BSEE


COVER STORY


A flexible pipework solution for refurbishment


Here, Glen Peters, technical support manager at Viega looks at the benefits of mullayer pipe and how it can help overcome the challenges of maintenance work and refurbishment projects.


complicated further if the work has to be completed while the building is still occupied, meaning speed, safety and minimal disruption are just as important as the quality. However, multilayer pipe has a number of benefits that can help overcome these challenges.


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The advantages of mullayer pipe Multilayer pipe is a composite material


manufactured from aluminium and thermally resistant cross-linked polyethylene (PEX). The aluminium core delivers the durability and ensures the pipe retains its shape, while the inner and outer PEX layers protect from corrosion. Multilayer pipe is very versatile and can be used for similar applications as copper pipe such as heating systems, hot and cold-water pipework and potable water installations. In fact, engineers that are familiar with press connections for metal pipe will find the installation of multilayer pipe very similar.


The construction of the pipe gives it a large degree of flexibility and allows it to be easily and accurately shaped using hand-held tools without buckling or kinking. This means it can be bent rather than cut to achieve a change of direction and therefore allows longer pipe runs with fewer connections. Multilayer pipe, such as Viega Smartpress is supplied in lengths of up to 200 metres and can be used directly off the coil, so


he maintenance and refurbishment of pipework in building service systems can be challenging due to the need to work within confined spaces or route the pipe around existing structures. This is


those installing it can simply cut the pipe to any length that is required. Not only do longer uninterrupted pipe runs reduce the risk of a leak in the system but also makes routing pipework around complex features easier and less time consuming. In confined spaces the ability to minimise the number of connections makes it easier to achieve what is required. In addition, compact press tools such as Viega’s Pressgun Picco simplify the process of pressing the connections that are needed.


A further advantage of multilayer pipe for maintenance and refurbishment is its compatibility with metal pipe. It is possible to connect multilayer pipe to existing metal pipework using specially designed press connection adapters. There are options available that allow both sides of the connection to be pressed or for the new pipework to be connected to existing threaded pipe if required.


Further important considerations for maintenance and refurbishment are safety and minimising disruption, especially where the building will still be occupied throughout the work. The simplicity of multilayer pipe installation means that significant time savings can be achieved. Further, systems such as Viega Smartpress replace the traditional O-ring construction with a robust and durable Polyphenylsulfone (PPSU) support structure that further streamlines the process. This means that up to a 30% time saving can be achieved when compared with alternative systems.


Multilayer pipe eliminates the need for heat to be used at all during the installation and the tools required to cut, shape and connect the pipe present no additional hazards. There is also minimal noise, no fumes and no mess during the install. These benefits combined with the reduced risk of leaks mean that it is ideally suited to renovations in older buildings where any risk of damage to the building fabric is unacceptable. An example of how it can minimise disruption is the upgrade to the heating systems of nine care homes carried out by FHS Commercial in the North East of England. FHS Commercial was contracted by the homes’ management team to install new gas boilers and heating systems throughout the properties. The existing heating consisted of inefficient electric storage heaters that were no longer fit for purpose.


Due to the nature of the buildings and the needs of the residents, the installation had to be carried out while the homes were in full use. FHS Commercial chose to utilise a multilayer pipe system and selected Viega Smartpress as a quick, clean and safe solution that would provide ease and speed of installation to minimise disruption.


12 BUILDING SERVICES & ENVIRONMENTAL ENGINEER MARCH 2021


Choosing the right products However, as with all materials, it is important to


select a high quality multilayer pipe system as not all products are manufactured to the same standard. A lower quality pipe may buckle instead of bending as expected or may fail under pressure resulting in costly and disruptive remedial work after the project is completed. Also, any material that is used in the delivery of potable water must have been tested and approved to certify that it does not contaminate the water.


It is also important to consider the design of the pipe connections to ensure they will not affect the performance of the system. Fittings that cause additional friction or deform the pipe when pressed, reducing the internal dimensions, can cause lowered system pressures and flow rates. This is especially true for large installations where the quantity of the connections means there is a significant cumulative effect. Expertly engineered fittings will avoid this deformation and should also include internal deflectors that have been specially designed to optimise the flow of water to reduce the overall resistance. Fittings with very low zeta values, such as Viega’s Smartpress system can reduce pressure loss by as much as 80% compared to standard designs. A standard design brass degree elbow connector with a zeta value of 17 will result in a pressure loss of 340mbar at a flow rate of 2m/s. Viega Smartpress offers a flow optimised alternative with a zeta value as low as 2.7, resulting in a pressure loss of only 54mbar at the same flow rate.


Finally, the press connections should include features to help identify any unintentionally unpressed connections. If left unpressed, some connection products may appear to be sealed throughout initial testing and only begin to leak when the system starts working. This has the potential to cause significant damage to the building and inconvenience for the occupants. Choosing a product that includes features to highlight any missed connections immediately can avoid the need for costly remedial work. For example, the SC-Contur technology in Viega press connections allows unpressed joints to be clearly visible during leak testing or when the system is filled for the first time.


Multilayer pipe is a versatile alternative to traditional pipework options and has particular benefits for maintenance and refurbishment due to its ease and speed of installation as well as improved safety and cleanliness. However, it is essential to select a high quality product to ensure system performance and long term durability.


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