1. Fundamental Considerations:
One of the many decisions that must be made by the designer of a multi storey building is the selection of vertical transportation equipment that is passenger, service and freight elevators (and escalators). The quality of elevator service is an important factor in the tenants' choice of space in competing buildings. Although the final decision as to the type of equipment rests with the architect, the factors affecting it are so numerous that the building designer should consult with an elevator expert. This service available from the consultants and the major manufacturers of elevators should be availed. One of the purposes of this book is to familiarize the architect and building engineers to make preliminary design decisions and interact effectively with consultants / manufacturers.
When considering traffic design of a new building the major building dimensions must be known. Unfortunately it is often the case that the architect responsible for the building conception will have fixed the building core limiting the space available for the lift system or even will have defined the number of shafts, their dimensions and travel. This removes one very important degree of freedom from the lift traffic designer. The total flow of traffic coming into the building, vertical movement and those going out the elevator decides the core efficiency of any building and hence it is essential that the architect consults the lift designer during conceptual finalization of any building.
Ideal performance of an elevator installation will provide minimum waiting time for a car at any floor, comfortable acceleration and deceleration; jerk free stopping, rapid transportation, smooth vibration free ride and accurate leveling at landings irrespective of load conditions in the car. The elevators must also provide smooth, quick, quiet and safe door operating system. Comfortable lighting, easy operation of car and landing buttons, floor level indicators know our position inside the building, annunciators to announce arrival of cars, safe operation of all mechanical equipment, provide pleasant elevator use and experience.
Above all, the passenger safety is utmost important even under failure of any single component in any part of the whole elevator system and the failure is detectable by the service mechanic so that it gets fixed before another failure. Combination of two undetected failures may result in major safety issue. Elevator companies with strong design background ensure safety of the passengers by conducting design reviews and failure mode and effect analysis (FMEA) during design of equipment. In addition to passenger satisfaction performance and service conditions, elevators also impact the architectural beauty of the building. The finish of cars and hoist-way door and other equipment have to gel with the architectural beauty of the building. Integration of elevator hoist-way spaces into the building and design of elevator lobby are also utmost important while selecting the finishes required in the elevator exteriors.
The elevators are covered by strict manufacturing and installation codes.
Many states in India have their own elevator codes guided by the bureau of Indian standards for elevators. There are codes related to fire safety, emergency evacuation, emergency power, handicapped elevators etc. Like most large industries, the elevator industry is self-regulating and standardized. Elevator company representatives are normally knowledgeable about all the codes and standards in force but this may not relieve the architect engineer of legal responsibility for the design. Therefore, it is strongly recommended that in the preliminary planning stage all pertinent regulations concerning vertical transportation be acquired, reviewed and understood.
Before any thought is given to the elevators in a building, a thorough and detailed study must be made of how people will arrive at the building, the building's occupancy and movement inside the building. Basic factors for determining the elevators for a building, the number of occupants in a building, the floor wise distribution of population, the arrival and departure rates at the lobby, the door performance namely the opening, closing and waiting time etc. are required to be estimated. Also determination of elevators depend upon the type of building namely residential, office, commercial, hotels, schools etc. The actual use of the building is beyond the control of the architect or an elevator engineer as most of the factors are based on assumptions. Past experience and surveys of similar existing buildings can help confirm these estimates.
It is always advisable to make the conservative estimates as it would be difficult and very expensive to make changes in the elevator size, speed or number of elevators.
In many cases it would not be possible to alter anything due to lack of space. The entire building will lose its charm if there are long waiting lines near the elevators and if it takes considerable time for the residents to move from one floor to the other.
The National building code of India prescribes provision of elevators for buildings 15m or more in height.
2. Some General Considerations:
2.1. Planning arrival of passengers in lobby:
Initially the pedestrian movement planning considering the location of lifts, the entry and exit points, size f the lobby for a given number of elevators of specific capacity, Space for queuing have to be planned. Elevators must be placed, arranged and designed to provide the most cost effective performance. Unsatisfactory pedestrian movement planning can damage a building's reputation and cause loss in productivity for its occupants.
2.2 Lighting:
The interior of an elevator car should car should be well lit and the lights arranged so that they cannot be turned off by unauthorized persons. The EN-81 (Aug 2014) standard requires higher lighting levels in both the lift car and shaft. In car lighting should provide illumination of 100 lux (was 50 lux) with emergency illumination of 5 lux for one hour ( was 1W for one hour). Lighting should be placed at a height of 1m in the center of the car close to emergency push buttons. Inaccuracy in floor level accuracy can cause possible tripping hazard which can aggravate due to poor lighting.
2.3 Grouping of Elevators:
As a general rule, if elevator service is essential to the building operation, two elevators should be considered as minimum equipment in vertical transportation. With a single car installation, a passenger who misses the elevator has to wait till it makes a complete round trip. Any elevator requires periodic servicing and replacement of wearing parts. During that time, with a single car, one would go without service. Such a situation can cause utmost discomfort to all including sick and elderly. If a building requires more than one passenger elevator, it is recommended to group the elevators with two or more elevators in a group, owing to technological advances of the operating system, the wait time could be substantially reduced and one can board the earliest arrived car. The maximum number of elevators in a group should not exceed eight elevators due to complexity of the operating logic and non-availability of good operating system.
