeline jointing.
The overall specification of pipeline materials can be the most important factor in achieving value on a project. As projectspecific demands will always be unique, selection of materials should be given a high priority during the design.
Copper is one of the most versatile pipeline materials available. Yorkshire Copper Tube has long been involved in supplying pipes for water, gas and drainage systems. Pipes are available in a large range of diameters, in straight lengths or as long coils. As well as plain finished pipe, the Kuterlex brand incorporates a factoryapplied plastic coating. This coating gives extra corrosion resistance, making the pipe ideal for concealment in building structures or for underground systems. The variouscoloured finishes also allow ease of identification of the content. This type of product has long been available but has now exploited the water-regulation and health-andsafety requirement of service identification as a new application for a tradition material.
In the commercial sector, copper installations have been gaining a share of the tradition steel market, with the introduction of jointing techniques developed for rival materials. Yorkshire Fittings has introduced a mechanical compression-jointing system, which was originally developed for ferrous materials. The Presfit system is available for sizes up to 108mm.
Traditional highly skilled and meticulous soldering or brazing techniques are replaced by a flame-free joint, which is easy to learn.
The fitting is slipped on to the pipe spigots, and then the ends of the fitting are compressed on to the pipe wall by electromechanical jaws.
Home front Savings can also be achieved in more domestic installations. For smaller-diameter pipes, IBP has continued to provide 'push-fit' demountable couplings. These have the advantages of longevity, pressure rating and durability of traditional non-manipulative fittings, but with the added benefit of a simple jointing and dismantling method. They also give a flame-free joint and have a smooth, tube-like appearance, which makes them acceptable in exposed installations.
As competition intensifies in the pipe and tube sector, the copper manufacturers have strengthened their trade association. In addition to the support and guidance available from the company websites and representatives, information on all copper applications is also available from the Copper Development Association at www. cpa. org. uk or www. ukcopperboard. co. uk.
As with most other new jointing technologies, it is the humble O ring that has enabled the growth and development of push-fit fitting types. As this technology has not yet found its way into the gas market, users of copper can rely on their traditional skills with more familiar flame-solder jointed couplings. Additionally, recent guidance from Water Regulation Advisory Service has suggested that where pipes are to be concealed in a masonry structure, they should be jointed with soldered fittings.
New jointing techniques have also been introduced for smaller-diameter water pipes, used in the buoyant residential sector.
It is in this sector that metallic systems have seen their traditional markets eroded by the establishment of thermoplastic systems. The development of the push-fit O ring was pioneered in the thermoplastic market.
Although it took some time for installers to accept such low-skilled techniques, the continual development of the fitting type has overcome initial concerns. Their introduction into the metallic pipe sector has confirmed that the technology is here to stay.
As the first entrants into the housing market, developers of underground service polythene pipes have not rested on their laurels. Durapipe has continued to introduce methods of enabling its products to be installed more efficiently. Recently it introduced the Philmac brand, which has a Universal Transition Coupling. This mechanical fitting is developed not only to join Durapipe products, but also to ensure that it can be used as a transition to other pipe systems. A full range of straight and bent connectors is available, as well as T-pieces, which make them ideal for new or repair work.
In today's underground water supply market, it is hard to see where a thermoplastic pipe system would be inappropriate. But as government puts pressure on housebuilders to use more redundant brownfield sites, there are increasing problems of contamination by previous site owners. In some cases the contamination is so widespread that site removal and landfill disposal are prohibitive. In these circumstances, plastic service pipes could allow ground contaminates to pass through the pipe wall and contaminate the water supply. To overcome this problem, Cannock-based GPS has introduced a barrier pipe system called ProtectaLine. This has recently been augmented with a range of compression fittings, which reduce the time and materials involved in joint preparation.
Living quietly Inside the home, thermoplastic systems have gained acceptance not only with installers but with homeowners, too who have realised that the creaking and ticking of hot-water systems is all but eliminated due to the smooth soft nature of the pipe. Where pipes come into contact with structural elements, they have a tendency to glide against the surface and not give rise to noise during heating and cooling.
Hepworth, which offers the Hep 2O system, is one of the longest-established suppliers in the above-ground water pipe market.
The pipe's external diameter is compatible with traditional copper pipe systems, so it can use its own push-fit couplings to join to and extend existing systems. The pipe system comes in straight and coiled lengths, in a range of sizes from 10mm to 28mm. Aimed at the residential market, this polybutylene system is ideal for concealing in modern housing construction to provide both water and heating-system installations.
Developments in other material sectors have allowed further reductions in installation times for coiled plastic systems. As increased U-values of buildings reduce heating loads, radiator pipes have become small enough to be concealed behind wall linings.
Since the pipes are usually supplied in long coiled lengths, the WRAS guidance mentioned above is not applicable, as joints can be all but eliminated from voids.
Underfloor heating The market has also seen a growth in underfloor heating systems in modern buildings.
When underfloor systems were restricted to commercial buildings, Wirsbo developed a cross-linked polyethylene barrier pipe (PEX) for this market. The barrier pipe prevents the ingress of air, which can pass through the walls of the pipe. During manufacture, the inner and outer walls are separated by a thin impervious lining to prevent the passage of air into the pipe.
Once established as a market leader, Wirsbo turned its attention to the water-services market with this technology. The system uses mechanically jointed couplings that do not restrict the internal bore of the pipe. The pipe is manufactured to BS 7291 and is designed to offer a minimum of 50 years of service life.
