Vertical Transportation Design and Traffic Calculations – Part Five


In Article “Vertical Transportation Design and Traffic Calculations – Part Two, we indicated that the Principles of Interior Building Circulation are:
  1. Efficiency of Interior Circulation,
  2. Human Factors,
  3. Circulation and Handling Capacity Factors,
  4. Location and Arrangement of Transportation Facilities.

Also, we explained the first principle; Efficiency of Interior Circulation in above article and explained the human factors in article “Vertical Transportation Design and Traffic Calculations – Part Three”.
And we indicated that the Circulation and Handling Capacity Factors will include:

  1. Corridor handling capacity,
  2. Portal handling capacity,
  3. Stairway handling capacity,
  4. Escalator handling capacity,
  5. Passenger Conveyors (Moving Walkways and Ramps) handling capacity,
  6. Lifts Handling Capacity.

 And we explained the first four items in article Vertical Transportation Design and Traffic Calculations – Part Four”.
Today we will continue explaining other Principles of Interior Building Circulation.

 

Principles of Interior Building Circulation


Third: Circulation and Handling Capacity Factors


5- Passenger Conveyors (Moving Walkways and Ramps) Handling Capacity

 
 
There are (4) Factors affect the Passenger Conveyors handling capacity as follows:
 
A- Speed:
 
The running speed is determined by the angle of inclination. The speed as in the escalators is measured in the direction of movement of the steps or pallets, ie: along the horizontal.
 
B- Step Width:
 
The available widths are:
 
1000 mm
Common step width
1400 mm
Easily allows two stationary files of passengers or the possibility a stationary file and a walking file of passengers on the moving passenger conveyor.
 
 
C- Inclination:
 
The available escalator s’ inclination is:
 
Walkways
inclination of 0°
ramps
inclinations in the range 3° to 12° although the maximum is generally 10° and the practical is 8°.
 
D- Density of passengers:
 
 
A passenger conveyor theoretically should permit denser congregations of passengers than an escalator, as the space is not rigidly defined by steps. In practice, the probable density will be about 2.0 Person/m2.
 
The theoretical handling capacity of a Passenger Conveyors (Cc) in person/minute is given by equation (1):
 
Cc =60V D W              equation (1)
 
Where:
 
Cc is the corridor handling capacity (persons/minute)
V is average pedestrian speed (m/s),
D is the average pedestrian density (persons/m2),
W is the effective corridor width (m).
 
 
Table-1 indicates practical handling capacities in persons per minute and persons per hour (bracketed) assuming a density of 2.0 persons/m2, using Equation (1.1).
 
 
Incline (degrees)
Speed (m/s)
Width of passenger conveyor (mm)
1000
1400
0
0.50
60
(3600)
84
(5040)
0
0.63
76
(4560)
106
(6350)
0
0.75
90
(5400)
126
(7560)
5
0.70
84
(5040)
-
-
10
0.65
78
(4680)
-
-
12
0.50
60
(3600)
-
-
Table-1 Handling Capacities of Passenger Conveyors
 


 
6- Lifts Handling Capacity

 
 
In article “Vertical Transportation Design and Traffic Calculations – Part Three” , we indicated that Passenger s’ body Constraints as per European Standard EN-81 is as follows:
The recommended design density for passengers, when sizing a lift car in European Standard EN-81 uses a complicated formula which allows
 
Density (person/m2)
Car Capacity
0.1 m2 plus 0.2 m2 per person
up to 6 persons
0.15 m2 per person
up to 20 persons
0.12 m2 per person
more than 20 persons
 
This implies that when riding in a 6-person car, each passenger can occupy 0.22 m2, but when in a 33-person car the same passenger is only allocated 0.15 m2 of space. These values in above table require passengers to be very crowded in a large car.
 
Fig.1 illustrates the density pattern for a lift with a rated capacity of 16 persons (rated load 1275 kg) with 16 persons present. It can be seen that the lift is not able accommodate this number of passengers, as the platform area is 2.9 m2, which would allow some 14 persons to be accommodated. Even with 14 persons present, the passengers would be in the intimate zone as shown in Table-2.
 
