如何让摩天大楼更安全？

    允许部分上班族在紧急情况下使用电梯。按照惯例，在紧急情况下，高层建筑的电梯仅供消防人员使用。NIST建议，建筑电梯应能够承受火灾和混凝土芯结构受损。

    使用黑暗中可发光的标志指示楼梯间与紧急出口。听起来很简单，但并非所有建筑都有这样的标记，尤其是在2000年之前建造的建筑。911事件的悲剧发生5年后，纽约市规定在楼梯间设置发光标识，纽约因此成为第一个有类似规定的大城市。目前，超过1,500栋建筑设置了类似标志，但这在美国的高层建筑中仅占一小部分。

    如果一个城市采用了这些建议，并且要求高层建筑设置避难层、视频监控和自动洒水系统，摩天大楼的安全性将大幅提高。

    此外，放宽对直升机停机坪的要求，也可以使建筑师们设计出更有趣的屋顶天台。直升机停机坪至少需要50x50英尺的空间，而且周围通常要设立25英尺的缓冲区。这导致各种大同小异、四四方方的屋顶，占据了洛杉矶的天际线。

    除了有失美感外，设有直升机停机坪的四方屋顶，也错过了利用可持续功能创建“绿色”屋顶的机会。现在，洛杉矶的大楼也可以像上海的上海中心大厦（Shanghai Tower）一样，在屋顶设计可以收集雨水的螺旋形结构。部分摩天大楼的屋顶设计了风力涡轮机，用来风力发电，例如伦敦的斯特拉塔（Strata Tower）。

    对于放宽摩天大楼楼顶直升机停机坪的规定，我们无须担心，恰恰相反，这将给我们带来许多好处。洛杉矶人会设计出哪些有创意的摩天大楼呢？我很期待。

    本为作者海尔•阿尔孔德曼尼是伊利诺伊大学芝加哥分校（University of Illinois at Chicago）城市规划与政策系教授。本文原刊登于信息交流网站Zocalo Public Square。（财富中文网）

    译者：刘进龙/汪皓

    Allow some office workers to use elevators in an emergency. Conventionally, in an emergency situation, elevators in high-rise buildings are used by firefighters only. NIST recommends building elevators that can withstand fires and structural damage in the concrete core of a building.

    Mark stairwells and exits with glow-in-the-dark signs. As simple as it sounds, not every building has such markings, especially those built before the 2000s. New York was the first large city to require luminous markings in stairwells, five years after the 9/11 tragic events. More than 1,500 buildings now have the markings, but that’s still a small fraction of America’s tall buildings.

    If a city adopts these recommendations – and also asks tall buildings to include refuge floors, video-camera surveillance, and automatic sprinkler systems — the safety of the skyscrapers will increase significantly.

    Relaxing the requirements of a helipad also will empower architects to create more interesting rooftops. A space 50-by-50-feet wide at minimum is required for a helipad spot, plus a typical additional 25 feet around it as a buffer. This has resulted in a repetitive, boxy roof shape in the Los Angeles skyline.

    Beyond aesthetics, boxy rooftops with helipads are really a missed opportunity to create “green” roofs with sustainable features. Now Los Angeles can do something like the spiral form in the rooftop of Shanghai Tower in Shanghai that captures rainwater. Some towers’ tops are now designated for wind turbines to harness wind energy, such as the Strata Tower in London.

    There’s nothing to fear – and much to gain – in relaxing the helipad requirement. I, for one, will be watching to see what inventive skyscrapers Angelinos come up with.

    Kheir Al-Kodmany is a professor in the Department of Urban Planning and Policy at the University of Illinois at Chicago. He wrote this for Zocalo Public Square.