Elevators PDF

BUILDING UTILITIES 2 VERTICAL TRANSPORTATION SYSTEMS Lecture 1 ENDURING VALUES OF ARCHITECTURE FIRMITAS or SURVIVAL (to protect) UTILITAS or GOOD LIFE (to nurture) VENUSTAS or ART (to transform) CONTEMPORARY VALUES  Human (functional, social, physical, physiological, psyc...

BUILDING UTILITIES 2 VERTICAL TRANSPORTATION SYSTEMS Lecture 1 ENDURING VALUES OF ARCHITECTURE FIRMITAS or SURVIVAL (to protect) UTILITAS or GOOD LIFE (to nurture) VENUSTAS or ART (to transform) CONTEMPORARY VALUES  Human (functional, social, physical, physiological, psychological)  Environmental (site, climate, context, resources, waste)  Cultural (historical, institutional, political, legal)  Technological (materials, systems, processes)  Temporal (growth, change, permanence)  Economic (finance, construction, operations, maintenance, energy)  Aesthetic ( form, space, color, meaning)  Safety (structural, fire, chemical, personal, criminal)  ELEMENTS OF BUILDING  Building Systems 1. Foundation/Subgrade (SITE) 2. Superstructure (STRUCTURE) 3. Exterior Envelope (SKIN) 4. Interior Partitions (SPACE PLAN) 5. Mechanical Systems (SERVICES) 6. Furnishings (STUFF)  Cost  Lifetimes/Durability  Performance Requirements  Integration of Building Systems 1. Spatial Performance 2. Thermal Performance 3. Air Quality 4. Acoustical Performance 5. Visual Performance 6. Building Integrity INTRODUCTION to LECTURE  One of the more important decisions to be made in the design of a multi-story building is the selection of the vertical transportation equipment – that is, the passenger service, the freight elevator, the escalator and the ramp.  They have different dimensions and uses according to building type & number of users in it.  The quality of these equipment is an important factor in a tenant’s choice of space in competing buildings. ELEVATORS  An elevator ,or lift, is a type of vertical transport equipment that efficiently moves people or goods between floors (levels, decks) of a building, vessel or other structures.  Elevators are generally powered by electric motors that either drive traction cables or counterweight systems like a hoist, or pump hydraulic fluid to raise a cylindrical piston like a jack. IDEAL PERFORMANCE OF AN ELEVATOR INSTALLATION Provide minimum waiting time for a car at any floor level Comfortable acceleration Rapid transportation Smooth, rapid braking Accurate automatic leveling at all stops Provide quick, quiet power operation of doors Good floor and travel direction indication, both in the cars and at landings Easily operated car and landing call buttons (or other devices) Smooth, quiet, and safe operation of all mechanical equipment for all conditions of loading Comfortable lighting Reliable emergency and security equipment Generally pleasant car atmosphere Design of cars, shaftway doors, and elevator lobbies must have architectural unity with the building TYPES OF ELEVATORS –According to Hoist Mechanism. –According to Building Height. –According to Building Type. –According to Elevator Location. –According to Special Uses. TYPES OF ELEVATORS - According to HOIST MECHANISM  Hydraulic Elevators  Traction Elevators  Climbing elevator  Pneumatic Elevators Hydraulic Elevator (Push Elevators) – It consists of a car attached to the top of an hydraulic jack, similar to the jack used to lift cars in a service station. – The hydraulic jack assembly normally extends below the lowest floor and is operated by a hydraulic pump and reservoir, both of which are located in a separate room adjacent to the elevator shaft. – The jack is located in a casing, and while it will resist damage from small amounts of water seepage, total inundation by floodwaters will usually result to contamination of the hydraulic oil and possible damage to the cylinders and seals of the jack. – The hydraulic pump and reservoir are located up to 2 floors above the jack. – Generally used in single-family residences A. Holed (Conventional) Hydraulic Elevators  They have a sheave that extends below the floor of the elevator pit, which accepts the retracting piston as the elevator descends.  Some configurations have a telescoping piston that collapses and requires a shallower hole below the pit.  Maximum travel distance is approximately 60 feet. B. Hole-less Hydraulic Elevators 1. Telescopic Hydraulic Elevators  The telescoping pistons are fixed at the base of the pit and do not require a sheave or hole below the pit and has 2 or 3 pieces of telescoping pistons.  Telescoping pistons allow up to 50 feet of travel distance. 2. Non-telescoping (single stage) Hydraulic Elevators It has one piston and only allows about 20 feet of travel distance. 3. Roped Hydraulic Elevators  They use a combination of ropes and a piston to move the elevator.  