POLYBUTYLENE (PB)
Polybutylene is a polymer based plastic belonging to the family of polyethylene polymers. Polybutylene has similar characteristics to LDPE but with greater impact strength and heat resistance. The pipe is highly flexible, similar to XPE pipe, but has the advantage of being cheaper to mass produce. Jointing is by mechanical means, either with a mechanical grab socket and compression fitting or metal clamp ring system. Polybutylene does not have the same resistance to chemicals as other polymer pipes, particularly petroleum products, and has a susceptibility to constant high temperatures above 60°C.

SUMMARY
There can be no doubt that plastic use within the discipline of hydraulic services is increasing. UPVC is now the norm on many major commercial projects for sanitary plumbing, particularly large multi-storey residences. Internal rough-ins are now almost all done in either XPE or PB pipework with only main flow and return lines remaining in traditional copper pipework.

Polypropylene pipes are being specified for grease waste lines, while other systems on the market are not suitable for continuous hot water flow and return circuits. MDPE and HDPE pipes are beginning to cut into the PVC sanitary pipework market thanks to their better acoustic properties. Nylon systems have long been available for gas pipework and pneumatic systems.

It is important for us as consultants to recognise the uses and limitations of different types of plastic products on the market. It is also relevant to use products that meet the requirements of DIN Standards and Australian Standards, and have applicable authority approvals such as Watermark where called for. Consultants need to ensure that contractors are properly trained on installation procedures for the various products on the market, and that seperate product systems are not mixed during the installation. Over the last few years there have been many stories circulating within the industry about product failures. A great many of these can be put down to poor installation practices, lack of supervision or incorrectly specified products. By keeping within the product limitations and following manufacturers installation procedures, the client, contractor and consultant can be assured of a sound pipework system capable of meeting the demands of today's construction industry.

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Presented Courtesy of The Association of Hydraulic Services Consultants Australia Inc (AHSCA)
Written by Stuart Hunt
"Plumbers Protect The Health Of The World."