 
Fig.1: (16) person lift car occupied by (16) persons
 
Separation
Inter-Personal Distance
Characteristics
Intimate Distance
< 0.45 m
Body sounds, smell, heat all perceivable; sight distorted; very difficult to avoid contact.
Table-2
 

Number of passengers as per European Standard EN-81
 
The number of passengers shall be obtained by 2 methods:
 
Method#1:  from the formula,
 
Number of passengers = car rated load/75,
 
and the result rounded down to the nearest whole number; or
 
Method#2: from Table-3 which give the smaller value.
 
 
Number of passengers
Minimum available car area
m2
Number of passengers
Minimum available car area
m2
1
2
3
4
5
6
7
8
9
10
0,28
0,49
0,60
0,79
0,98
1,17
1,31
1,45
1,59
1,73
11
12
13
14
15
16
17
18
19
20
1,87
2,01
2,15
2,29
2,43
2,57
2,71
2,85
2,99
3,13
Beyond 20 passengers add 0,115 m2 for each extra passenger.
 
Table 3 - Number of passengers and minimum car available area
 
Notes:
 
  • It is recommended that a uniform figure of 0.2 m2 for each passenger be assumed (almost 5 persons/m2) when sizing a lift car in order to carry out a traffic design.
  • The average number of passengers carried per trip is an assumed value.
  • Industry practice assumes a car loading of 80% of rated capacity. Values less than 80% do not fully utilize the installation, and values above 80% quickly result in poor service times.
 
Calculation of Lifts Handling Capacity:
 
The handling capacity of a lift in passengers per hour is given by:
 
Cl = 3600P/ INT
 
Where:
 
Cl is the handling capacity (passengers/h),
P is the number of passengers in the car
INT is the interval between lift arrivals at the main floor (s).
 
The Actual Car Capacity:
 
Table-4 indicates that the actual car capacity figures are smaller than the rated car capacity suggested by dividing the rated load by 75.
 
Rated load
(kg)
(RL)
 
Max area
(m2)
(CA)
 
Rated capacity
(persons)
(CC)
 
Actual capacity
(persons)
(AC)
 
Design capacity
(persons)
(DC)
 
Capacity factor
(%)
(CF)
 
Actual load
(kg)
(AL)
320
0.95
4
4.5
3.6
90
338
450
1.30
6
6.2
5.0
82
465
630
1.66
8
7.9
6.3
79
593
800
2.00
10
9.5
7.6
76
713
1000
2.40
13
11.4
9.1
70
855
1275
2.90
16
13.8
11.0
69
1035
1600
3.56
21
16.9
13.5
64
1268
1800
3.92
24
18.6
14.9
62
1395
2000
4.20
26
20.0
16.0
62
1500
2500
5.00
33
23.8
19.0
58
1785
Table-4: Car loading and car capacity
 
Notes to Table-4:
 
  • Figures are rounded.
  • Rated load (RL) values, in kg, taken from ISO 4190–1.
  • Maximum area values, in m2, taken from EN81, Table 1.1.
  • Rated Car Capacity (CC) calculated by dividing the value for RL by 75 as EN81, Clause 8.2.3.
  • Actual Car Capacity (AC) calculated by dividing the value for maximum car platform area (CA) by 0.21.
  • Design Car Capacity (DC) calculated as 80% of actual car capacity (AC).
  • Capacity factor (CF), in per cent, calculated by dividing Actual Car Capacity (AC) by Rated Car Capacity (CC).
  • Actual load (AL), in kg, calculated by multiplying Actual Car Capacity (AC) by 75.
 

 

Comparison between Lifts and Escalators


 
The comparison between lifts and escalators can be summarized in the following table:
 
 
lifts
stairs and escalators
 
Efficiency measure
waiting time for a lift
The walking time (and walking effort) for stairs and escalators.
usage
lifts are used for “long distance” travel over a large number of floors
Stairs or escalators are used for travel over a small number of floors.
The use of escalators is mainly inhibited by the length of time travelling.
Examples of usage
Mid and High rise buildings such as big office buildings.
Low rise buildings, such as shopping centers, sports complexes, conference and exhibition centers, railway stations, airports, hospitals, etc.
Mid and High rise buildings in the following cases:
if there are lower trading floors
if there are car parks under the main terminal
where double decker lifts are installed, escalators can be used for access to the two lobby levels
 
 
Table-5 provides guidance on stair usage as per floors travelled.
 