Maximum travel distance is about 60 feet. Traction Elevator (Pull Elevators) – The electric motor and most other equipment are normally located above the elevator shaft. – Some equipment, however, such as the counterweight roller guides, compensation cable and pulleys, and oil buffers, usually must be located at the bottom of the shaft. – Traction-type elevators are further classified according to elevator machines used: Gearless traction machine Geared traction machine GEARLESS TRACTION MACHINE Consists of a dc or ac motor, the shaft of which is directly connected to a brake wheel and driving sheave Absence of gears means that the motor must run at the same relatively low speed as the driving sheave Utilized for medium- and high-speed elevators, that is, 2.50 meters per second (m/s) and above. Motors range from 20 to 400hp For passenger service, with car capacities of 1000 to 2000 kgs Considered superior to a geared machine because it is more efficient, quieter in operation, requires less maintenance, and has longer life Generally chosen where the height (rise) is more than 76 meters and very smooth, high-speed operation is desired GEARED TRACTION MACHINE Consists of a dc or ac motor, has a worm and gear interposed between the driving motor and hoisting sheave The driving motor can either be a smaller unit rather than a large unit that a gearless installation would require Utilized for car speeds of up to 2.50 meters per second and a maximum rise of up to 100 meters. Machine-Room-Less Elevators They are typically traction elevators that do not have a dedicated machine room above the elevator shaft. This was made possible by the development and application of permanent magnet (PM) system technology in the lift motor that reduced the size of the motor by up to four times. The machine sits in the override space and the controls sit above the ceiling adjacent to the elevator shaft. Machine-room-less elevators are becoming more common; however, many maintenance departments do not like them due to the hassle of working on a ladder as opposed to within a room. Climbing elevator They hold their own power device on them, mostly electric or combustion engine. Climbing elevators are often used in work and construction areas. Pneumatic Elevators  Pneumatic elevators are raised and lowered by controlling air pressure in a chamber in which the elevator sits.  By simple principles of physics; the difference in air pressure above and beneath the vacuum elevator cab literally transports cab by air. It is the vacuum pumps or turbines that pull cab up to the next floor and the slow release of air pressure that floats cab down.  They are especially ideal for existing homes due to their compact design because excavating a pit and hoist way are not required. TYPES OF ELEVATORS - According to BUILDING HEIGHT A- Low-Rise buildings (1- 3 stories) Buildings up to about (1 to 3) stories typically use hydraulic elevators because of their lower initial cost B- Mid-Rise buildings (4 -11 stories) Buildings up to about (4 to 11) stories typically use Geared Traction Elevators C- High-Rise buildings (12 + stories) Buildings up to about 12+ stories typically use Gear-Less Traction Elevators TYPICAL DOUBLE-DECK ELEVATORS TYPES OF ELEVATORS - According to BUILDING TYPE Elevators will be classified according to building type to 6 main types as follows:  Hospital Elevators  Residential /Domestic Elevators  Agricultural Elevators  Industrial Elevators  Commercial Elevators  Parking buildings Elevators TYPES OF ELEVATORS - According to LOCATION Outdoor Elevators  Observation elevator puts the cab on the outside of the building. Traction lifting machine is placed behind the cab.  Glass-walled elevator cars allow passengers to view the cityscape or the building’s atrium as they travel.  By eliminating the hoist ways, the observation elevator also offers owners, architects and builders valuable space-saving advantages.  Incline Elevators are most often recognized as passenger elevators called ski lifts.  However, outdoor elevators that move cargo on an incline are generally constructed with a conveyor belt and most often seen when loading cargo on ships and some types of aircraft.  Outdoor elevators built on an incline can also be used to transport passengers or goods.  Slant elevator have been constructed in numerous locations where a building is built onto an inclined surface  The motive machine used varies with the angle of inclination  The car rides on inclined rails and is pulled up by a traction cable  Counterweighted either by a weight riding on another set of rails, in case of a single car, or by the weight of another car in a 2-car installation Platform Elevators  While it is possible to use platform elevators indoors they are generally classified as outdoor elevators because that is where they are most often used.  