The common issues faced by sanitary engineers in high-rise buildings are velocity of the flow and the pressure on the relief pipe, according to Gabriel Nassar, managing director, Geberit’s (rep. office Gulf). However, in reality, Nassar says that the biggest issue is value engineering. He adds: “[The issues are] how to decrease the space in the shaft, how to use less pipes and fittings, and how to use less products to reduce building costs.”
Geberit has launched a technology that will help in resolving the aforementioned issues. The Geberit SuperTube drainage system consists of Geberit PE Sovent fitting, Geberit PE Bottom Turn Bend and Geberit PE Back Flip Bend. Nassar says: “Geberit has optimised its tried-and-tested Sovent fitting with the new SuperTube technology that allows direction changes to drainage networks in high-rise buildings, thanks to improved hydraulics, thus saving space in both vertical and horizontal directions. This is because of SuperTube’s smaller pipe dimensions and zero additional ventilation requirements, not to mention its horizontal, no-slope pipelines.”
The Geberit SuperTube allows the stacks to be installed without the need for any parallel ventilation pipes and in narrow ducts with small pipe dimensions. The horizontal installation with zero slope makes it possible to fasten ceiling suspensions in place just a minimal distance away from the concrete floor. Nassar says: “With Geberit SuperTube you get an optimised system using less space and less products which addresses value engineering by improving the function of the system, reducing the cost of products and decreasing the space required for the drainage system.”
Dwelling on how the SuperTube works in conjunction with the Sovent fitting, Nassar says: “The Sovent system already facilitates drainage in high-rise buildings even without the need for parallel ventilation pipes – except in the case of direction changes. With Geberit SuperTube, this issue is a thing of the past. In the hydraulically optimised Geberit Sovent fitting, the water is fed in such a way that there is no hydraulic congestion when it is supplied from the connections. The Geberit Sovent fitting causes the outflowing water to rotate and flow along the pipe wall with a stable column of air in the centre.”
The HDPE Sovent system is used for an economical and space-saving configuration of stacks in buildings with more than five floors (high-rise buildings). A continuous air column is achieved with the Geberit HDPE BottomTurn bend. “A change in direction causes the wall of water to break and the annular flow to become a layered flow without disrupting the column of air,” Nassar explains.
This direction change of the water in the HDPE BottomTurn bend results in significantly lower impulse losses than in conventional directional changes. This means horizontal pipelines can be used for up to 6 metres in length without any slope and with dimensions of d110. At the end of the offset, the layered flow of waste water is directed back into a swirling annular flow by the Geberit BackFlip bend and the column of air remains intact.
Hydraulic pressure compensation in a stack system is an extremely complex matter, Nassar points out. “Each stack concept is characterised by individual properties,” he elaborates. “The capacity of the stack and ventilation system is dependent on the flow capacity of the appliances, their simultaneous drainage pattern, the branch fitting inlet configuration and the drainage concept of the building. Overpressure and negative pressure in a drainage system must be limited in order to ensure the water seal in the trap.”
“Very high negative pressure values can arise in conventional main vent stacks. The negative pressure arises due to unfavourable flow behaviour between the stack and the branch discharge pipe. This unfavourable flow behaviour leads to a hydraulic blockage in the stack that prevents the air from circulating.”
The Geberit HDPE Sovent fittings prevent a hydraulic blockage from forming in the stack. Because the stack flow is guided around the point of connection, the incoming waste water has time to switch to the vertical direction so that it flows in a parallel direction when it meets the waste water in the stack flow.
This minimises the collision turbulences of the two waste water flows and therefore reduces the pressure fluctuations in the system. Guiding the stack flow around the point of connection also causes the flow velocity to decrease which limits the kinetic pressure. In addition, the partition in the Geberit HDPE Sovent fittings prevents foam, dirt particles or splash water from getting into the branch discharge pipe.
The hydraulically optimised d110 Geberit Sovent offers discharge capacity of 12 litres per second and dimensions of d110 with ventilation in the event of a change in direction and 0–5% slope in the case of a horizontal pipe layout.
A conventional discharge pipe on the other hand with pipe dimensions of d160 and additional d90 ventilation pipe has a discharge capacity of 12.4 litres per second and 0–5% slope in the case of horizontal pipelines.
Geberit HDPE BottomTurn bend and Geberit HDPE BackFlip bend can be used only in conjunction with the Geberit HDPE Sovent fitting d110 and the drainage systems Geberit HDPE or Geberit Silent-db20.
Furthermore, Geberit HDPE Sovent Fittings and bends with SuperTube technology also stand out due to their patented, flow-optimised design. Nassar says: “The flow-optimised design in the Geberit HDPE Sovent fitting d110 comprises a flow divider and a swirl zone. The flow divider adjusts the flow of the water and supports functional stability in the system. The swirl zone creates a rotating movement that allows the water to flow along the pipe wall, which produces a continuous column of air. This effect increases the discharge rate of the fitting by more than 30% (from 8.7-12 litres per second).”
The Geberit SuperTube drainage system will be available at leading suppliers in the Gulf Region from 1 April 2019. “We have a demonstration module installed in our Dubai Training centre and we will be conducting training on the system and demonstrating this new innovative system to MEP professionals in the region.”
Growth and trend
Talking about the firm’s presence and growth in the Middle East, Nassar says: “Geberit has had a presence in the Gulf region since the 1970’s. In those days we brought our goods in straight from Europe. Now Geberit generates sales in around 120 countries worldwide and has a presence in around 50 countries. Our Gulf regional office was opened in 2000 and is now based in Dubai design district, we partner with a network of leading distributors across the region. Our goal at Geberit is to be a perfect partner in the market. We offer a personal project service for planning and implementation with training in our training centre or directly at a site. As a system provider Geberit is well placed, we have a comprehensive product range consisting of the entire sanitary technology behind the wall–concealed cisterns, installation systems and piping systems as well as a complete range of products in front of the wall-bathroom series with their ceramic sanitary appliances and bathroom furniture. Our products are used in new buildings as well as renovations and modernisation projects.”
Talking about the trend in piping systems in the past few years, Nassar says that the people are moving from PVC to HDPE. He adds: “Geberit HDPE welding joints ensure 100% tightness and provide a completely leak-proof system. The good characteristics of Geberit HDPE offer an easy way to prefabricate pipe assemblies. Complicated labour at the site is eliminated by prefabricated pipe assembly and the clean and easy organised work at the workshop again saving time. Geberit HDPE is ideal for use in industrial and laboratory installations. The material covers various application fields. There is no need to change the pipe material. Being resistant to extreme temperature, Geberit HDPE can be safely used as waste pipe with no mechanical load, up to 80°C. Temperatures of up to 100°C for short periods (e.g. surges of steam) are permissible. HPDE can stretch elastically and resume its original shape, remaining completely intact and undamaged in temperature extremes.”