2.3.1. Two Car Groupings:
for a two car group, side by side arrangement is the best. Passengers face both the cars and react immediately to an arriving car. Two cars facing each other is an acceptable alternative. In case of cars adjacent to each other, one can have single riser configuration, meaning common hall buttons, thus savings in one set of hall buttons. Also it would help having a common machine room so that inter connections between the elevator controllers become easy. Locating the elevators separately should be avoided. Separation of elevators at two different locations tends to destroy the group operation. The type of door may influence the choice. With center opening doors, adjacent cars may be preferable as it gives a balanced appearance. With two speed or single slide door, unequal space between the two elevator entrances may make the elevator opposite to each other configuration more preferable.
2.3.2. Three Car Grouping:
The arrangement of three cars in a row is preferable or two cars and one opposite is acceptable. Again, type of doors may influence the choice of location as explained for two car group.
2.3.3. Four Car Grouping:
Four elevator grouping are common in large busy buildings. Two opposite two is the most efficient option. All cars in a row arrangement increases the distance between the hall button and the last car in the row. With larger cars, the distance is appreciable considering the waiting population at the lobby.
2.3.4. Six Car Grouping:
Six cars, three opposite three is the most preferred arrangement. The waiting passenger can see all the elevators from his place and also can access all the cars easily. The lobby waiting time for elevators should be appropriately set to allow passengers to reach the elevators. Groups of six car elevators are very often found in large multi storied buildings.
2.3.5. Eight Car Grouping:
This is the largest group of elevators found in large buildings with four opposite to four being the most popular and practical arrangement. The main lobby must have opening at both ends so that the leaving passengers do not walk through the population due to other arriving cars.
2.3.6.Serving Floors:
All elevators in a group should serve the same floors. If for example, only one car out of a three car group serves the basement, people wishing to go to the basement from an upper floor have only one chance out of three. In such cases, it would serve better, if an additional elevator is used between the basements and lobby floor.
3. Arrangement of Lifts:
The lifts should be easily accessible from all entrances to the building. For maximum efficiency, they should be grouped near the center of the building. It is preferable not to have all the lifts out in straight line and, if possible, not more than three lifts should be arranged in this manner. It has to be kept in mind that the corridor should be wide enough to allow sufficient space for the waiting passengers as well as for through passengers. The ideal arrangement of the lifts depends upon the particular layout of the respective building and should be determined in every individual case.
3.1. Passenger Lifts:
3.1.1. Low And Medium Class Flats:
Where a lift is arranged to serve two, three or four flats per floor, the lift may be placed adjoining a staircase, with the lift entrances serving direct on to the landings. Where the lift is to serve a considerable number of flats having access to balconies o corridors, it may be conveniently placed in a well ventilated tower adjoining the building.
3.1.2. Office Buildings, Hotels, and High class flats:
It is advisable to have at least two lifts side by side at the main entrance and one lift each at different sections of the building for intercommunication. When two lifts are installed side by side, the machine room shall be suitably planned with sufficient space for housing the machine equipment. The positioning of lifts side by side gives the following advantages:
All machines and switch gear may be housed in one machine room.
The lifts can be inter connected more conveniently from an installation point of view, and
Greater convenience in service owing to the landing openings and each floor being adjacent.
3.1.3. Shops and Departmental Stores:
Lifts in shops and stores should be situated so as to secure convenient and easy access at each floor.
3.1.4. For Buildings with more than 12 Floors:
It is recommended to have provision of 1 stretcher / service lift in addition to the passenger lifts. Where passenger and service lifts are provided in one lobby it is recommended to have group control for all the lifts.
4. Goods Lifts:
The location of lifts in factories, warehouses and similar buildings should be planned to suit the progressive movement of goods throughout the building, having regard to the nature of position of the loading platforms, railway sidings, etc. The placing of lift in a fume or dust laden atmosphere or where it may be exposed to extreme temperatures, should be avoided wherever possible. Where it is impossible to avoid installing a lift in an adverse atmosphere, the electrical equipment should be of suitable design and construction to meet the environmental conditions involved. Normally goods lifts have lower speeds than passenger lifts for the same travel because traffic conditions are less demanding, and more time is required for loading and unloading. As loads for goods lifts increase in size and weight, so the operation of loading and unloading becomes more difficult. Therefore, it is usual to require greater accuracy of leveling as the capacity of the goods lift increases.
A large capacity goods lift at high speed is often a very uneconomical preposition. The inherent high cost is enhanced due to the very small demand for such equipment, much of which is custom made. The high capital cost of the lift, building work and electrical supply equipment usually shows a much smaller return as an investment than more normal sizes of lifts
5. Hospital Bed Lifts:
Hospital bed lifts should be situated conveniently near the ward and operating theatre entrances. There shall be sufficient space near the landing door for easy movement of stretcher. It is convenient to place the passenger lifts in a hospital, near the staircases.
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