Platform elevators usually are not enclosed by having a have a fence or gate running around the perimeter to keep cargo from slipping off during transport.  Platform elevators usually use a system of pulleys as the working mechanism.  Outdoor elevators consisting of a platform are most often used at new construction sites but they can also be used for such things as elevating workmen renovating the façade of a building or washing windows on a high-rise.  Freight elevators are almost always outdoor elevators even though some smaller versions are designed for indoor use such as those used in warehouses.  They are most often extremely heavy-duty and can facilitate a great amount of weight.  This type of elevator can either be on an incline or vertical, but will most often be industrial grade to accommodate those heavy loads. In fact, the first type of elevator which comes to mind when thinking of outdoor elevators is actually freight elevators. KEY PERFORMANCE INDICATORS FOR FREIGHT ELEVATORS Size of load Type of load Method of loading Travel Type of doors Speed and capacity of cars LOAD CLASSIFICATIONS FOR FREIGHT ELEVATORS Class A. General Freight Loading by hand truck Single items may not exceed 25% of the car-rated load. The rated load is based on 50psf of net inside platform area. Class B. Motor Vehicle Loading The elevator cars will carry automobiles or automobile trucks. The rating is based on a load of 30psf of net inside platform area. Class C1. Industrial Truck Loading Truck carried Class C2. Industrial Truck Loading Truck not carried Class C3. Concentrated Loading No trucks used; increments greater than 25% rated capacity For Classes C1, C2, and C3, the rated load is based on 50psf. Elevator cars have automatic leveling. FREIGHT ELEVATOR DESCRIPTION Speeds are generally between 50 and 200 fpm (0.25 and 1.00 m/s) Uses a geared-type traction machine or a hydraulic unit Preferred system of control is collective, with a variable-voltage , dc supply, either unit multivoltage (UMV) or variable-voltage variable- frequency (VVVF) Accurate leveling is not essential Rougher ride is tolerable For low-rise installations, a hydraulic at speeds of up to unit is most often employed (rarely exceed 18 meters in height and operates at speed of 0.60 m/s) Accessories, such as generators, safety devices, and brakes are similar to those for passenger elevators Load ranges of up to 20,000 lbs are standard design items for general-purpose freight elevators. Units of 20,000 lbs and more require special safety devices. FREIGHT ELEVATOR DESCRIPTION Applicable to all types of commercial and industrial buildings. Must be provided with additional and adequate structural supports Uses a 2:1 roping arrangement Cars for freight service are normally built of heavy-gauge steel with multi-layer wooden floor The entire unit must be designed for hard service Guarded ceiling light fixtures are required Car gates slide vertically and are a minimum of 6ft high. Hoistway doors are normally vertical-lift, center-opening, manual or power- operated Both car gate and hoistway doors are counterweighted and open fully to give complete floor and head clearance Indoor elevators All elevators installed inside a building which usually need a hoist ways and pits. TYPES OF ELEVATORS - According to SPECIAL USES Elevators can be classified according to special use types as follows:  Handicap Elevators  Grain Elevators  Double-deck Elevators  Sky lobby Elevators  Limited Use/Limited Application (LU/LA) Elevators  HANDICAP ELEVATORS Residential Elevators and Chair Lifts – Low-speed, low-rise, limited-load units – Maximum size of 18sf, load of 1400 lbs, rise of 25ft and speed of 30fpm – Available in a range of installation designs; winding-drum units, roped hydraulics, and worm-and- screw units – Safety requirements are different from standard traction elevators STANDARD ELEVATOR LAYOUTS Arrangement (A): Car with side opening door and the counterweight is located at the back wall. Arrangement (B): Car with central opening door and the counterweight is located at the back wall. Arrangement (C): Car with side opening door and the counterweight is located at one side. Arrangement (D): Car with central opening door and the counterweight is located at one side. PRINCIPAL COMPONENTS OF AN ELEVATOR PRINCIPAL COMPONENTS OF AN ELEVATOR Car – A cage of some fire-resistant material supported on a structural frame, to the top member of which the lifting cables are fastened – Guided in its vertical travel in the shaft by guide shoes on the side members – Provided with safety doors, operating