Traditional elevator construction takes time and money. They are often the longest critical path. For low-rise buildings where improved accessibility is paramount, the continuing development of modular elevator technology is providing significant benefits.
Installation of a traditional elevator can be tedious. "Stick-built" elevators first require a pit to be built and a hoistway constructed, either from wood, steel or concrete block. Elevator components are then brought on-site and assembled in the hoistway.
A modular elevator is a standard commercial elevator installed into a prefabricated structural steel hoistway. The welded steel hoistway structure fully contains the elevator car, rails, controls, and drive system inside. It is sheathed with materials to meet the building requirements. The modular elevator is then trucked to site and lifted by crane and set into place in the elevator pit. Once installed, it functions exactly like a stick-built elevator, and is serviced the same way.
Stick-built elevators generally take about three weeks to assemble on-site, and this does not include the time it takes to build the hoistway. Lead-in times, in addition, can be as long as five to six months. Resolving the relationship between the elevator and the hoistway, and the hoistway and the pit, to ensure all required codes and approvals are obtained can hold up progress.
To mitigate these delays and breeze through the check process, some conventional elevators have been over-designed. Speed of approval is thus offset by higher system prices.
Installation of modular elevators, which arrive on-site completely assembled, can take just three days. In addition, with the system and structure is already engineered, the design process all but disappears upfront. Engineering time and expense can be avoided with systems ready for installation in as little as eight weeks.
“It’s just a matter of making the hookup and adjusting it. You eliminate many of the trades necessary on-site, hence the simplicity,” said Tom Shield, president and founder of Modular Elevator Manufacturing. “You’re not dealing with the challenge of your hoistway being off by two inches.”
Conventional elevator hoistways, constructed from cinder block, require much greater support. Heavy structures potentially require grade beams and/or caissons, increasing costs and build time.
Most modular elevator systems are self-supporting. The use of tubular structural steel means a lighter structure, which means smaller concrete pits. Not needing to rely on building structure for support also makes them an excellent choice for retrofit projects.
The old way of building an elevator is to build the shaft on a job site vertically, then assemble the numerous components inside the vertical shaft in less than optimal conditions. This dated method requires more time to build and is less safe.
Modular elevators are built under controlled factory conditions to meet strict quality and tolerance standards. This also eliminates the safety issues involved with erecting scaffolding and working outside subject to wind and other elements.
There are also various alternative technologies to choose from which provide additional benefits to more traditional elevator systems including elevators hoisted by a hole-less hydraulic lift, in-ground jacks, or machine-room-less (MRL) technology.
The mechanisms that moves an MRL elevator car reside at the top of the shaft or hoistway instead of in a separate room located in the building. This is possible because the machine is smaller and more efficient than in a traditional traction elevator design.
Studies have found that MRL elevators consume less energy than traction elevators and they do not use hydraulic oil that can spill or leak. A study from VTT's Technical Research Centre concluded that an MRL can consume approximately half the energy of a traction elevator and about one-third of the energy of typical hydraulic machine.
Although designed to be a permanent part of a building, modular elevators can also be relocated.
“We know of one customer that used their modular elevator for two years in a temporary building while a more permanent structure was under construction. They then moved to the new building and sold their elevator. Another customer used their modular to provide underground construction access while remodeling subway stations and relocated it as needed to rebuild multiple stations,” said a spokesman for Phoenix Modular Elevators.
On a micro-level, some elevator manufacturers are moving away from a largely customized process and also offering standardised versions of key components. Parts such as the power converter, rails, and cab can be mixed and matched to suit the building’s needs. A library of cab colours and textures further simplifies the process.
There are a number of key questions to consider though before deciding on the appropriateness of the ideal modular elevator depending on the unique characteristics of the site and the building.
On what side of the building will the elevator be housed? If a modular elevator appeals, will the free-standing hoistway add to or detract from the building’s appearance?
Does your site have crane access? If not, modular elevator costs can escalate.
Are you in an areas with high levels of seismic activity? If so a free-standing structure for modular elevators must be located a short distance away from each other to keep the structures from colliding during seismic events.
After asking these questions, you can determine whether your low-rise building may be ready to benefit from modular elevator technology.