Table of Contents
Classification of Lifts
The lifts are classifies based on usage, speed and motor drive as below:
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USAGE:
- Goods Lift.
- Passenger Lift.
- Service Lift.
- Hospital Lift.
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SPEED:
- Slow speed, v < 1.0 m/s.
- High speed, v > 1.0 m/s.
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MOTOR DRIVE:
- Geared.
- Gearless.
Selection of Lifts
For selection of a Passenger lift, following factors are considered:
Quantity of service: It is a measure of passenger carrying capacity during 5 minutes peak period of day and is also known as passenger handling capacity (H). Following is the criterion followed:
- 10 - 15 % for diversified tenancy buildings.
- 15 - 20 % for single purpose occupancy.
- 7.5 % for residential building.
Quality of service: Generally measured by passenger waiting time during peak period, and is classified as follows:
Waiting Time | Quality | No of floor | Speed |
---|---|---|---|
20 - 25 s | Excellent | ||
30 - 35 s | Good | 4 - 5 | 0.5 to 0.75 m/s |
35 - 40 s | Fair | 6 - 12 | 0.75 to 1.5 m/s |
45 s | Poor | 13 - 20 | More than 1.5 m/s |
More than 45 s | Unsatisfactory |
Note
For residential buildings, longer intervals upto 90 seconds are permissible.
Determination of no. & capacity: The capacity calculation is done as in the procedure and example outlined below. The various terms associated with the Lift operation are:
- Total travel of lift: Total travel of lift from ground to last floor.
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Round trip time: Total time taken by the lift to pick up the passenger to the capacity from ground floor, unloading them at various floors and come back to ground floor. It includes:
- Time required for passengers to enter at ground floor (i) - 3 seconds.
- Exit of passengers at each discharge (ii) - (F-1) × 2 sec.
- Door closing time (iii) - F × 2 seconds.
- Door opening time (iv) - F × 2 seconds.
- Stopping and leveling time (v) - F × 2 seconds.
- Acceleration period (vi) - 10% of (i + ii + iii + iv).
- Total travel time (vii) - (2 × maximum distance traveled in one direction) / speed of lift.
Then Round Trip Time : (i) + (ii) + (iii) + (iv) + (v) + (vi) + (vii).
Note
F is the number of floors including ground.
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Handling Capacity (H): It is a measure of how many number of passenger in percentage can be handled within 5 minutes of the peak hours.
H = (300 × Pc × 100) / (T × Q).
Where,
Pc = Average no. of passengers carried in a car = 80 % of P.
P = Capacity of lift e.g. 10, 13 etc.
T = Waiting interval = RTT / n.
n = number of lifts.
Q = Total number of passengers to whom service of lift is provided.
Design Criterion:
Residential Building : 5/6 persons per flat.
Office Building : 100 ft²/person.
Technical Building : 400 ft²/person.
Note: Weight of a person is considered to be 68 kg.Example:
G + 3 technical building, floor height 5 m.
4th to 8th floor for administrative purpose, floor height 4 m.
Area of each floor = 1500 m² ≈ 15,000 ft².
Let lift capacity is 10 persons (P = 10) and speed is 1.5 m/s (v).
Total travel of lift = 4 × 5 + 5 × 4 = 40 m.
Number of persons (Q) = 4 × 15 000 / 400 + 5 × 15 000 / 100 = 900.
RTT = 3 + 8 × 2 + (9 × 2) × 3 + 0.1 (3 + 16 + 36) + 2 × 40 / 1.5 = 145 seconds.
So far n = 4, T = 36 seconds and H = 7.40 %.
Comparison of lifts: Comparison of lifts is given in the table below:
Single Speed Lift | Two Speed Lift | Variable Voltage Lift | Gearless Lift |
---|---|---|---|
Residential Buildings | Office and Telephone Exchanges | Office and Telephone Exchanges | High Rise Buildings |
Up to 5 floors | 5 to 12 floors | 5 to 15 floors | Above 15 floors |
0.3 to 0.65 m/s | 0.75 to 1.0 m/s | 1.0 to 1.5 m/s | 1.5 to 2.5 m/s |
Power door not advisable | Power door recommended | Power door recommended | Power door recommended |
Single call control or semi-dual push button control | Selective and collective | Selective and collective | Selective and collective |
Automatic rescue device is not possible | Automatic rescue device is possible | Automatic rescue device is possible | Automatic rescue device is possible |
Fireman switch can be provided | Fireman switch can be provided | Fireman switch can be provided | Fireman switch can be provided |
Typical Dimensions of Lift: Dimension of lift in mm for speed upto 1.5 m/s. (All dimensions are with reference to plan of machine room given below)
Capacity | Capacity (kg) | A | B | C | D | E |
---|---|---|---|---|---|---|
04 | - | 1100 | 780 | 1900 | 1300 | 800 |
06 | 408 | 1100 | 1000 | 1900 | 1600 | 800 |
08 | 544 | 1300 | 1100 | 1900 | 1900 | 800 |
10 | 680 | 1350 | 1300 | 1900 | 2100 | 800 |
13 | 885 | 2000 | 1100 | 2500 | 1900 | 900 |
16 | 1088 | 2000 | 1300 | 2500 | 2100 | 1000 |
20 | 1360 | 2000 | 1550 | 2500 | 2400 | 1000 |
Goods (Telephone Exchange) | 3000 | 1500 | 4000 | 2500 | 4500 | 1500 vertical bi-parting door |

Trap Door : 1500 × 750 / 1500 × 1000 with a hook of 1500 kg capacity in center for passenger lift and 1950 × 1150mm with a hook of 3000 kg for goods lift.
Clearance between machine room and last floor served:
= 4800 mm for speed upto 1.5 m/s.
= 5600 mm for speed more than 1.5 m/s.
Lift pit height:
= 1600 mm for speeds upto 1.5 m/s.
= 2600 mm for speeds more than 1.5 m/s.
Width and depth same as lift well.
Relevant IS
IS 3534 : 1976 - Dimensions of Lift.
IS 4666 : 1968 - Specifications for passenger and goods Lift.
IS 1860 : 1968 - Operation, Installation and Maintenance.
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