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516 Barry’s Advanced Construction of Buildings
Coordination and tolerances
An essential requirement when designing and planning buildings that utilise lifts and
escalators is the coordination of dimensions. Lifts and escalators are manufactured to
precise dimensions, and manufacturers set out specific requirements for the amount of
tolerance in the built structure that supports and/or encloses their equipment. Failure to
coordinate dimensional drawings prior to construction, and especially failure to liaise
regarding any changes that occur during construction, may result in considerable rework
on site. Critical dimensions are the finished floor to finished floor dimensions, the internal
size of lift shafts, the width and height of the structural opening to the lift shaft, the pit
depth (ground floor level to bottom of pit) and the headroom (height from the top of the
lift car exterior to the top of the lift shaft). The lift shaft must be constructed plumb and in
accordance with the vertical tolerances provided by the lift manufacturer. The formwork
and finished concrete shaft must be regularly checked as work proceeds to ensure the work
is within the specified tolerance.
The widespread use of laser levels for setting out and checking work as it proceeds,
together with the use of steel formwork, has helped to improve the accuracy of concrete
poured in situ. Similarly the use of prefabricated units can assist in helping to achieve more
accurate work. However, the quality of the work on site remains a determining factor. The
work must be accurate, thus ensuring that there are no problems when the lift machinery
is delivered to site. This requires high-quality work, supervision and methodical checking
of the work as it proceeds. Critical areas/dimensions are discussed further.
Electrical supply
A suitable electrical supply will need to be made to the apparatus (lift car, escalator,
walkway) as well as to the motor room, and in the case of motor roomless lifts, the lift
shaft. The motor room will require lighting and emergency lighting. The lift shaft will need
to be lit at the top and bottom with intermediate lights spaced at a maximum of 7 m. Thirteen
amperes switched electrical outlets will be required in the motor room and the lift
shaft for power tools. Heating, ventilation equipment and thermostats will also be required
to maintain an ambient temperature (as specified by the lift manufacturer). The lift car will
require lighting and emergency lighting.
9.2 Lifts (elevators)
The development of the skyscraper is dependent on developments in safety and speed of
passenger lifts (elevators). Lifts are, however, not the sole domain of high-rise buildings,
being a common feature in the vast majority of buildings with a change of level. There are
a relatively small number of well-known manufacturers and installers of lifts. Therefore
choice of manufacturer is rather limited, although the choice of lift car size, its performance
and internal finishes are quite extensive, with lift cars designed and manufactured to suit
the requirements of a particular development. For many small- to medium-sized developments,
there are a standard range of lift sizes available from a standard range. The quality
of the lift car will be determined by its function. For example, a lift car that carries people