前室加压防烟楼梯间的高度上限

解释了加压楼梯间於冬季时其压力的变化可为负、或为正压．顶层及二层楼梯门会承受最大的压差，令楼梯间高度受较大的限制。提出了楼梯间不加压（设同风量均匀送风及均匀排风），只设前室加压，同时楼梯间最上部及最下部设自动对外开口的方案。它能容许更大的高度及较小的负压值。

Maximum height limit of staircase with vestibules pressurisation

Pressure profile of staircase in winter is explained that it can be negative or positive. Staircase doors at the top floor and the first floor will receive the highest pressure which limits the height of a pressurized staircase. It is suggested not to pressurise the staircase （with equal outdoor air supply and exhaust） but the vestibules only, and to install automatic vents at the staircase top and bottom locations. This can. allow a higher height and a smaller negative pressure.