03 Jul 2019

Water Pressure In Tall Buildings: Challenges

Water pressure control is critical to prevent catastrophic pipe failures that can result in water leakage - and all the associated costs from the ensuing damage. But when it comes to tall buildings, engineers are presented with a number of unique challenges in ensuring that pipework and controls are effective in maintaining the integrity of the entire system.

Over a series of four blogs, we will discuss how plumbing and heating professionals working in multi-storey buildings can help to deliver an effective water pressure management system that protects and maintains public safety.  

We will cover occupancy and engineering challenges, such as noise control and surge protection, and the different types of pressure control valves for different applications, along with the importance of sizing and positioning in order to avoid noise and poor performance.

First up, let’s take a look at the specific challenges involved in specifying and designing water controls for tall buildings.

In order to address the question of how to manage water pressure control in a tall building, we need to understand how the building differs from an ordinary ‘large commercial’ building and what effect this has on the specification of potable water controls.

Typically defined as a height of 10 storeys and above, with each story being three to four metres, tall buildings normally include boosters that have an outlet pressure of five bars or more. The ideal water usage pressure for a residential or light commercial building is one to three bars. If the water pressure is less than one bar, there may not be enough pressure to shower, and if it is over three bars, water may be wasted.

Pressure regulation is necessary in tall buildings to ensure a constant and appropriate ideal water pressure at each outlet on every level.  The water system in a tall building is usually fed at a high pressure by a booster set, to ensure delivery to the top floor at adequate pressure.

However, without regulation, the pressure would be higher on each floor, from the top downwards. This is a problem because these pressures might cause damage to pipework and would be far too high for washbasins, sinks, toilets, laundry and kitchen equipment. Leaks are more likely to occur, appliances will not operate correctly and the system noise will be much higher, causing disruption to occupiers.

Another key consideration is the need to ensure that buildings are fully compliant and that manufacturer equipment is capable of operating to high system pressure regimes. The relevant regulations and standards cover pressure and surge control in large buildings, and these are BS806 Part 2 – Design (2005), BS 8558 2015 and Building Regulations Part G.

Consideration also needs to be given to the zoning of a building. Does it have one life or multiple stage lifts? The client will often dislike mid-building plant rooms because this is prime selling space for extra apartments or living spaces. System noise control is also particularly important. The key factor here is the choice of control equipment must be robust and fit for purpose to ensure that noise is controlled.

Many of the problems with sudden over pressure of boosted water systems develop within the filling stage of the system. How do we ensure that the system is filled safely, and without sudden over pressures and how to ensure that air evacuation and air inlet is controlled at the top of the risers?

Check back in on the next three blogs in this series as we address these issues in more detail….