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Do "Close Door" buttons in elevators work?

📓 The short answer

It depends. If you're in the United States, probably not as you would expect them to work. If you're outside the U.S., probably so.

📚 The long answer

As with many curious questions, this one's answer starts with, "It depends."

It depends how old the elevator is, how that particular elevator was programmed, and what country the elevator is in. Let's start with the U.S.

Here's a breakdown of likely situations of when the "Close Door" button will and will not function in the U.S.:

❌ Won't function: The elevator was manufactured after 1990, and it's been less than three seconds since the door opened.

This is the most common reason that "Close Door" buttons are perceived to be ineffectual. In 1990, the Americans with Disabilities Act (ADA) was passed and it included specific requirements to have elevator doors stay open long enough for people with disabilities to get on and off.

Specifically the regulation states, "User activation of door close (or automatic operation) cannot reduce the initial opening time of doors (3 seconds minimum) or the minimum door signal timing." Minimum door signal timing refers to a set amount of time based on the distance between the elevator call buttons and the elevator calculated by 1.5 seconds per foot of distance.

The law applies to elevators built after 1990, and since the lifespan of an elevator is about 25 years, most elevators today need to adhere to this three-second minimum. So if you press the "Close Door" button immediately, it won't work.

❌ Won't function: The button is broken or was programmed to have a long delay.

If the "Close Door" button breaks, it obviously won't function. And because there's already a delay, it's a hard problem to diagnose. Additionally some buildings program their elevators to have even longer delays. For example, this longer delay is common in hospitals where it takes time for beds to be rolled through the doors.

✅ Will function: It's been more than three seconds.

My research suggests that if you wait longer than three seconds and then press the "Close Door" button, it should respond fairly quickly. I emphasize "fairly" here because the elevator may have an additional delay from the moment you press the button to the moment the door actually starts to close.

✅ Will function: You are a firefighter or other emergency responder and you have a key to put the elevator into "Fire Service Mode."

The internet is littered with articles claiming that 80% of "Close Door" buttons in the U.S. don't work, based on a single quote from a Radiolab interview. However, it's hard to believe this is the case when emergency personnel need to be able to use this button to operate the elevators in high stakes situations. The "Close Door" button should work when you have the key to put the elevator into "Fire Service Mode."

✅ Will function: You have a key to put the elevator into "Independent Service Mode."

Elevators also have a setting called "Independent Service Mode," often used by movers to ignore any other calls and have the elevator act as your personal lift. In most cases, the "Close Door" button should work in this mode.

✅ Will function: You are in a freight elevator.

Freight elevators are not required to adhere to ADA guidelines, so there is no three-second minimum window to prevent the "Close Door" button from working.

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Now if you're outside of the U.S., the ADA does not apply to your elevators, so you have a better shot at closing the door before your foe enters.

There's not a comprehensive resource showing which countries have functional "Close Door" buttons, but here are a few countries' elevator settings I was able to find on a case-by-case basis:

• According to The Telegraph, "Close Door" buttons work properly in the United Kingdom.
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• Japan's elevators also have fully functional buttons, according to Reddit.
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• Australia may or may not have a built in delay for the button to work, according to the same Reddit thread, but I was not able to find corroborating evidence to confirm or deny.

​Sources for this week's newsletter​

📖 Book of the week

​The Woman Behind the New Deal: The Life and Legacy of Frances Perkins by Kirstin Downey​

Frances Perkins is not a household name but she should be.

The first woman to serve in a presidential Cabinet, Franklin D. Roosevelt's Secretary of Labor was a tireless advocate for the working class and is credited with helping to create Social Security, unemployment insurance, and the minimum wage. Her personal life story and tenacity in fighting for the working class is astounding. I'll admit this book is dense at times with all the interesting details of Perkins' life, but it's well worth a read if just to really appreciate the protections and social safety nets we take for granted today in America.

👀 Catch up on other curious questions

• ​How does dry cleaning work?​​
• ​Why are skyscrapers constructed with so much glass?​​
• ​How do court reporters type so fast?​​

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