Black Art or Simple Mathematics?

Lift traffic analysis began with the advent of modern buildings, dating back to the 1920s in the United States and the early 1950s in the UK.

In recent years there has been a transfer of expertise from the lift companies to independent consultants and in turn to property developers, letting agents etc., So, with time, greater understanding should explode the myth surrounding this 'art'. In attempt to hasten that process, Peter Boardman produced the graph (below) for a developer client.

Variables

Many variable have been taken into consideration when under-taking traffic
studies and these are:

1. Number of lifts
2. Speed of lifts
3. Car size
4. Anticipated building population
5. Probable number of lift stops
6. Door sizes
7. Passenger transfer times
8. Door delays and interference

Significant Factor

The number of lifts required will be directly proportional to the height and/or volume of the building and, therefore, the relationship of lift configurations can be tracked along the lines shown on the graph. Armed with these precise facts, the most significant factor of 'elevatoring' in buildings is to focus on the intended usage of the building, ie. single tenanted or multi tenanted, and establish the geographical location of the building in terms of external transportation systems. Flexi-time is here to stay so the number of lifts in buildings can generally be reduced, providing that parties - client, architect and designers - are focused and aware of lunch time peak periods, and concentrate their energies on the lift service received during this critical period.

All parties should discuss the relationship of lift service and waiting times during the up peak interval, which is only relevant as a function of the anticipated service during a lunch time period. However, generally speaking, clients, architects etc., are yet to focus on this crucial aspect of building design.

So, black art or mathematics? We can say that the solutions are mathematically based, overlaid with experience and focused on the ultimate service required.

Fire Fighting Lifts

BS5588 applies to buildings over 18 metres in height (travel distance) or nine metres in depth, measured from the access level. Fire fighting lifts are designed to operate in a core (including stairs and lobbies) designed for the purpose. The August 1991 edition of British Standards 5588 Part 5, introduced an aspect to the debate on the subject of fire fighting lifts in terms of their total integration to the vertical transportation system for passenger movement, rather than a separate facility.

The most significant changes included are as follows:

It is now permissible to have a 'through car' configuration providing that the fire fighting lift is not the sole fire fighting lift within the building. This enables the duplicity of service for both passenger movement on one entrance and fire fighting requirements on the other.

Additional protection is required to the lift car to avert any water spillage within the shaft affecting the electrical equipment. All finished must comply with Class O.

Maximise - Not Compromise

By strategically locating the lift shaft cores within the building, it would be possible to maximise on the nett available space required for core sizes without compromising the effectiveness of vertical transportation systems for passengers' or fire fighters' requirements.