control equipment, floor-level indicators, illumination, emergency exits, and ventilation Cables – Ropes that are made of groups of steel wires designed to carry the weight of the car and its live load and are usually 1/2”or 5/8” in diameter each – They are used on traction type elevators and placed in parallel are 4 to 8 cables, depending on car speed and capacity, and fastened to the cross-head (top beam of the elevator) – Multiple ropes are used primarily to increase the traction area on the drive sheaves and also increase the elevator safety factor – Cables from the top of the car pass over a motor-driven cylindrical sheave at the traction machine and then downward to the counterweight  Elevator machines – Turn the sheave and lifts or lowers the car – Consist of a heavy structural frame on which are mounted the sheave and the driving motor, gears (if any), brakes, magnetic safety brakes, and other auxiliaries – In many existing installations, the driving motor receives its energy from a separate motor-generator (m-g) set which operates when that particular elevator is available for handling traffic. This m-g set is considered a part of the elevator machine and may be located some distance from it – A governor, which limits the car to safe speeds, is mounted on or near the elevator machine Control equipment – Usually divided into three groups: Drive (motion) control is concerned with the velocity, acceleration, braking, position determination, and leveling of the car, plus all aspects of door motion Operating control covers car door operation and functioning of car signals, including floor call buttons and all indicating devices Supervisory control is concerned with group operation of multiple-car installation  Counterweights – Made up of cut-steel plates stacked in a frame attached to the opposite ends of the cables to which the car is fastened – Guided in its travel up and down the shaft by 2 guide rails typically installed on the back wall off the shaft – Its weight equals that of an empty car plus 40% of the rated live load – Provides adequate traction at the sheave for car lifting, reduce size of traction machine, and reduce power demand and energy cost – Attached to the bottom of the counterweights and the car are compensation cables intended to compensate for the hoist rope weight Shaft or hoistway – Vertical passageway for the car and counterweights – On its sidewalls are the car guide rails and certain mechanical and electrical auxiliaries of the control apparatus – At the top is the structural platform on which the elevator machine rests.  Elevator machine room – Usually directly above the hoistway – Contains the traction machine and the motor-generator set that supplies energy to the elevator machine and control equipment Guide rails – Steel Tracks in the form of a “T” that run the length of the hoistway, round, or formed sections with guiding surfaces to guide and direct the course of travel of an elevator car and elevator counterweights and usually mounted to the sides of the hoistway. Elevator Pit – The bottom of the shaft where the car and counterweight buffers are located ELEVATOR ROPING and SHEAVE ARRANGEMENT The simplest method of arranging vertical travel of a car is to pass a rope over a sheave and counter-balance the weight of the car by a counterweight. Then by rotating the sheave, the car moves up or down and requires very little energy to do it. This is essentially the scheme that is used on a majority of high-speed passenger elevators. ELEVATOR ROPING and SHEAVE ARRANGEMENT When 4 or more supporting ropes merely pass over the sheave and connect directly to the counterweights, the lifting power is exerted by the sheave through the traction of the ropes in the parallel grooves on the sheave. This system is referred to as single-wrap traction elevator machine. This is only possible for small cars because the distance between the car and counterweight is limited. The function of the sheave S is merely that of a guide pulley; it is called deflector sheave. ELEVATOR ROPING and SHEAVE ARRANGEMENT The arrangement shown below is called double-wrap 1:1 roping. The extra wrap provides greater and reliable traction than the single-wrap arrangement and is used in many high- speed installation. ELEVATOR ROPING and SHEAVE ARRANGEMENT The 2:1 roping has a mechanical advantage of 2, that is the ropes move twice as fast as the car. This permits use of a high-speed, low- power traction machine. This arrangement is used for a wide variety of installations varying from medium-speed 2.50m/s to 3.50m/s gearless passenger elevators to low-speed , heavy-duty freight elevators. ELEVATOR ROPING and SHEAVE ARRANGEMENT The underslung roping arrangement permits the