(Published in AJFocus)

While Architects have to balance aesthetic and urban considerations with the client's requirements prior to detail design, the lift and escalator consultant has a different set of priorities. As part of a team we are fundamentally dealing with a number of more basic building related issues simultaneously. Our primary function is collectively making the building-investment economics stand up. With too few lifts and escalators, the circulation fails and the rental levels suffer; too many lifts and we take too much space and, yes, the rental income will drop as a result.

Of course, equally important is the focus and management of the thousands of people and visitors to the building in question. Essentially, lifts and escalators form natural lines of communication, ensuring that the building ticks harmoniously through its existence. Once these fundamentals are set, the detail design can begin.

Up to Standard

The present British Standard for lifts is known as BSEN 81. Part 1 for traction equipment and part 2 for hydraulic equipment. And the modernisation of lifts is still carried out under BS 5655 part 11 for traction lifts, however this standard is about to be superseded.

Requirements for Fire-fighting lifts are encompassed in the British Standard BS 5588. The principle criteria for the provision of lifts are: over 18m travel above ground floor, over 9.5m travel to basements or a single area 900m square at any level above ground. There should be a minimum of one eight-person 630-Kg capacity with Class O finishes within a travel distance of 30m-40m from each other depending on the route for hose reels.

Traffic guidance

Waiting time is a function of the 'system interval'; these terms are often confused. Interval times should not exceed 30 seconds. The amount of passenger traffic transported is described as 'handling capacity' and measured as a percentage over five minutes.

British Standards advise that, for a multi-let property, a lift system should handle 12% of the building population above the main floor in five minutes. Significantly it also states that for a single-let property, the lifts should move 17% of the population over the same period. However the British Council of offices (BCO) does not make this differentiation and advises 15% handling capacity whatever the nature of the tenancy.

It is easy to fall into the trap of considering that a multi-let property is simply a building with more than one tenant. Whereas in fact if a collection of the tenants occupy more than two floors and represent a significant critical mass or a 'head office' function, it is reasonable to assume that there will be inter-floor traffic. Lift traffic, in turn, increases demands on the system and service expectations. This then becomes a special case.

For 'tall' buildings a slightly different methodology applies, but this is perhaps a subject for another occasion.

In summary, the entire subject of lift traffic hinges on the perceived density of occupation. Architects can often be wise before the event and opt for a lightly populated space. The BCO follows suit and considers 14m square per person as a base line whereas 10-12m square per person would be a wiser choice. Visit www.dunbarboardman.com for further information on the subject.

Keeping in step

Staircases can provide a useful function in the planning process for vertical transportation. They should be accessible in their location and will divert traffic away for the lift cores. Attractive processional staircases can have a life of their own, in terms of design and function.

In short the quality of staircases and their accessibility can draw high levels of traffic which can avert expenditure for the provision of additional lifts. Since lifts travel though the building, the use of staircases at lower levels increases the net lettable office space at higher floors.

Standard Lift Equipment

Loved by Quantity Surveyors and tolerated by Architects, standard lifts do have a purpose as they provide cost-effective solutions for most buildings. However, the designer must adhere to the sizes stated in the manufacturer's documentation.

As a general rule, lift companies often show the minimum size that they can work within, which often conflicts with their competitors. This practice can then restrict the tendering process at a later stage

Secondary lift systems, such as fire fighting lifts, goods lifts and disabled access systems can all be dealt with quite adequately by standard solutions.

Standard glazed cars are available from some of the larger manufactures but inevitably will come with their design limitations.

Hydraulic Lifts

Historically, hydraulic lifts provided an easy solution for the low-rise market and a potential answer to planning issues on mid-rise developments. The general problem is that, once hydraulic lifts are supplied in a busy office or hotel, or serves over six floors, then reliability problem will occur with greater frequency. The future will prove to be the expansion of the range of Machine Room-less lifts referred to below.

For special applications such as car lifts, hydraulic lifts will continue to be used and these will be provided by the smaller supplier companies as the larger multi-nationals concentrate on higher volume mass-produced equipment.

Hydraulic lifts cars are moved through the shaft by a ram located either beneath the car (direct acting) or a ram situated in the shaft (side acting). However, the direct-acting system is now frowned upon, because of the requirement for annual corrosion / defect inspection.

Travelling speeds are limited to a maximum of 1 m/s with cooling, and flight times are slow, as there is a need to start the pump and wait for the increase in hydraulic pressure before lift can move.

However, the hydraulic market may fight back for a limited time with series of new applications, but this may prove to be to little to late.

Eliminate the machine room

Skipping the machine room altogether is an architect's dream. You can now have lifts that fit into standard shafts with no need for the machine room. Remote or otherwise. Kone developed the concept and hold the patent for the term 'machine room-less' lifts. Other companies, however, have developed similar products: Otis with its Gen2, Schindler with the Mobile, and Thyssen with a similar range. Some of the independent companies can buy generic products that achieve the same result.

The concept is that the lift machine is housed at the shaft head and the controller is either located adjacent, in the shaft, or on the top-floor landing. All other elements of the lift design remain the same.

The present application for the range is mainly up-to 10 floors at speeds of between 1 m/s and 1.6 m/s.

For modernisation applications, Kone are the only company at present to offer any solutions. Its 'Monospace' product, re-engineered as 'Fury' offers variable geometry to suit most shaft applications in the capacity ranges of 4-13 persons. It should perhaps go without saying that this type of product will replace hydraulic lifts that are presently under performing in terms of speed or reliability.

