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We've all hopped into an elevator, and those of us who are high-rise dwellers or downtown office workers use them on a regular basis. What you might not be familiar with, though, is both that there have been huge advances in elevator technology in recent years, and that they are not strictly a modern invention. Evidence of the very first elevator was recorded around 236 BC, designed by Archimedes of Syracuse – a Greek mathematician, physicist, engineer, astronomer, and inventor from the ancient city of Syracuse in Sicily.
Despite this, the earliest elevators for which evidence still exists are that of the Roman Colosseum completed in AD 80 – where 28 elevators were used to transport animals up to the floor. These elevators could carry up to 600 pounds, and needed up to a crew of eight to operate them. One such Colosseum elevator was recently recreated onsite for a documentary, and was left in place to show tourists to Rome how it used to operate.
Elevators have obviously evolved since then, with many different types in use today. A common modern-day elevator consists of a cab mounted on a platform that sits within an enclosed shaft. In a traction elevator, cars are pulled up by means of rolling steel ropes over a grooved pulley, with the weight of the car balanced by a counterweight. Hydraulic elevators use the principles of hydraulics to pressurize a piston which raises or lowers the car. Roped hydraulics use a combination of both ropes and hydraulic power to raise and lower cars.
The technology used in elevators depends on many factors. Hydraulic elevators are cheaper, but installing cylinders greater than a certain length becomes impractical for high lift distances – such as in high-rise towers. For buildings that are taller than seven floors therefore, traction elevators are used, another benefit of which is that traction elevators are faster than hydraulic elevators.
Increasingly taller buildings have demanded increasingly complex elevator systems in order to make travel a more seamless experience for the many riders that they have. Some office towers employ double-decker elevators — traction elevators with an upper and lower deck which can serve two floors at the same time — which are driven by the same motor. The system increases efficiency, and saves space so additional shafts and cars are not required. You can see double decker elevators at work at Scotia Plaza, in Downtown Toronto.
Another recent innovation is the destination dispatch system – an optimization technique which has passengers heading to the same group of floors share an elevator, thereby reducing waiting and travel times. It works by passengers requesting a particular floor using a keypad, touch screen, or keyfob in the lobby, and then being directed to the appropriate car.
In Ontario, accessibility laws state that elevators must be provided between all floors in most new buildings including assembly buildings (theatres, community centres, places of worship), care buildings (long-term care homes), and commercial/retail buildings (supermarkets and shops).
In the Ontario Fire Code, buildings greater than six storeys with residential occupancies are required to have at least one elevator provided, which is identified on the street floor, for use by firefighters. As towers grow taller than six storeys, more than a single elevator is often necessary.
Large buildings certainly need more than one elevator though, so what dictates how many elevators are necessary in a particular building?
There are many factors that play into the number of elevators employed in a building. The use of a building — residential, retail, hotel, office, etc. — will affect the travel demands. The number of levels and capacity of each level for residents, patrons, or employees, will create greater or lesser demand. The size of elevators is a factor too; how many people can each carry? Often, one or more elevators in a building will be built with more space and higher carrying capacity so that heavy or irregularly shaped items can be transported by elevator during move-ins or move-outs.
While there are no standards in Ontario requiring a particular number of elevators per residential unit, a generally accepted target for elevator to unit ratio is one elevator for each 100 units in a high-rise residential tower (although some jurisdictions have a general recommendation of one elevator per 90 residential units). Boutique luxury residential buildings tend to have more elevators, one for every 60 units for example.
Recent condo proposals in Toronto have been increasing the number of units per elevator, such as at 145 Wellington West which we recently wrote about that proposes four elevators for its 512 suites, or one elevator to 128 units, while another proposal at 123 Edward Street that we also covered recently has ratio of a one elevator to 260-unit ratio for its first tower, and a one elevator to 370-unit ratio for its second tower. We have never seen numbers like those 123 Edward ones before, and do not expect that proposal to be approved as currently planned, but it begs the question whether Ontario should regulate the number of elevators per unit.
With more frequent traffic in hotels, the rule of thumb in the hospitality industry seems to be one elevator for every 75 to 80 hotel rooms. It is also encouraged that the farthest room not be located more than 150 feet from the elevators.
With people packed more tightly in office towers than in residential ones, one elevator is recommended for approximately each 50,000 ft² in area, as well as an additional elevator for every two and a half floors. This means in a 100,000 ft² commercial building that is five storeys tall, there should be at least three elevators. In the case of commercial buildings over 16 storeys, it is recommended that elevator should be employed in banks, or groups, and that no more than eight elevators should be grouped in a single bank.
At the end of the day, with no hard set rule about the number of elevators necessary in a large residential building in Ontario and proposals beginning to exceed typical elevator to unit ratios, it is possible that some new rules could be needed.
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