machine room to be located at the basement floor, reducing the height needed at the top of the building if the machine room were at the penthouse. This arrangement uses geared traction equipment with speed of up to 2.00 m/s. ELEVATOR DOORS The choice of the car and hoistway door affects the speed and quality of elevator service considerably. Doors for passenger elevators are power-operated and are synchronized with the leveling controls so that the doors are fully opened by the time a car comes to a complete stop at the landing. The closing time, however, varies with the type of door and the size of the opening. For safety reasons, the kinetic energy of an automatic door is limited to 7 ft-lbs and the closing pressure to 30 lbs. To provide the fastest closing within this energy limitation, a center- opening door is used. Also, to reduce passenger transfer time and avoid discomfort, a clear opening of 1.07 meters (3 ft-6 in.) is used in most commercial installations, which permits simultaneous loading and unloading without undue passenger contact. When an opening narrower than 36 inches is used, loading is delayed until unloading is complete, and the speed and quality of service are reduced. Such small doors are applicable only in residential or small, light- traffic buildings.  A two-speed door design is used where space conditions dictate or where a wide opening is required. The term two-speed reflects that the 2 halves of the door must travel at different speeds to complete their travel simultaneously. Doors can be equipped with an electronic sensing device that detects passengers in a wide area on the landing in front of the car door rather than only directly in the door’s path. These devices are useful where passengers cannot approach the entrance or cannot enter the car quickly , for example, riders with baggage or holding children, or people in wheelchair. All automatic elevators are required to have a safety edge device on the car doors that causes the car and hoistway doors , which operate in synchrony, to reopen when the safety edge device meets an obstruction. Single-slide door, 24 to 36 in. wide Standard commercial 42-in. center- for small commercial building or Opening door for office building use residential use Or 48- to 60-in. center opening for hospital or service car Two-speed, single-side Two-speed, center-opening 42-in. wide for general 60-in. wide for department and commercial use door store door for freight, passenger and non-automatic service  ELEVATOR CAR CONTROL The modern elevator control systems include a logic controller that takes the user’s input and translates it into meaningful actions. The logic controller's central processing unit (CPU) must be given at least three critical pieces of information, namely:  Where people want to go? ₋ comes directly from the users and the elevator controls must interface with user’s requests. In its simplest form, when the users desire to ride the elevator they press a button located in the elevator lobby.  Where each floor is? ₋ can often be determined by the addition of holes located on a long vertical tape inside the elevator shaft. The elevator car is equipped with a light or magnetic sensor that reads the number of and which holes are being passed by the elevator car as it ascends and descends.  Where the elevator car is? ₋ related to the elevator scheduling operations. When a user presses the ‘Up’ or ‘Down’ button outside the elevator car, the elevator should begin moving towards them. Logic controllers must have some way to determine in what order riders should be picked up and dropped off. ELEVATOR CAR CONTROL The main aims of the elevator control system are:  To bring the lift car to the correct floor.  To minimize travel time.  To maximize passenger comfort by providing a smooth ride.  To accelerate, decelerate and travel within safe speed limits. Simple Elevator Control System Inputs and Outputs Types of Elevator Control Systems Single Automatic operation  First automated system w/o single call button on each floor and single button for each floor inside car.  Called if no one is using it.  Passenger has exclusive use of the car until trip is complete. Collective control  Cars stop at each floor that registers a call irrespective of direction, hence the term collective; slow and annoying service, and as a result, this system is no longer used in new installations.  