1. LIFTS2. ESCALATORS

It is an appliance designed to transport persons or materials between two or more levels in a vertical direction by means of a guided car or platform.Lifts are required for tall structure to give comfort.

A lift is a vertical transport vehicle that efficiently moves people or goods between floors of a building. They are generally powered by electric motors that either drive traction cables and counterweight systems, or pump hydraulic fluid to raise a cylindrical piston.

By law the lift should be given only after the height exceeds 15m. The size of the lift depends upon the load and the number of persons using the lift.

A lift is essentially a platform that is either pulled or pushed up by a mechanical means. A modern day lift consists of a cab (also called a "cage" or "car") mounted on a platform within an enclosed space called a shaft. In the past, lift drive mechanisms were powered by steam and water hydraulic pistons.

In a "traction" lift, cars are pulled up by means of rolling steel ropes over a deeply grooved pulley, commonly called a sheave. The weight of the car is balanced with a counterweight. Sometimes two lifts always move synchronously in opposite directions, and they are each other's counterweight.

The friction between the ropes and the pulley furnishes the traction which gives this type of lift its name.

S No.

Description Hydraulic Lift Traction Lift

1. Machine room In the basement or at ground floor.

Usually at the top of the building.

2. Machine room size Minimum 4 sq.m. 16 sq.m.

3. Size of lift shaft 10-15% smaller cause there is no counter weight.

10-15% more than hydraulic lifts.

4. Civil work co-ordination

Not required. Essential.

5. Erection time Less time in erection and also less complicated.

Less possibility of reduction in time and complicated erection.

6. Travel Maximum height 21m. No limitations.

7. Speed Slow speed lifts. High speed lifts also possible.

8. Maintenance Quick and simple. One has to climb right up to the machine room.

9. Efficiency High. Moderate.

10. Installations Less time and simple. More complicated and more time consuming.

11. Power consumption

Require power only for upward direction .

Requires power for moving in both the direction.

Due to less area required for machine room and due to less size of well there is saving of the floor space.

They do not require ropes, pulleys, counter weight etc.

1. Machine room: The part of the lift equipment comprising motor(s) and the control gear. The movement of the lift is sensed by control panel when the button of the lift is pushed. The control panel controls the main movement of the cage or car. The machinery has an isolated switch to cut off the movement of the cage.

The whole of the machinery consists of the driving system. The machine room must have a temperature of 10-40degree. Driving system consists of a motor driven by electric power of 3-30kN.

Motor is the AC motor which drives the whole system through the shaft.

The total load which is to be carried by the motor

= dead load + live load – ½ of the counter weight.

The walls of masonry should be minimum 230mm. All the four walls should be in straight vertical line to give easy lift movement.

2. Lift pit:

The space in the lift well below the level of he lowest lift landing served. Pit is provided with minimum 2 buffers for cars to absorb the shocks in accidental cases. These buffers are in the form of spring. The depth of the water proof pit is 1400mm minimum.

3. The shaft (lift well):

The unobstructed space within an enclosure provided for the vertical movement of the lift car(s) and any counter weight(s), including the lift pit and the space for top clearance.

CABLES/ROPES:

• Both the cage and counter weight are driven by ropes.• Ropes are made by HIGH TENSILE STEEL wire.• Depending upon the amount of load a car has to carry the number of cables vary from 4 to 12. It also depends on speed of the lift.• The diameter of the cables vary from 9 to 19mm.

The cage or car is the carrier of the people and the goods. The car is suspended through a pulley by steel ropes. To counter weight the load of the car there is always a counter weight at the bottom in the water proof pit to maintain a balance.

As central as possible. It should be close to the entrance and also to the staircase.

Close to the staircase reduces the demand and load. It s preferable to group the lifts and not scattering them. It

increases the efficiency and offsets the waiting time and also deceases the builders work, erection will be fast. Maintenance becomes easy. It also helps in having 1 machine room than having 3-4 machine rooms for 3-4 lifts.

Location of the lift should be easily seen from the entrance especially in commercial and shopping complex.

In hospitals, it should be close to the operation theatres. Lobby of the lift should be wide enough for free flow of

passengers. Waiting people should not obstruct the passage.

Number and size is related to following considerations:

Population of building (no. of passengers). Type of occupants (type of building for e.g. hotel,

office, apartment, etc.). Starting and finishing time of population. No. of floors and height of floors. Quantity of service (no. of passengers at the peak

period)to be provided to the occupants. Quality of service (is measured in waiting time of

the passengers) to be provided to the occupants.

