Elevator Science 101

Elevator Science 101

When was the last time you were standing in an elevator lobby and thought to yourself, “Wow, whoever designed this elevator system did a really good job”? Yeah, right, huuh? Bet you didn’t even know that there is a whole science devoted to vertical transportation, did you? Most think the architect just plots some elevator shafts in the building plans and then the elevator contractor fills in the hole. This couldn’t be further from the truth.

When designing a building, an architect is given certain design criteria by the developer. That criteria includes projected population and projected population density, meaning total population and population per floor, among many other things. Now, architects are very smart people, but that doesn’t mean they know everything about building a building. This is where consultants and consulting engineers come in. Did I mention that architects are smart? That’s why they defer to experts in individual disciplines.

The information an architect provides to an elevator consultant varies. Often, the consultant will have to make assumptions based on square feet per floor and the number of floors the architect has planned. This is not preferred, but you work with what you have. Ultimately, the consultant prefers to have the total projected population, population per floor, square feet per floor and total occupied floors. Given this criteria, it is up to the consulting engineer to get 90% all of these people in an elevator in 30 seconds or less during the highest of up peaks, typically in the morning.

You may be thinking, that’s no big deal, just install a lot of elevators. It would be nice if it were that easy. An elevator consulting engineer has to be able to optimize the amount of elevators while minimizing their foot print and energy consumption. This writer is going to assume that people reading this article are building owners or managers and understand the importance of leasable space and energy efficiency.

An elevator can have many capacities, speeds, door opening sizes, door speeds, to name a few of the most common mechanical restraints. Along with the mechanical restraints, there physical restraints. How many people will crowd into an elevator? This varies widely by region. How fast an elevator reaches it’s acceleration and deceleration profile or “Jerk” is very important. These are important because if people do not feel comfortable in an elevator, it doesn’t matter how fast they get to their floor, if they don’t feel comfortable in the elevator, they are starting their day with a bad experience. Nobody wants that. The consultant also has to take ADA requirements into account.

Using this information, the consultant can provide the architect with how many elevators they need, how many rises are required, the capacity of each elevator, what speeds they need and the opening sizes needed for proper throughput.

So there you go. Now you know more than the consultant who comes to your building and tells you that your maintenance provider isn’t performing because your car tops and pits are dirty.

If you are interested in more detail of how buildings are “Elevatored”, we recommend reading the Elevator Traffic Handbook: Theory and Practice by Dr. Gina Barney and Lutfi Al Sharif. This writer had the privilege of calling Dr. Barney an associate many years ago and can personally vouch for her credibility. For this writer, it’s kind of like being able to say, you used to work with Albert Einstein.

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