Selective collective operation  Most common, remembers and answers calls in one direction then reverses. When trip is complete, the car is programmed to return to a home landing. Group automatic operation For large buildings with many elevators which are controlled with programmable microprocessors to respond. Elevator Control System Components The elevator control system has a number of components that can basically be divided into the following:  Inputs A- Sensors B- Buttons C- Key controls D- System controls  Outputs A- Actuators. B- Bells C- Displays  Controllers Elevator Control Input System Components A. Sensors Magnetic and/or photo electric These pick up signals regarding the location of the car. This sensor is usually placed on the car itself and reads the position by counting the number of holes in the guide rail as they pass by in the photo-electric sensor or in the case of the magnetic sensor, the number of magnetic pulses. A. Sensors Infrared This is used to detect people entering or leaving the elevator. A. Sensors Weight Sensor or Overload Device This is placed on the car to warn the control system if the design load is exceeded. A. Sensors PVT (primary velocity transducer) Velocity of the drive sheave is sensed with this encoder. B. Buttons Hall Buttons These buttons are on a button panel on the outside of the elevator shafts and are used by potential passengers to call an elevator cab to the floor that the pressed summon button is located on. There are two hall buttons on each floor – one for up, another for down, except on the top floor where there is only down and on the bottom floor where there is only up. The controller interacts with these buttons by receiving press and release signals indicating the requested direction and floor number. It also sends light on/off signals to indicate the status of the buttons. B. Buttons Floor Request Buttons This particular elevator controller will be controlling elevator cabs that are in a building with 8 floors. Consequently, each cab has 8 floor request buttons labelled 1 through 8 that passengers can use to direct the elevator cabs to the floor that they would like to go to. These buttons are located on a button panel on the interior of each elevator cab. The controller interacts with these buttons by receiving pressed signals indicating the desired floor number and elevator cab which they were pressed from. It also sends light on/off signals to indicate the status of the buttons. B. Buttons Open/Close Door Button This button is on the interior button panel of each cab. A passenger can press this button to open the elevator doors or keep pressing it to keep them open, but only when the elevator cab is stopped at a floor. Some elevator systems also have a close door button, but this one does not. The controller interacts with this button by receiving a signal when it is pressed and when it is released. Both of these signals include the cab from which they came from. B. Buttons Emergency Stop Button This button is on the interior button panel of each cab. A passenger can press this button to stop the elevator no matter where it is in a shaft. The controller interacts with this button by receiving a signal from it that indicates that it was pressed, as well as the cab that it came from. B. Buttons Emergency Bell Button This button is on the interior button panel of each cab. A passenger can press this button to sound a bell to alert people outside of the elevator shaft that someone is trapped inside the elevator cab in case of a malfunction. The controller interacts with this button by receiving a signal from it that indicates that it was pressed. B. Buttons Registration Panel In destination control systems, the conventional hall call buttons (Up and Down arrows) located at the elevator lobby are replaced by the registration devices. Passengers register their destination floor through these registration devices at the lobby instead of in the elevator. The registration device will display the elevator that has been assigned for transporting the passenger. As the passenger has already registered the desired destination floor, there is no need to input the destination floor in the elevator. C. Key controls Key controls may only be activated by the proper keys, and their use is thus restricted to repair people, elevator operators or firemen. It is used in place of or in conjunction with a pushbutton to restrict access to a floor. Keypads and card readers are also available. Examples for these keys are as follows:  Fireman's service, phase II key switch.  An inspector's switch, which places the elevator in inspection mode (this may be situated on top of the elevator).  Manual up/down controls for elevator technicians, to be used in inspection mode, for example.  An independent service/exclusive mode Switch (also known as "Car Preference"), which will prevent the car from answering to hall calls and only arrive at floors selected via the panel. The door should stay open while parked on a floor. This mode may be used for temporarily transporting goods. The controller interacts with the switch by receiving a signal from it when it has been toggled to either AUTO or HOLD mode. AUTO is for normal operation; HOLD is to keep the elevator cab from moving and its doors from opening or closing.  