Vertical Transportation Design and Traffic Calculations – Part Three

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.
We explained the first principle in above article. Today we will continue explaining other Principles of Interior Building Circulation.

Principles of Interior Building Circulation

   Second: Human Factors

A lift system has to be acceptable to the travelling passengers by satisfying some human factors or demands which are:
  1. Passenger s’ body Constraints,
  2. Passenger s’ satisfaction Constraints.

1- Passenger s’ body Constraints

The body constraints limit the manner in which a passenger may use the lift /escalator for vertical transportation, these constraints includes the following:
  1. The effects of sudden movement on the body (Acceleration or deceleration movement),
  2. Human physical dimensions,
  3. Human personal space,
  4. Allowable Personal Separation Distances/Zones,
  5. Passenger s’ body Constraints as per European Standard EN-81.


A- The effects of sudden movement on the body (Acceleration or deceleration movement)
  • To reach a certain floor, the passenger will sense a sudden movement of the lift, and then he will sense an increasing in the velocity rate of the lift which is called the acceleration and before reaching the assigned floor a deceleration (decreasing in the velocity rate of the lift) occurred till final stop.
  • The effects of sudden movement (Acceleration or deceleration) on the passengers’ body may give the passengers an uncomfortable trip experience and it will affect the passengers’ desire to use this lift again which will affect the interior circulation in the building.
  • The effect of Acceleration or deceleration movement on a passenger depends on the passenger s’ age, physical and mental health, and whether the passenger is prepared for the experience of a sudden movement.
  • It is known, by experience, the values of acceleration or deceleration which have been found to be generally acceptable, when riding in a lift to be as follows:
  1. acceleration/deceleration (rate of change of velocity) should be limited to about 1.5 m/s2,
  2. The values of jerk (rate of change of acceleration) to 2.0 m/s3.
As shown in Fig.1, Ideal acceleration, velocity and distance travelled curves for a single floor jump is as follows:
Fig.1: Ideal acceleration, velocity and distance travelled curves for a single floor jump
(a) Acceleration profile: maximum jerk 2.0 m/s3 and maximum acceleration 1.5 m/s2.
(b) Velocity profile: maximum speed 1.5 m/s.
(c) Distance travelled: total distance 3.0 m.
  • There is no limit to the velocity at which a passenger may travel in an enclosed lift car, as speed is not noticeable to the passenger.
  • It is the jerk values which cause the most discomfort. If the value of jerk is allowed to exceed 2 m/s3 for any length of time (10 seconds), discomfort will be experienced.
  • Whereas velocity and acceleration/deceleration can be specified and controlled in drive systems, jerk cannot. Constant values of jerk require that the acceleration/deceleration increase/decrease at a constant rate and this is not always possible.

B- Human Physical Dimensions
It is recommended that the body template be considered as an ellipse of dimensions 600 mm by 450 mm and occupying 0.21 m2 (see Fig-2). This is a maximum value and can be used where pedestrians are not standing in a confined space.

Fig.2: Typical Occupancy Ellipse of a Person

C- Human Personal Space
Human personal space is measured by a ‘buffer zone’ around each individual person. The size of the buffer zone varies according to an individual’s culture, age, status, sex, physical and mental handicaps. It will be as per below table-1:
Personal Buffer Zone
Diameter Circle
individual female
individual male
Table-1: size of the buffer zone
The buffer zone factors must be borne in mind when designing pedestrian waiting areas.
Also, recommended densities, when considering bulk queues (i.e. people waiting for an event) in waiting areas, are given in Table-2.
Level of comfort
Density (person/m2)
Allows individuals to walk more or less where they want to go or stand without any interference from other individuals.
Allows individuals to walk, with some deviations necessary, where they want to go and for individuals to stand without any interference from other individuals.
Individuals who are walking must now take care not to collide with other persons and persons waiting are aware that other individuals are present.
It is only possible to walk at a shuffle and with care at the average rate of the crowd. There is no or little chance of contraflow. Individuals waiting are very aware of other individuals.
Very crowded
Walking is almost impossible. Individuals waiting are unhappy to be so close to other individuals. This density is only possible where persons are placed in a confined space, such as a lift car or a rapid transit train.
*Possible only in confined spaces
Table-2: Recommended densities of people in bulk queues
Fig-3 gives an illustration of the density of occupation in waiting areas.
Fig-3: Illustration of the Density of Occupation in Waiting Areas
Notes to table-2:
  • When considering linear queues (i.e. people ‘waiting in a line’ for a service) assume 2 persons per meter length of space.
  • If a barrier is used, a queue can be restrained to the barrier width which should be set to no less than 600 mm.
  • For unrestrained queues assume 1.5 m width.