For office buildings: if 1 lift is provided for every 3 floors than quality is said to be excellent. If 1 lift is provided for 4 floors than it is rated as average. And if 1 lift is provided for 5 floors than it is rated as below average.

For other type of buildings NBC provide standard criteria for quality of service.

S No. Occupancy Gross area in meter square per person

1. Residential 12.5

2. Education 4.0

3. Institutional 1.5

4. Assembly buildings 1.5

5. Mercantile like shopping centers

3

6. Business and industrial 10

7. Storage or warehouses 30

8. Storage of hazardous goods 10

9. Dormitories, orphanages, home for aged, etc.

7.5

This time is taken in seconds for a single lift to travel from ground floor to topmost floor including all probable stops and than returning to ground floor.

RTT is the sum of the time required in the following process:

a) Entry of the passenger on the ground floor.b) Exit of the passengers on each floor of discharge.c) Door closing time before each starting operation.d) Door opening time on each discharging operation.e) Acceleration periods.f) Stopping and leveling periods.g) Periods of full rated speed between stops and going

up.h) Periods of full rated speed between stops and going

down.

S No.

Speed

(m/s)

Lift travel in meter

Flats Luxury flats

Offices Hospitals

1. 0.25-0.4

- - - 5

2. 0.50 30 15 10 10

3. 0.75 45 20 15 15

4. 1.00 55 25 20 20

5. 1.50 - - 30 45

6. 2.50 - - 45 100

7. 3.50 - - 60 -

8. 5.00 - - 125 -

Lifts are classified in 4 ways depending upon :

Type

Control

Speed

Type of doors

Passenger lift

Goods lift or service lift

Hospital lift

Fireman’s lift

Also referred as freight lift or service lift. It is just like passenger lift but less decorative but comparatively

large. Tough and strong body so that it can withstand the abrasion due to

placement of goods in car. Speed does not exceed 1m/s. They have to have accurate floor leveling to have wheeled trolleys. Besides carrying goods they have to carry 1 or 2 attendants. For offices, if the lift have to carry documents, stationery, registers

than their usual speed is 0.4m/s and load is only 10-35kgs. When smaller type of goods have to be carried than speed is

between 0.25-0.5m/s. For larger type of goods the speed is 0.5m/s. Depending upon the requirement the size of the lift may vary

considerably. In hotels these lifts are provided for food services, than the speed is

0.4 m/s (when used in hotels they are called dumb waiters).

It is used to move sick passengers.

They are slow speed lifts.

It should have a perfect leveling with the floor.

Minimum depth of the car has to be 2.4m.

Minimum width of the car is 1.4m so that the doctors can stand.

Minimum height of 2.2m.

It has to be planned in such a way that it is accessible from outside.

For buildings having height of 15m or more at least one lift shall meet the requirements of fireman’s lift.

Lift landing doors shall have a minimum of fire resistance of one hour. Doors shall be of automatic operation for car and landing.

For fireman’s lift in a building having more than 15m or more height, shall work at or above the speed of 1.0m/s so as to reach the top floor from ground floor within one minute.

It must have a capacity to carry 544kgs.Minimum floor area of the lift 1.44per square meter.

It should have a special switch at the lowest end to decontrol all the calls of the lift and bring it down immediately straight to ground floor.

It is operated manually after taken over by fireman. The lift shall be provided with the following as a minimum:

a) A two position switch at evacuation floor (normally main entrance floor) (ON/OFF).

b) Buzzer and fireman’s lift - light in car.

METHODS OF CONTROL SYSTEMS1. AUTOMATIC PUSH BUTTON OPERATION2. ATTENDENT AND DUAL CONTROL

TYPE OF CONTROL SYSTEMSa) COLLECTIVE CONTROLb) SINGLE PUSH COLLECTIVE CONTROLc) DOWN COLLECTIVE CONTROLd) DIRECTIONAL COLLECTIVE CONTROL FOR ONE CARe) DIRECTIONAL COLLECTIVE CONTROL FOR 2/3 CARSf) GROUP SUPERVISORY CONTROL

Automatic control is a method of operation by which a momentary pressure on a push button sets the car in motion and causes it to stop automatically at any required lift landing. This is the simplest control system and it is sometimes referred to as push button control.

A car answers a landing or car call whichever is actuated first by momentary pressure provided the lift is not in use. Momentary pressure of a car push button will send the car to the designated floor. The car always responds to a car push button preference to a landing button.

This type of control is recommended for the following applications:

a) A single passenger lift serving up to 4 floors.b) Goods lift serving any number of floors where it is

usually the most suitable form of control.

