283757893275

518 Barry’s Advanced Construction of Buildings
Lift car
FFL
Hydraulic ram
FFL
Pump
FFL
Lift pit
Figure 9.2 Hydraulic lift drive. FFL, finished floor level.
lifts require a smaller lift pit than traction lifts, since the pump can be located adjacent to
the hydraulic ram, as illustrated in Figure 9.2. The hydraulic ram can be side or rear
mounted, providing typical speeds of 0.15–1.0 m/s and a smooth operation. Where space
is at a premium, for example, in a refurbishment project, a borehole ram, which extends
into the ground, may be used.
Hydraulic lifts offer a number of benefits over traction lifts. Life cycle maintenance costs
may be lower, simply because there are less pulleys and lengths of wire ropes, hence less
wear. A hydraulic lift uses power only in the ascent; it uses gravity to descend and a small
amount of energy to operate the valves. Energy savings may be possible, compared with
traction lifts. The hydraulic oil has a long lifespan and will usually last the life of the lift. If
the oil needs to be replaced, it can be recycled. In an emergency, e.g. a power cut, the