PB-1 withstands hostile environment

Pipe lines – Frost protection and insulation

Polybutene-1 products could alleviate the risk of burst pipes this winter.

Professional Heating and Plumbing Installer (PHPI)
Dec. 2003

Every year hundreds of homeowners have to file insurance claims for the cost to repair the damage caused by burst pipes during cold spells throughout the British winter. There are many ways that this costly problem can be avoided such as ensuring that pipes are well insulated. It is becoming widely recognised, however, that the most effective means of avoiding this common problem is to install plastic pipes.

Plastic pipes have many advantages over more traditional materials and the plastic increasingly considered as the most versatile for piping Systems is Polybutene-1 (PB-1).

In its most simple homopolymer form, the balance of its properties make PB-1 the technically preferred material for the production of pressurised hot and cold water pipes. In contrast to competitive thermoplastics used in these applications, performance modification via compounding, cross-linking or copolymerisation is not necessary for Polybutene-1 pipes to fulfil the stringent performance standards applied to their use.

PB-1 pipes remain functional over a wide range from severe frost conditions to continuous use at temperatures up to 70°C. They meet stringent performance standards dictated by national and international accreditation bodies based on specific BS and ISO/CEN Standards, which demand a design lifetime of more than 50 years. In terms of frost protection, the elastic properties of PB-1 ensure that when water freezes in the pipe the ensuing expansion is accommodated by an increase in the pipe wall diameter, minimising the possibility of bursting. The pipe then returns to its original dimensions when the frozen water melts.

Another advantage of PB-1 is its low thermal conductivity in comparison with metals. For instance, it is approximately 2,500 times less thermally conductive than copper and therefore in sub-zero temperatures water running through a PB-1 pipe will take significantly longer to freeze than in a comparable copper pipe situation. A consequence of this much lower thermal conductivity is that PB-1 piping Systems will require less external insulation for protection from freezing conditions in order to maintain a continuous water supply.

PB-1 pipes are also suitable for all water supply types irrespective of pH and are highly resistant to corrosion. Soft water can lead to corrosion in metallic piping systems, which progressively weakens the pipe wall, making the pipes more susceptible to bursting following a period of freezing weather.

A prime example of the use of PB-1 piping Systems in a hostile climate can be seen in the ambitious Santis 2000 Expansion project. The project involved the renovation and expansion of the communication and tourist facilities on the Jungfrau, the highest peak on the Alpstein massif in eastern Switzerland. At more than 10,000 feet above sea level, and at present the highest building site in Europe, the pipes had to be able to withstand temperatures of -30°C and wind speeds up to 200 km/h. "The Santis project was very demanding and required a piping System that was extremely flexible, frost resistant and easy to assemble given the location" explains Jürgen Fluck, of the Polybutene Piping Systems Association (PBPSA). "PB-1 was perfect as it is easy and lightweight to transport and very straightforward to install using automated electro-fusion. An added
advantage was the fact that large Segments of the pipes could be prefabricated off site, making the installation very quick, an important consideration as the facility remained open to the public throughout the development work.

"The pipes have been very successful indeed, even in temperatures as low as -30°C." The Santis project certainly represents an extreme in PB-1 piping Systems application. In the UK, however, PB-1 piping Systems are becoming the preferred choice within the new house build sector, where the majority of building contractors have already made the switch.

The PBPSA has been formed to underline manufacturer confidence in Polybutene-1 and its suitability for flexible piping Systems.