As increasing numbers of people work and live in city centres, the lack of space available for residential developments means that high-rise buildings are becoming more widespread.
When installing drainage and ventilation pipework in high-rise buildings, traditional design standards dictate that a secondary ventilation stack has to be used to overcome air pressure changes. This is to account for the positive and negative air fluctuations that can compromise water trap seals due to the unsteady flow of water through the pipework. Incorrect air balance can result in blowback and siphoning of the water seal in the trap, which could pose a public health risk.
To maintain stability in a drainage system, it is necessary to alleviate this change in air pressure immediately. This response time is paramount for protecting water trap seals, with traditional secondary pipework systems thought to be the only way to provide this function.