Collective control is a generic term for those methods of automatic operation by which calls made by pressing push buttons in the car and at lift landings are registered and answered by the car stopping in floor sequence at each lift landing for which calls have been registered irrespective of the order in which the calls have been made, and until all calls have had attention.

Collective control of any form is usually not suitable for goods lift except where loading is not expected to fill the car and additional loads can be taken at other stops.

Single push button collective control has a single push button at each landing. It is not recommended, as the direction in which it is desired to travel cannot be registered by the intending passenger.

Down collective is a control system where landing calls are registered from a single push button, irrespective of the car being in motion or the landing door being open and calls are stored until unanswered. Any number of car calls can be registered and the car will stop in sequence in the down direction at each of the designated floors. The car will travel in the up direction to the highest call registered stopping only in response to car calls. It will then travel downwards answering calls in floor sequence. If only one call has been registered the car travels to the floor of call.

This system is suitable where there is traffic between the ground floor and upper floors only and no inter floor traffic.

With this type of control the following signals are included:1. A landing signal light indicates that the call has been

registered and will be answered.2. Illuminated car position indicator above car entrance.

Directional collective control for one car is a control system having UP and DOWN push buttons at intermediate landings whereby the call is registered for the intended direction of travel. Calls from the car or landing push buttons are registered and stored until answered. The car will answer calls in floor sequence in one direction of travel. Calls for the opposite direction of travel are answered when the direction of travel is reversed. This system is suitable for single lifts serving 4 or more floors with inter floor traffic, such as small office blocks, hotels, etc.

With this type of control the following signals are included:1. A landing signal light for each landing push button indicates that

call has been registered and will be answered.2. Illuminated car position indicator above the entrance in the car.3. Arrow shaped signal lights in the back of the car or on the

landing to indicate to the entering person in which direction the car is going to depart.

Directional collective control for 2/3 cars is a system covering a control in which the 2/3 cars in a bank are interconnected. One push button unit with UP and DOWN push buttons or floor buttons are required at each landing and the call system is common to all lifts. Each landing call is automatically allocated to the best placed car. The control is designed so that cars are effectively spaced and thus give even service. When a car reaches a highest floor to which there is a call its direction of travel is automatically reversed when it next starts.

With this type of control the following signals are included:1. A landing signal light for each landing push button to indicate

that the call has been registered and will be answered.2. Illuminated car position indicator above the entrance in the car.3. Arrow shaped signal light in conjunction with an audible single

stroke gong or an indication on the landing call push button station above each landing entrance to indicate to the waiting person(s) which car is going to stop and in which direction it will continue its course.

A bank or group of intensive traffic passengers lifts require a supervisory system to co-ordinate the operation of individual lifts which are all on collective control and are inter connected.

This system regulates the dispatching of individual cars and provides service to all floors as different traffic conditions arise minimizing such unproductive factors as idle cars, uneven service and excessive waiting time. This system will respond automatically to traffic conditions such as UP and DOWN peaks, balanced or light traffic and provides for other specialized features.

If desired, a master station can be provided in the lift lobby which gives by indicators, visual information regarding the pattern under which the system is operating.

It is dependent upon the quantity of service required and the quality of service desired. Therefore, no set formulae for indicating the speed can be given. However, the following general recommendations are made:

NO. OF FLOORS SPEED(m/s)

4-5 0.5-0.75

6-12 0.75-1.50

13-20 1.50-2.50

ABOVE 20 2.50 AND ABOVE

Collapsible door.

Swing door.

Central opening (manual or automatic arrangement).

Single sliding (manual or automatic operation).

Vertical by-parting (manual or automatic operation).

Vertical single sliding (slide up or down, manually or automatic operation).

Central opening (automatic).

The drawings of the buildings should give the following particulars and finished sizes:

1. No. of lifts and size and position of lift well.2. Particulars of lift well enclosure.3. Size, position, no. and type of landing doors.4. No. of floors served by the lift.5. Height between floor levels.6. No. of entrances.7. Total head room.8. Provision of access to machine room.9. Provision of lighting and ventilation in machine room.10. Height of machine room.11. Depth of lift pit.12. Position of machine room.13. Size and position or supporting steel work at roof levels.14. Size and position of any footings or grillage foundations, if

these are adjacent to lift pit.15. In case of passenger lifts whether the lift cage is required to

carry household luggage, such as refrigerator, steel almirah, etc.

They are also referred as powered stairs. Stairs in which tread moves automatically. It can move in upward and downward direction.

It is required in places where the movement of people is quicker. Essentially it is a bridge between two floors.