The waiting game

Although lifts and escalators are design to a given standard design, the actual manufacture is 'to order'. The engineering of a particular scheme is only relevant to non-standard solutions and hence the lift industry requirement for longer contract lead-times. Current demand in the European market means that lead-times are 16 weeks for smaller high volume products, including escalators, 20 weeks for standard lifts and 26 weeks for bespoke equipment and solutions.

With the building industry responding faster to client requests, the lift industry is increasingly out of step. This increases the pressure on property professional, so we all need to think ahead and deal with the lift and escalator planning in the early stages of the project.

Modular Systems

For projects requiring fast installation modular systems can provide the solution. The machine room, each floor and the pit section are built off site. They are then delivered and installed on a timely basis and the either 'mothballed' or commissioned depending on the building's state of completion. The advantage is that the lifts can be delivered within the shaft enclosure and the interface with the other trades is minimal. Also, the equipment is assembled in a factory environment and the final product is therefore improved.

The down side is that it can be seen to be more expensive. The key to the equation is the structure costs. If the building can be designed to be structurally sound without the lift shafts being an integral element then the modular system can be designed accordingly. Shaft cladding costs can also be duplicated.

A design team will either see the collective benefits to make the concept work or choose to see the complications and bury the idea.

Glazed expression

None of the manufactures sells, as a standard, whole glazed front-wall enclosures but they are available from Selcom, Sematic and others. Look at Links www.wittur.com and www.sematic.com.

We have successfully used these designs in buildings with atrium spaces and shopping centres. See the Sheppard Robson case study below:

Picking the environs

Cars are the area that all Architects can influence. Adding bespoke stone floors can prove to be expensive as it may require upgrading the lift machine and safety gear systems. However, a stone design chosen from the manufacturer's range can be accommodated within the base design. Establishing the requirements early on is the key to your design freedom and not being constrained by other members of the team.

Short lead-times and highly specialised designs force the lift companies to use smaller fabricators with high levels of success. However, the architect or the consultant does need to take a great level of interest to ensure the product is as expected.

Finishing touches

With pushes and other operating fixtures try to use the manufacturers standard, if you want the costs to remain in the realms of normality.

However, there are specialists that support the industry e.g. CE Electronics, www.ceelectronics.com and Dewhurst, www.dewhurst.co.uk. are examples of this.

There are a number of new developments in information systems that are now available for lift cars. The larger companies have formed links with technology and media groups to supply news and other sales platforms that can be tuned to the user's requirements. The idea is that the technology will generate an income for the client, possibly off-setting the costs of lift maintenance.

It is also possible to install flat-screen televisions complete with sound systems blasting MTV or worse.

Going up

High Rise As we live in the UK, we may only have a few opportunities to actually be involve in the building process of one or two truly high rise buildings in our lifetime - that is buildings of more than 50 stories or 150m high.

As it stands now, too many only ever reach the design stage, often thwarted by the mesh of draconian planning restrictions.

I believe that the only high-rise buildings to gain planning permission will be mixed use and mainly residential at the top (serving a local need); with an office zone toward the middle and retail at the ground-floor zone, with car parking beneath. The idea of an office high-rise tower in the UK is off limits.

Up to 60 levels it is possible to 'elevate' buildings conventionally with a series of single-deck lifts, each bank serving elements of the building for the particular interest, residential, office and the like. Above this number of levels, one must consider double or triple-deck cars, depending on the office content of a given scheme. Sky-lobby stop off points are used every 25-30 floors.

The ultra high-rise 'tall' schemes (more than 150 levels) will require non-conventional systems that can transport more than one car per shaft and permit cars to travel horizontally, form one shaft to another. The technology is here. We simply have to wait the commercial opportunity to use it. This concept, known as the Odyssey system, was developed by Otis.

The escalators angle

They come in all sizes and two fundamental angles. They are available from 600mm in width, these are too narrow and a minimum width of 800mm is recommended. Escalators 1000mm wide are best suited to retail environment and 1200mm wide escalators can be found in some airports, particularly in the flat passenger walkway version. To increase the levels of safety only specify 30-degree escalators, unless particular site conditions warrant otherwise.

Escalators that are to be located in exposed locations can be specified accordingly. Such features will include galvanised trusses, waterproof switches, heating, lubrication systems, and so on.

There are a number of recent innovations that have been mainly architecturally driven. Check the after-sales service and agree good response times.

There is an information system being launched by most companies that with assist in communicating the safety messages and also provide advertising opportunities. The potential for client income in this area should not be overlooked although architecturally it is questionable!

Modern ethics

By the end of 2004, The Disabilities Discrimination Act will require all buildings to be made accessible to disabled people. Part M of the Building Regulations is the standard to be referred to.

Larger companies have subsidiary interests in this area. However, for specialised access solutions refer to www.uk-lift.co.uk and www.stannah.co.uk

Quality benchmarks

Ride quality is measured in a number of ways. Not quite as shake-rattle-and-roll but quake, jerk and a general measurement of background noise. Kone and Otis are the leading Western manufacturers promoting these issues, but if you intend to pursue these issues then be prepared to pay for it and have access to the measurement tools to quantify the results.

The quality of lift-system response times has been referred to above. Jerk rates (the rate of change of acceleration) and acceleration can be pre-set. These issues generally affect performance and the qualitative aspects of ride quality. As these issues potentially compete with each other, a balance needs to be established to achieve sensible values.

Once the equipment is installed, reliability levels can be agreed and if required penalties can be written into the maintenance contract.