As high-rise buildings are becoming a more prevalent sight on UK horizons, it is important to recognise the additional challenges that engineers face as buildings get taller
Supplying sufficient water pressure to all floors within high-rise buildings has always been a challenge in which engineers have had to overcome through careful design. The design should aim to maintain an even distribution of water to all floors, as well as combatting the effect of gravity and ensuring the higher floors still receive adequate water pressure.
Due to the sheer height of many high-rise buildings, it is common that the municipal water supply pressure will not be adequate to meet the needs of the building; these buildings will often require a pressure-boosting system, this would typically be in the form of booster pump sets or elevated storage tanks. Without a pressure-boosting system, the higher floors within the system may receive low water pressure and during peak times all occupants may experience this issue.
Pressure-boosting systems will increase the pressure of the water to a level that will ensure all floors within the high-rise receive water at an adequate pressure, even during times of high demand. However, whilst solving one problem, pressure-boosting systems, and the subsequent high pressure, can create further issues.
The increased pressure rating often means that standard rated pipes, valves, pumps, and fittings may not be sufficient. Careful design will ensure that the right products are specified from the beginning, therefore reducing wastage and time. Since the introduction of BIM into the building services industry, it has become easier to flag potential issues at the very early stages, especially in relation to sizing and flow, thus ensuring all of the products are compatible before the installation stage.
If parts are installed that are not capable of operating at such a high pressure, the water pressure may cause damage to the pipes, valves and fittings and potentially cause leaks.
With good planning and careful consideration, the issues surrounding excessive pressure are usually relatively easy to resolve through the use of high-pressure products and Pressure Reducing Valves (PRV’s) in the system.
PRV’s are designed to restrict pressure; as water moves from the inlet port, it must pass through a spring and a diaphragm which will cause resistance and therefore lower the pressure to the desired level as the water leaves the valve through the outlet port.
The advantage of a pressure reducing valve is that they are set to regulate the water flow to a specific pressure. That means if there is a sudden spike in pressure, the spring and diaphragm in the valve will tighten, thus maintaining a consistent and safe water supply pressure, protecting the equipment throughout the system.
It is essential that PRV’s are installed in high rise buildings to assist with maintaining this consistent water pressure, due to the height of the buildings, and the need to supplement the municipal water supply to create good water pressure on the higher floors, without the introduction of PRV’s this could cause severe issues on the lower floors with regards to over pressure and water delivery.
Systems may also experience issues if the municipal water supply is cut off or if the pressure boosting systems fail; whilst this will be infrequent, it is important to protect the system from back flow should this situation occur. The system can be protected through the use of non-return valves; these valves will prevent the force of gravity from taking the water back downstream and potentially causing damage to the pumps and other equipment.
PRV’s are usually used on the legs coming off the main riser, only reducing the pressure when the water has reached the desired level. Meaning that the core section of the system – the riser and plant rooms – are subjected to much higher pressures and therefore valves installed within these sections must be able to withstand a much higher-pressure level. This applies to all types of valves on the core sections, such as, isolation, commissioning, check, and strainers. These valves are essential for the smooth operation of the system and to enable maintenance to take place.
Albion will be launching a full range of PN25 valves, that will be held ex-stock and available for next-day delivery.
Albion’s PN25 range includes butterfly valves, non-return valves, strainers, a double regulating valve and an orifice plate. For more information contact our sales team on firstname.lastname@example.org or call on 01226 729900.