This type of equipment does not require any operator. Neither one has to wait to move either in upward or downward direction.

It requires low power consumption than the lifts and also have large passenger handling capacity.

These appliances proves ideal for air-port, exhibition halls, departmental stores, etc.

As the escalators operate at a constant speed, serve only two levels and have a known maximum capacity, the traffic study is rather easy. Provided the population to be handled in a given time is known, it is easy to predict the rate at which the population can be handled.

For normal peak periods, the recommended handling capacities for design purposes should be taken as 3200 to 6400 persons per hour depending upon the width of the escalator.

Angle of inclination shall not be in excess of 30 degree from the horizontal.

The depth of any step tread in the direction of travel shall not be less than 40cm and the rise between treads shall not be more than 22cm. The width of a step tread shall be not less than 40cm or more than 102cm.

Landing shall be made out of anti-slip material.

For normal peak periods, the recommended handling capacities for design purposes should be taken as 3200 to 6400 persons per hour depending upon the width of the escalator.

The number of persons that may be theoretically carried by the escalator in 1 hour can be calculated as:

a) For determination of theoretical capacity it is assumed that one step with an average depth of 0.4m can carry one person for a step width of 0.6m, 1.5 persons for a step width of 0.8m and 2 persons for a step width of 1.0m.

b) The theoretical capacity then is:=3600*(rated speed in m/s*k)/0.4

Where k = 1,1.5 or 2 for 0.6,0.8 and 1.0m step widths.c) Some values are calculated as per the above are:STEP WIDTH THEORETICAL CAPACITY IN PERSONS/HOUR

0.5m/s speed 0.65m/s speed 0.75m/s speed

0.6m 4500 5850 6750

0.8m 6750 8775 10125

1.0m 9000 11700 13500

It is reversible to suit the floor. Its direction can be reversed.

It can be used even when it is stationery.

It can be used for short height.

Speed varies from 0.45-0.60m/s. Slow speed because it is considered to be the safe velocity for entrance and exit.

But in specific areas where the population is increased, the speed can be 0.7m/s.

The nominal width or step width varies from 600-1200mm.

600mm-for small buildings.

800mm-for departmental stores & banks.

1200mm-largest size, normally used where passenger moves along with luggage & also for very large departmental stores where there is heavy traffic.

OVERLOAD RELAYS: In case there is increase in supply of voltage due to electric current fault, it will trip off or stop the functioning of escalator. If there is any mechanical defect it pressurizes & trips off the motor.

INTERLOCK CONTACTS: If the chain breaks at any point or unduly stretched, the functioning of escalator stops.

OVER SPEED GOVERNOR: If there is increase in the movement of steps it automatically applies the brake.

STOP SWITCHES: It is connected to the hand rail. If anything is caught in the hand rail than it automatically stops the function of escalator.

PROVISION OF COMB PLATE LIGHTS: These lights are provided at top junction. A person can see the levels very clearly. The moving step and the stationery landing area.

Easily visible from entrance and in case of departmental stores it should be visible from large distance.

Clear and enough landing space for passenger in both the directions.

Not to be placed at dead ends or cul-de-sac.

Moving pavements, horizontal moving surfaces essentially for horizontal movement.

Maximum inclination provided 12-15 degree.

Speed 0.6-1.33m/s.

It is ideal for airports, railways & shopping centers. The width varies from 600-1000mm. This arrangement can be ideal for buildings for handicap persons on wheel chair. For operating there are switches on both ends.

Lift cages are one after the other with capacity of two persons with no db oors. Size of each car is 1m*1m. In one shaft pair of 2 cars one going up and other coming down.

Slow speed of 0.426m/s. These are usually planned at the university or school or

where people are young. Only advantage:

Hardly any waiting period due to continuous movement.

Disadvantages: Maximum floor it can travel is 7 (G+6).Makes lot of noise.Front side is open, fire and smoke can easily travel

from one floor to topmost floor

The complexity of a paternoster's mechanical system is quite low: two endless chains lead through the hoistway at opposite corners. The cars are supported diagonally by both chains. A view on the picture (left) easily shows, what seems to be so hard to understand when explained in words.

The picture shows the patenoster without it's safety features in order to show just the principle of movement. The cars go up on the left side of the shaft and back down on the right side.

The attachment of the cars to the chains is crucial: the upper, right corner of each car-frame is connected to the front chain, the upper, left corner to the chain in the back. The distance between the spots in which the car-frame is connected to the chains stays constantly the same for the whole travel of the paternoster. The virtual axis through these spots stays horizontally, so does the car frame and thus the entire car.