????允許部分上班族在緊急情況下使用電梯。按照慣例，在緊急情況下，高層建筑的電梯僅供消防人員使用。NIST建議，建筑電梯應能夠承受火災和混凝土芯結構受損。

????使用黑暗中可發光的標志指示樓梯間與緊急出口。聽起來很簡單，但并非所有建筑都有這樣的標記，尤其是在2000年之前建造的建筑。911事件的悲劇發生5年后，紐約市規定在樓梯間設置發光標識，紐約因此成為第一個有類似規定的大城市。目前，超過1,500棟建筑設置了類似標志，但這在美國的高層建筑中僅占一小部分。

????如果一個城市采用了這些建議，并且要求高層建筑設置避難層、視頻監控和自動灑水系統，摩天大樓的安全性將大幅提高。

????此外，放寬對直升機停機坪的要求，也可以使建筑師們設計出更有趣的屋頂天臺。直升機停機坪至少需要50x50英尺的空間，而且周圍通常要設立25英尺的緩沖區。這導致各種大同小異、四四方方的屋頂，占據了洛杉磯的天際線。

????除了有失美感外，設有直升機停機坪的四方屋頂，也錯過了利用可持續功能創建“綠色”屋頂的機會。現在，洛杉磯的大樓也可以像上海的上海中心大廈（Shanghai Tower）一樣，在屋頂設計可以收集雨水的螺旋形結構。部分摩天大樓的屋頂設計了風力渦輪機，用來風力發電，例如倫敦的斯特拉塔（Strata Tower）。

????對于放寬摩天大樓樓頂直升機停機坪的規定，我們無須擔心，恰恰相反，這將給我們帶來許多好處。洛杉磯人會設計出哪些有創意的摩天大樓呢？我很期待。

????本為作者海爾?阿爾孔德曼尼是伊利諾伊大學芝加哥分校（University of Illinois at Chicago）城市規劃與政策系教授。本文原刊登于信息交流網站Zocalo Public Square。（財富中文網）

????譯者：劉進龍/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.