Designers are putting bigger demands on lifts. The vertical transportation industry is called upon to get greater numbers of people where they want to go quicker and more efficiently. Richard Stirling talks to Arup director Julian Olley about how the industry is taking the strain.

NOBODY likes to stand in a crowded stuffy lift. It doesn’t matter if we choose to work in high-rise office blocks, or move to in modern city centre apartments, we still like a bit of room to move around in. But as designers look to create greater efficiencies in their use of space, things are getting positively overcrowded.

Designers face two big problems when thinking of ways to move people between floors in their buildings. The traditional lift technology is not enough to get people to where they want to go quickly enough, and refurbished buildings often have to cope with greater numbers of people than they were originally designed for.

Arup director responsible for the vertical transportation group, Julian Olley, says designers and contractors are using different technologies to meet the greater demands, and he says hall call allocation is becoming a more popular method to transport greater numbers of people.

Lift capacities on the rise

Hall call allocation features the control buttons on the landing, as opposed to inside the lift car itself. Passengers key in their destination in advance, which allows lifts to take them where they want in the most efficient ways. Groups of passengers travelling to one floor will be directed to one particular lift, instead of two lifts having to stop at the same floor.

“The system has been used quite a lot in refurbishment because it improves the lift capacity and avoids the lifts stopping all over the place,” says Olley. “Normally, you might get 15 people stopping at 10 different floors, which  is annoying for people working at the top floors of tall buildings.

“Because each lift is making fewer stops, they can carry more people. This can be used for refurbished buildings, which were built for fewer people and now suffer under-capacity. In new developments it means fewer lifts.”

Hall call lifts are currently being planned for some of London’s planned skyscrapers, which include the external lifts in Richard Rogers’ 122 Leadenhall Street tower. Hall call has been retrofitted in the 12-storey 1 London Wall. The building was originally designed for general occupancy but its lifts have struggled as the number of people occupying the building has increased.  Arup is currently looking at using hall call for projects with Stanhope in London and Croydon.

Hall call systems have been conspicuous by their absence in the UK, Olley explains, because they have not enjoyed the best reputation with architects, who have been shy of using them. “They haven’t been used extensively to-date,” explains Olley. “Most designers of tall buildings are considering it at the moment. Because the first uses were for refurbishment, it got a bit of a bad name. People saw it as a sticking plaster for buildings that were designed without the lift capacity for their occupants, instead of seeing the benefits.”

Planning ahead

Olley says hall call will play an integral role in new space-saving lifts. Twin deck lifts use two lift cars in the same shaft. They are a natural progression from double deck lifts, which take the form of two lift cars built
together on a single rope, so they move up and down the shaft in tandem.

“Double decks have been used pretty extensively internationally for high buildings,” says Olley. “Most of the recent half dozen or so tall buildings proposed for London have double decks because they take up much less space in the building.”

The biggest hurdle to using double decks in the UK has been that there are few buildings tall enough to accommodate them, Olley adds. “If you look at the Far East and places like Hong Kong they are extensively used because they have got a lot of buildings that are 80 or 100 stories high, whereas we don’t tend to construct buildings that tall,” he says.

Twin wins

Using double decks allows designers 1.8 times the space of conventional lifts, explains Olley, but cost more than twice as much. They also tend to be bespoke products, and lack the repeatability in design of twin lifts.

“With twin decks, most of the drivers are standard, and they share rails and doors,” Olley explains. “They tend to have some clever electronics attached, bit you’re not putting anything expensive in to make the two lifts operate in the same shaft.”

Another drawback of double decks is that they can sometimes be difficult to use. “One of the biggest perceived problems with double decks is they have to stop when the lift above does,” says Olley. “Most users wouldn’t know they were in a twin lift. You just get into a lift car and go to whichever floor you want.”

Having two lift cars rattling round in the same lift shaft might sound to some people a recipe for disaster. However, the lifts are protected through electronic and mechanical means. The lift’s hall call mechanism will plan where each lift goes and sensors on each car will tell each where the other is in the shaft and how fast it is travelling.

Should these fail, the cars get involved in a kind of “vertical jousting”: One car has a long pole on the top and the other on the underneath, and in the event of the electronic protection failing, each pole pokes into a spigot, which slams on the brakes. Opening up new possibilities The benefits of hall call systems go beyond the handling capacities of lifts and coordinating how they travel in the shaft. Hall call can help people make better use of the buildings in which they live and work.

The hall call mechanism can have a disability button to give people greater access and generally make their lives easier. When the lift arrives, the system will know when a wheelchair user has called the lift so it won’t put a lot of people in with them. It could also have features such as keeping the doors open for longer to let people with mobility problems use the lift more comfortably.

Hall call is also being linked to security systems and turnstiles in buildings. Once a person has swiped themselves through the turnstile the system will automatically know which floor they work on and will take them to that particular floor. This could also be used to stop people going to floors they aren’t allowed on.

Whether designers are accommodating more people into buildings, or making life better for the people already using them, it looks like they will soon revolutionise the way we travel between floors. Olley says the construction industry will embrace hall call mechanisms as the norm. “People have shied away from them for a while,” he says. “Our view is it will become standard in five to ten years’ time.”

Lifts are already the safest form of transport in the world with far fewer casualties than planes, trains or cars. With innovations such as hall call and twin decks, they will soon be recognised the world’s most efficient transport.