A product range introduced into the UK by Swiss company Henpipe is one of the first to have developed a plastic system for gas distribution. The gas pipe is colour-coded yellow, so as to be identified quickly as a non-water system. This approach means installers can procure their system materials from a single source and benefit from speedy installations. The pipes have a plastic surface and bore, with an aluminium middle core, which gives the pipe rigidity when it is surface-mounted. This core is more rigid than required for an oxygen barrier and gives the pipe more rigidity. The Henpipe range is available in a large range of diameters and is available from stockists around the UK.
As pipeline technologies become more akin to cable installations, it will be interesting to see if fixing methods will cross over from the electric sector. In commercial buildings, traditional pipe fixings account for a large proportion of the installation time. These accepted bracketing systems are inappropriate for coiled flexible systems, but the transfer of technology could be the catalyst for dynamic growth in the use of plastic systems away from the residential sector.
One manufacturer that has successfully introduced a composite system into the commercial sector is Geberit. It has overcome deformation problems by producing a composite pipe, which contains an aluminium tube between the inner and outer walls to provide a semi-rigid system. This combines the advantages of thermoplastic and metallic systems. The Mepla range goes beyond most competitors to include larger diameters normally found in larger residential and commercial developments. It also provides the same system in flexible coils for the smaller diameters. It is claimed to be more resistant to limescale deposits and is better suited for installation in areas where aggressive water can lead to accelerated corrosion. As it is supplied in straight lengths, bracketing can be at greater distances, so savings can be made in site preparation.
Geberit also has an interest in the plastic drainage sector. The Pluvia high-density polyethylene (HDPE) system has established itself in traditional and specialist markets.
HDPE was originally used for drainage of chemical waste in laboratories. The fusionwelded fittings provided a safe method of conveying and containing toxic wastewater.
In the early 1990s, Geberit entered the siphonic rainwater market, as Pluvia was an appropriate material to withstand the increased system operation pressure to which these systems could be subjected.
Foothold in the UK After being used in Europe as a soil and waste system for a number of years, Pluvia has now gained a foothold in the UK market.
The fusion-welded jointing techniques are now a recognised and accepted method of jointing for system installers. As mentioned so often with modern pipework systems, training is a large part of Geberit's approach to maintaining high-quality installations and bolstering the company's reputation.
The ability to assemble pipework off site is also a positive step in the move towards the prefabricated aspiration the government has set the industry. Its recent purchase of Terrain has demonstrated Geberit's commitment to the UK market and has given it access to the traditional uPVC sector through the Caradon Terrain brand.
Steel pipe is still one of the most utilised pipe materials for heating, cooling and gas systems in commercial buildings. Whereas galvanised steel has long been out of favour for water-system installations, it is still used for prefabricated soil-pipe installations.
Konaflex has been supplying this sector of the market for nearly 40 years and is now the market leader. The pipe components are welded in steel, then hot-dipped galvanised.
The main advantage of this approach is the homogenous product created. Where pipes need to be cast into structural building elements, it is vital the pipework is of the highest integrity. Joints contain no rubber gasket seals, reducing the risk of leakage once the pipe has been cast in. The welded pipe and joints are capable of withstanding far higher pressures than experienced in soil systems, and the post-applied galvanising coating further enhances the lifespan of the product.
Konaflex's factory-based skills and site surveying experience mean it would benefit from any move towards off-site fabrication.
Not restricted to soil-pipe systems, Konaflex also uses its plumbing knowledge to deliver prefabricated plumbing component sets for use in offices and PFI projects.
In water-system installations, one of the main disadvantages with galvanised steel is its reactive nature when combined with copper tubes. Copper tubes became the market leader at the expense of galvanised steel, but as plastics are now becoming more common, there are still possibilities for the reintroduction of steel in the commercial sector.
The difficulty of jointing stainless steel led to the development of a simplified method of compressing fittings on to pipes mechanically. The fittings contain an internal rubber ring, which seals the cavity between pipe and fitting. This has successfully crossed the material divide and is now used on copper and steel pipes.
Stainless steel gets reasonable Stainless steel has often been associated with high-priced, corrosion-free systems, but in recent years the unit cost has fallen to near that of traditional materials. Blucher has been extolling the virtues of this material in the soil and waste sector for years. Originally aimed at the exposed architectural rainwater market, the Europipe product has now gained the support of designers and specifiers requiring a quality product.
More recently, use of Europipe has increased, due to the awareness of overall life cycle cost. Independent tests have shown that it is also cost-effective for use as a soil and waste system. The lightweight push-fit system enables installers to reduce bracketing assemblies and reduces installation time significantly on a metre by metre basis, compared with other metallic systems.
Even when compared with thermoplastic systems, some installers have found Europipe offers the best overall value for wastewater disposal systems. Although Europipe did not hold a British Standard certification originally, it obtained a BBA approval for above-ground drainage systems after a strict testing regime.
Installers have welcomed the introduction of a flexible stainless steel system for the gas industry. Tracpipe makes a pipe that allows the forming of bends without the need for specialist tube formers or fittings.
Due to the concertina form of the pipe wall, the radius of the bends is not restricted to the diameter size. Short and long-radius bends can be formed by hand as appropriate. As the jointing system does not rely on fluxbased compounds, there is no risk of jointing materials entering the bore of the pipe.
This thin-wall, lightweight, self-supporting pipe can be threaded through voids in a manner similar to plastic pipes. The pipe also benefits from a colour-coded protective sheathing for easy identification.