Floors travelled
Usage up
Usage down
1
80%
90%
2
50%
80%
3
20%
50%
4
10%
20%
5
5%
5%
6
0%
0%
Table-5: Stair usage
 
Table-6 offers some guidance to the division of passengers between lifts and escalators in offices as per floors travelled.
 
Floors travelled
Escalator
Lift
1
90%
10%
2
75%
25%
3
50%
50%
4
25%
75%
5
10%
90%
Table-6: Lifts and escalators: division of traffic
 
Note:
  • The provision of well positioned stairs and escalators can considerably lessen the demands made on the lifts. Designers must take these factors into account.
 

 
 
Comparison of “Handling” Capacities


 
It might now be interesting to compare the “handling” capacities of the various building elements in persons/minute based on the following conditions:
 
  1. Considering all elements to be 1.0 m wide,
  2. All elements are assumed to be operating at their full flow design density levels, which is the optimal flow level.
  3. The values given are rounded for convenience, and apply to average groups of people and facilities.
 
Table-7 indicates the Comparison of handling capacities in persons/minute of the various building elements in persons/minute.
 
Circulatory mode
Element
Handling capacity
persons/minute
Density (persons/m2)
Horizontal
Corridor
84
1.4
Horizontal
Portal
60
 
1.4
Horizontal
Walkway
45
1.5
Incline
Stairs
60
2.0
Incline
Ramp
45
1.5
Incline
Escalator
75
2.5
Vertical
Lift
50*
5.0
* Passengers constrained by car walls.
Table-7
 

 
 
Fourth: Location And Arrangement Of Transportation Facilities


 
The location and arrangement of the passive circulation elements (corridors, portals) and the active circulation elements (passenger conveyors, escalators and lifts), should take account of:
  1. The location of entrances and stairs,
  2. The location of lifts and escalators,
  3. The distribution of the occupants in the building.
 
The main principles to bear in mind when selecting the Location and arrangement of transportation facilities are:
  1. To minimize the movements of people,
  2. To minimize the movements of goods,
  3. To prevent clashes between people and goods,
  4. To prevent bottlenecks.
 
The (3) possible Locations of transportation facilities inside a building are as follows:
 
Ideal Location
Good Location
Fair Location
all circulation activities should be centralized in a main core of a building
the main lobby is close to the main entrance
Main lobby some distance into the building. occupants and visitors will have a long walk to reach the transportation facilities
 
Notes:
 
  • It may be better for occupants to walk to the center of a building to access stairs and lifts, since their usage during the day may outweigh the comparative inconvenience during arrival and departure.
  • Generally the maximum distance to a lift or stair from an occupant’s work place should not exceed 60m with a distance of less than 45 m being preferred.
  • Emergency escape routes are usually closer, but do not necessarily form part of the normally used circulatory routes.
 

 
A- Location and Arrangement of Stairs and Escalators

 
 
There are several standard escalator arrangements, as shown in Fig.2.
 
  1. Parallel arrangement,
  2. Cross-over arrangement,
  3. Walk Round arrangement: this arrangement is typical of a shop as it allows the shop to deliberately lengthen the circulation route to pass goods for sale. This configuration also takes up less space.
 
 
 

Fig.2: Escalator configurations; (a) parallel, (b) cross-over, (c) walk Round
 
 
Recommendations for ideal Location and arrangement of Stairs and Escalators
 
  • Where possible, stairs and escalators should not lead directly off corridors, but should be accessed from landing and lobby areas, where people may wait without obstructing a circulation route. Thus the vertical and horizontal modes of circulation can be allowed to merge smoothly.
  • If it is the intention to encourage the use of stairs for short journeys to/from adjacent floors (inter-floor movement), then the stairs should be clearly visible, adequately signed and reached before entering the lift lobby.
  • The location of escalators should observe the same recommendations as those for the location of stairways. However, it should be noted that escalators occupy a larger footprint than stairs in order to accommodate their inclination, structure and equipment spaces.
  • It is particularly important that the boarding and alighting areas adjacent to an escalator are not part of another circulation route. This will provide a safe area for passengers to board and alight.
  • Escalators are typically used for short range movement between adjacent floors (the deep underground railway systems excepted). They are found in offices between principal levels, in shops between trading floors, in shopping centers between malls and elsewhere, such as railway stations, hospitals, museums, etc. They are usually sited in an obvious circulation path making it easy for pedestrians to board them.
 

