Plastics meet chilled water
Metal is still far and away the dominant player in pipework for building-services applications, but one company has successfully established a plastic-based system for chilled water. Ken Sharpe has the details.
With metal theft a phenomenon that is no longer focused on copper but now also extending to iron and steel, installers are looking more closely at plastics for plumbing. And that attention is welcomed by Darren Myers, sales and marketing director with George Fischer in the UK as contributing to ‘plastics starting to win the fight’ against the overwhelming dominance of metal.
Darren Myers puts the UK market for plastic systems at around £8 million a year, compared with £ VERY HUGE for traditional materials.
Once installers start to look at plastic pipework systems, however, they quickly become aware of its inherent suitability for carrying chilled water in secondary air-conditioning systems and for process cooling. ‘Plastics is perfect for chilled water,’ asserts Darren Myers.He highlights a host of benefits for metal over plastic. Its price being less volatile that copper and other metals is one that tends to attract the initial attention. Another is its low theft value. Moving to installation benefits brings in 40% less labour than traditional materials and 40% less heat loss.
However, it is the suitability of plastics for chilled water that has been acknowledged by George Fischer in the development of its Cool-Fit range covering pipe diameters from 16 to 315 mm. Cool-Fit is a complete system for secondary refrigeration and cooling and comes complete with valves and fittings. There are also fittings for connecting to metal pipework and chillers.
Testimony to the how appropriate Cool-Fit is for chilled-water systems is the range of signature installations for which George Fischer has prepared presentations. They include offices for the City of Edinburgh Council, a £1 million contract involving pre-insulated and encased Cool-Fit Plus in sizes from 20 to 315 mm.
Another project is Queen Alexandra Hospital in Portsmouth, a £650 000 project that used Cool-Fit ABS pipe, fittings and valves in sizes from 63 to 225 mm.
Cool-Fit also finds application in data centres such as the Hutchinson Data Centre in Manchester. The rapid installation capabilities of Cool-Fit were the key to its selection for this project. It comprises over 2 km of Cool-Fit ABS piping that was installed in half the time that would have been required for steel pipework. There are four flow and return lines in 225 mm and four in 160 mm.
Demonstrating the installation benefits of the light weight of Cool-Fit is a project for GCHQ at Cheltenham. The requirement was to install 200 m of pipe below floor level in eight days. The pipe had to be manhandled, which would not have been possible with metal; equivalent 10 cm steel pipework is about 15 times heavier than Cool-Fit. Preinsulated and encased Cool-Fit Plus was installed by four people in the eight days allowed. An additional benefit was the cold solvent-weld system, avoiding the need for a hot-works permit and firemen to be in attendance.
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| The light weight and ease of installation of the Cool-Fit system requires 40% less labour. |
The Cool-Fit range comprises three types of pipe.
• Cool-Fit ABS is uninsulated.
• Cool-Fit Lite is preinsulated with Armaflex insulation, but without an overall cover. It is designed for indoor installation.
• Cool-Fit Plus is preinsulated using polyurethane foam and has an overall casing that is suitable for outdoor installation. It can resist ultra-violet light and bird damage.
The external casing makes Cool-Fit Plus easier to support using clamps that fit round the casing. This feature was beneficial for the GCHQ project, even though the pipework was indoors.
Joints are made using connectors inserted into the internal bore and solvent welded. In the case of preinsulated pipe, the connection zone is left uninsulated until the system has been checked for leaks. Insulation collars can then be inserted into the thin gaps.
Finally, installation time is shortened by there being no need to flush the system, although corrosion inhibitors will still be needed to protect metals component such as heat-exchanger coils and sections of metal pipework.
And in keeping with modern practice, the system lends itself to prefabrication.
The Cool-Fit concept is supported by online technical design advice — including calculations of energy loss and temperature differences, as well as on-site advice and installation training.
Let’s give the last word to Darren Myers: ‘Installers who have been metal heads for many years are increasingly turning to plastics.’