D- Allowable Personal Separation Distances/Zones
Allowable Separation distances between persons are based on the sensory shifts of sight, smell, hearing, touch and thermal receptivity and can be classified into different zones as per table-3.
Inter-Personal Distance
Public Distance (Far)
> 7.5 m
Little sensory involvement; oral communication loud, exaggerated and stylized (theatrical).
Public Distance (Near)
3.6-7.5 m
Oral communication less loud, less exaggerated, still stylized; general facial expressions detectable (frown, smile).
Social Distance (Far)
Aspects of personal grooming visible; possible to pass objects.
Social Distance (Near)
Considerable facial details visible; ease of passing objects; not possible to seize an individual.
Personal Distance (Far)
Fine details of complexion, teeth, eyes, etc. visible; occasional detection of body perfumes; possible to seize a person.
Personal Distance (Near)
0.45-0.75 m
Details of cleanliness discernable; occasional detection of body perfumes; bodily contact avoidable but easily possible.
Intimate Distance
< 0.45 m
Body sounds, smell, heat all perceivable; sight distorted; very difficult to avoid contact.
Table-3: Separation zones

Fig.4: Seven Separation Zones

The above seven Separation zones are illustrated in Fig-4. The definitions of these Separation zones are as follows:
  • The public distance classification is sometimes called the flight zone to indicate that an individual can take evasive or defensive action.
  • The social distance (far) represents a zone of potential vulnerability (the en garde of sword fighting) and is the distance used for formal meetings in contrast to the social distance (near) used for casual meetings.
  • The personal distance (far) is defined as an individual’s circle of trust and can be considered the interpersonal spacing found in a spacious waiting area.
  • The personal distance (near) is commonly encountered in denser waiting areas and queuing situations. Clearly, crowding occurs with the intimate distance classification leading to the “touching” situation found when travelling in a lift car.

E- Passenger s’ body Constraints as per European Standard EN-81
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.
Number of passengers as per European Standard EN-81
The number of passengers shall be obtained from:
  1. Either, from the formula, Number of passengers = car rated load/75, and the result rounded down to the nearest whole number; or
  2. Table-4 which give the smaller value.
Number of passengers
Minimum available car area m2
Number of passengers
Minimum available car area m2
Beyond 20 passengers add 0,115 m2 for each extra passenger.
Table 4 - Number of passengers and minimum car available area
  • It is recommended that a uniform figure of 0.2 m2 for each passenger be assumed 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.


2- Passenger s’ satisfaction Constraints

A passenger expects a good service from a lift system and the owner expects a good interior circulation inside the building. This can be done by fulfilling the following satisfaction Constraints:
  1. Safety of the Lift System,
  2. Passenger Waiting Time,
  3. The Car Travelling Time.

A- Safety of the Lift System
The safety requirements are covered by the safety rules assigned at national and worldwide standards and codes. The safety requirement is most important so that passengers may feel confident about the way they are handled since no one will use a lift that has a safety issues. Therefore, it is preferable that the owner of the building to announce the lift passengers about the lifts’ safety certificates issued by a third party and according to which code to encourage the passengers to use the lifts and getting an efficient Interior Circulation inside the Building.

B- Passenger Waiting Time
An individual passenger expects a different grade of service at different times of the day and at different locations. For example, an office worker will not be too annoyed if delayed when travelling up a building to work, but will become very annoyed if delays occur when leaving at night. In contrast, the same office worker would not expect the same grade of service from a lift in a residential block. In general, the average waiting time in an office block should not exceed 30s and in the residential block it should not exceed 60 s.

C- The Car Travelling Time
Here the passenger is dependent on the fellow passengers in the car and other passengers on the landings making calls. A passenger travelling high up a building becomes non-satisfied of stops after about 90 s of travel. Again the non-satisfaction level depends on whether the passenger is travelling in company of friends or colleagues and on the other passengers’ behavior. This constraint has been summed up by Strakosch (1967) as “a person will not be required to ride a car longer than a reasonable time”.

In the next article, we will continue explaining other Principles of Interior Building Circulation. Please, keep following.

The previous and related articles are listed in below table

Subject Of Previous 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

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