The space constraint
has forced the construction industry to move vertically in metro cities in
India. As the building height increases, the need for enhanced elevator speed
also increases. This has opened new avenues of technology for the elevator
manufacturer in India. Rajnikant Lad, Chartered Engineer & Elevator
consultant at Shree Jee Elevator Consultants gives an account of the latest
innovations and options available in the field of vertical transportation.
Building height is the main
deciding factor for the speed of the elevator. With an increase in speed, we
have to meet new challenges of riding comfort, operational efficiency, energy
efficiency, earthquake consideration and many more aspect of safety and rescue
during emergencies. This has made the elevator industry more and more
technology-driven.
We see a fast change in
elevator requirement in the country which has gone up to 40,00045,000 per year
and is bound to increase year by year. The elevators with speeds of 0.65m/sec
and 1.0m/sec to maximum 2.5m/sec were used till the year 2000. Now elevators
with a speed of 2.5 m/sec are very common and the maximum elevator speed
available is 6m/sec.
As per present rules, building
above 70m is considered a high rise building. The same is under consideration
for an amendment to increase to 120m. This will further boost the highrise
elevator market and in turn, invite faster technological development. The
present market requirement and future business prospect in India have attracted
the entire international leading elevator manufacturer to have their presence
in India. The business growth, presence of major International elevator players
and increasing
building height has given new
dimensions to the Indian Elevator Industry. We have now all the latest elevator
technologies available in India. Whether it is touch screen system, Intelligent elevator monitoring system,
full-length infrared door safety screen, hydraulic elevator, vacuum elevators, capsule elevator, destination control
system, machine room-less elevator, Variable Voltage Variable Frequency (VVVF)
drive system, and gearless drive all are now available in India.
Shortly, we may also witness
Double Decker and Twin elevator systems in upcoming buildings. Some of the
latest technological developments include:
Destination
Control System
This is the latest in the
elevator control system. In this system one has to press the number of the
floor he intends to visit. The system will collect this information and analyze
the movement and location of the elevators moving in that group. After
analyzing, the call will be assigned to the elevator which will come in minimum
time and provide minimum riding time to that passenger. The display system
provides the lift number which will attend to the call of the passenger. The
passenger notes the lift number and boards that elevator. There are no buttons
provided inside the lift cabin.
Double
Decker Elevators
The Double Decker system is
used to optimize the core building area in tall buildings. We can have more
free space area available in a building by incorporating two elevators in the
same shaft. This system has its own advantages and disadvantages.
1.
t
provides high efficiency during peak hours as the car stops at two adjacent
floors at the same time. But during light traffic, heavy car masses have to
move using unnecessary energy. Passengers may encounter waiting time when
another car is loading /unloading
2.
Two
entry levels are required on all floors. • All cars in a group must be a double
deck.
3.
Double
Decker elevators are preferred as an express shuttle to serve sky lobbies and
have not been introduced in India so far as they are not yet economically
viable.
Twin
Elevator System (Two
Elevators In The Same Shaft)
In this case, we have two cars
moving independently in the same shaft. The cars use the same guide rails and
the same landing doors. Minimum clearance between both cars is guaranteed by a
special safety concept. With the use of double entrance, we can see excellent
results of uppeak traffic. It consumes less energy compared to the Double
Decker system and results in lower operational costs. Still this is not
considered a commercially feasible solution in India.
Machine
Roomless Elevators (MRL)
The introduction of synchronous
motor and VVVF drive system and PU coated flat wire ropes has made the elevator
manufacturer job easy. This has helped in reducing the overall weight of the
machine unit to a great extent. With the reduction in size and weight of the
machine unit, it has become possible to install it inside the elevator shaft.
The size is so small that it can be installed inside the lift shaft at the top
in a small space. These are now termed as machine room less MRL elevators.
Beside small in size and light in weight, it is also energy efficient. With the
gearless unit and use of VVVF drive system, we can save energy up to 50% as
compared to the conventional elevators.
Full-Length
Infrared Door Safety System
The introduction of full-length
infrared door safety system has made the door closing operation more safe and
reliable. The problem arising out from the use of mechanical safety and
photocell system is now totally overcome. This latest safety system detects
even a small obstruction during door closing operation. The doors immediately
stop closing operation, avoiding the possibility of an accident.