 
B- Location and Arrangement of Lifts

  

 
The preferred arrangements from BS-5655: Part 6 of (2) to (4) lifts arranged side by side are given in Fig.3 and for (2) to (8) lifts arranged opposite each other are shown in Fig.4.
Note all the lobbies, indicated (L), have separate waiting areas with no through circulation.
 

 
 
Fig.3: preferred arrangements for lift cars: side by side (or in line)
 
Fig.4: Preferred arrangement for lift cars: facing
 
 
Recommendations for ideal Location and arrangement of Lifts
 
  • Lifts should always be placed together whenever possible, rather than distributed around a building. This arrangement will help to provide a better service (shorter intervals), mitigate the failure of one car (availability of an adjacent car or cars) and lead to improved traffic control (group systems).
  • Lift lobbies should preferably not be part of a through circulation route, either to other lifts, or other areas in the building. Lobbies should be provided that are dedicated to passengers waiting for the lifts.
  • Eight lifts are the maximum number which it is considered possible to present to waiting passengers, especially if the lifts are large (<26 person). This constraint allows passengers to ascertain the arrival of a lift easily (from the landing lantern and gong signals), walk across the lobby and enter the lift before the doors start to close.
  • The distance across a lobby is important. If the lobby is too large, passengers have too far to walk and the closure of the car doors has to be delayed (increasing the lobby door dwell time) to accommodate the increased walking time. BS ISO 4190–1:1999 gives some guidance as in below Table:
 
Building type
the landing depth (measured in the same direction as the depth of the car)
1- residential buildings
at least equal to the depth (d1) of the deepest car
2- office buildings:
 
- where lifts are located side by side
at least equal to 1.5×d1 and not less than 2.4 m
- where lifts are arranged face to face
at least equal to the sum of the depths of two facing cars, but not more than 4.5 m
 
 
The ideal lobby size would be one which could accommodate one full car load of passengers waiting and permit the simultaneous disembarkation of one full car load of arriving passengers.
 
Example#1:
 
Suppose there are four 21 person lifts arranged in a facing (2×2) configuration. What distance across the lobby would be appropriate given the car width is 2100 mm and the car depth is 1600 mm? The cars occupy a 6.0 m length of lobby (along the front of the cars).
 
Solution:
 
Case#1: Assume that a 21 person car can accommodate 21 persons.
 
When one of the cars in the group of four arrives, it will disembark 21 persons. Thus for these passengers to be accommodated at the dense level of occupancy of 2.0 persons/m2 in the lobby, an area of 10.5 m2 = 21 /2 would be required.
 
If it is assumed that there are 21 persons waiting to board, then they will require a further area of 10.5 m2.
 
Hence a total of 21 m2 is required.
 
As the lobby length is 6.0 m, then a width of 3.5 m is indicated, which is slightly larger than the ISO recommendation of the sum of the depths of two facing cars, ie: 3.2 m.
 
Case#2: Industry practice assumes a car loading of 80% of rated capacity
 
As a 21 person car will generally only be filled to an average occupancy of 80% of its rated load ie: 17 persons,
Thus for these passengers to be accommodated at the dense level of occupancy of 2.0 persons/m2 in the lobby, an area of 8.5 m2 = 17 /2 would be required.
 
If it is assumed that there are 17 persons waiting to board, then they will require a further area of 8.5 m2.
 
Hence a total of 19 m2 is required.
 
As the lobby length is 6.0 m, then a width of 3.2 m would probably be sufficient which is equal to the ISO recommendation of the sum of the depths of two facing cars, ie: 3.2 m.
 

 
In the next article, we will start explaining the Traffic Design Calculations. Please, keep following.

The previous and related articles are listed in below table:

Subject Of Previous Article
Article
Applicable Standards and Codes Used In This Course,
The Need for Lifts,
The Efficient Elevator Design Solution
Parts of Elevator System Design Process
Overview of Elevator Design and Supply Chain Process.
 
The Concept of Traffic Planning,
The (4) Methods of Traffic Design Calculations,
Principles of Interior Building Circulation:
A- Efficiency of Interior Circulation
 
B- Human Factors
 
C- Circulation and Handling Capacity Factors:
Corridor handling capacity,
Portal handling capacity,
Stairway handling capacity,
Escalator handling capacity,
 
 

  


 

 

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