Need
For A Professional Approach
When the subject becomes more
technology-driven, you need to have experts from the field to assist you in
planning the right thing for your requirement. Elevator consultant plays a
great role in deciding the right technology for a particular project. If he is
involved from the drawing board stage with a particular project, he can be of
much help in deciding elevators/escalators which can offer maximum efficiency,
comfort and safety combined with cost-effectiveness. Some of the points which
need to be studied before finalizing the technical specification are:
1.
Type
of project (residential, commercial, a mix of residential and commercial,
hospital, office building, mall etc.) • Building height
2.
Building
occupant population and floor area served
3.
Floating
population and its timing in case of office, hospital, commercial complex
4.
Height
restriction from the statutory point of view or from construction point of view
• Noise level requirement inside building or at particular floor/area
5.
Handling
capacity and waiting for time requirement(traffic analysis
6.
Future
expansion plan Possible change in building occupancy in future
While considering the speed,
one has to follow that the elevator must be able to cover travel distance from
the bottom floor to the top floor in 60 seconds as required under fire lift
norms. This gives a clear deciding factor for elevator speed. Besides height,
one has to study the passenger handling requirement. For normal consideration,
the elevator should be able to handle 10 to 15 per cent of the building
population in five minutes in a diversified building and the waiting time of
passenger at various floor should not be more than 20 to 25 seconds.
The study of the type of
passenger flow morning peak, evening peak, intermediate floor to floor traffic
and lunch break traffic is based on the type of occupancy of the building. An
office building will have different traffic pattern as compared to a mixed-use
commercial building having offices, restaurant, hospital and even residential
blocks on the top portion of the building.
In all our elevator decision,
we should provide one stretcher elevator and one good elevator with a wide
opening. Provision must be made for the use of elevators by differentlyabled
persons too. Furthermore, whether it is an office building or residential
building, the need for stretches /good transportation is inevitable. Providing
one elevator as a stretcher and one as goods elevator will solve several
problems of the users.
The fastest elevator available
at present in India has a speed of 6m/sec at Imperial Twin TowerMumbai 254m
high and the same will be superseded by project under construction named
Polaris Royale 300+m high with elevator speed of 7m/sec. This is going to be
challenged further by World One400+m with elevator speed 8m/sec and India
Towers, 700m high with elevator speed of 9m/sec.
Elevator
Safety Considerations
While designing an elevator
located in a building, one must consider the possibility of use of elevator
during fire emergencies. By locating few elevators which opens opposite to the
normal wind direction (west opening), and are located on the outskirt of the
building will facilitate better used during the fire.
The one important factor missed
generally or not given due importance is the maintenance requirement for
elevators. We must provide a trap door in the top floor and in the machine room
floor which helps to lift/shifting heavy machine unit during major repair in
the longer run. The elevator machine room approach and entrance must be kept
wide enough (passage/steps minimum 1.5m wide and entrance door opening minimum
1.0m.)
The hydraulic lift/vacuum
elevator is used in bungalows or duplex flats where space becomes the main
constraint. This may lead to compromising on machine room space and safety. The
machine room location, dimensions and approach must be made in such a way that
during an emergency, one can easily enter machine room and carry out
repair/rescue work. There has to be good provision for the inside passenger to
communicate with the outside world through intercom/speak phone or any better
communication means. This helps trapped passenger get connected with the
outside world and stay relaxed.
The increase in elevator
installations and building height has been forcing us to rethink on the related
safety issues. The fire brigade has its restrictions for the height of the
ladders. We have to study further for a better and suitable system to address
emergency rescue during fire, earthquake and other emergencies.
Safety awareness is one of the
means for ensuring safe travel in the elevator. Safety training must be carried
out by elevator contractors with frequent intervals. Considering the present
elevator demand and continuous increase shortly, it has become imperative for
the elevator industry to create technical knowledge bank in the country. The
technical institutions in India must consider the elevator subject as part of
their regular study and create sufficient good quality technical workforce.
.
Written
By : Rajnikant Lad
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