Attendant service mode switch. Key controls D. System controls System controls are used to turn the elevator system on or off, system controls are only accessible from an elevator control room. They would typically be used quite infrequently – perhaps the system would be turned on early in the morning and turned off late at night, or turned off at the start of holidays and turned on once the next term begins. Elevator Control Output System Components A. Actuators Door Opening Device On top of each elevator cab is a door opening device. This device opens the inner door of the elevator cab and the outer door of the elevator shaft simultaneously at each floor. The controller interacts with the door opening device by sending signals to open or close the doors and by receiving signals when the doors have been completely opened or closed. The signals that the controller receives also indicate which cab they are coming from. A. Actuators Electric motor The elevator motor is responsible for moving an elevator cab up and down between floors. As this elevator system uses a roped mechanism, the elevator engine is connected to a sheave which the ropes are looped around. The controller interacts with the elevator engine by sending it a signal that specifies at which speed and in what direction the engine should be going in. A stop signal is simply constructed by setting the speed parameter of the signal to zero. A. Actuators Brakes There a few brake systems in a typical elevator system. These include the electromagnetic and mechanical brakes. The electromagnetic brakes activate automatically if there is a sudden loss of power or when the car is stationary. The mechanical brakes at the sheave itself also stop the car from moving when the car is inactive. B. Bells Emergency Bell Somewhere in the elevator system is an emergency bell that is used to alert people outside of the elevator system that someone is trapped inside an elevator cab. The controller interacts with the emergency bell by sending it a signal to ring. Load Bell Each cab has a load bell that is used to alert the passengers inside the cab that there is too much weight in it to operate it safely. The controller interacts with the load bell be sending it a signal to ring. C. Displays Car Position Display The interior of each elevator cab has a display that indicates to its passengers which floor the elevator cab is currently on. Some elevator systems have this floor number display on every floor outside of the elevator doors, but this system does not. The controller interacts with this display by sending a signal that tells it which floor number to display. Can be either analog (individual indicators for each floor) or digital ( a dot matrix or segmented LED that changes to indicate the floor level). C. Displays Car Direction Display The interior of each elevator cab has a display that indicates the current direction of an elevator cab; it is either up or down. The controller interacts with this display by sending it a signal that tells it which direction to display. Elevator Controller System Components Controllers The controller is a device which manages the visual monitoring, interactive command control and traffic analysis system to ensure the elevators are functioning efficiently. The primary function of the elevator controller is essentially to receive and process a variety of signals from several different components of a whole elevator system. It is able to send signals in response to the ones it receives in order to operate all of the other components in the system. This exchange of signals is how the elevator controller is able to keep the elevators running smoothly on a day-to-day basis. Controllers Ways the controller interacts with the other components of the elevator system:  Controls the speed of elevator engines in order to move elevator cabs up and down their respective shafts.  Queues and processes elevator summons and floor requests from passengers through the signals provided to it by several buttons.  Processes information sent to it by load sensors in order to ensure that the load of a cab never exceeds the safety limit.  Processes information sent to it by position marker sensors in order to keep track of where the elevator cabs are at all times, as well as their speed.  Provides feedback to passengers through the lights on some of the buttons and the floor number and direction displays in each cab.  Can sound alarm bells that are either invoked by trapped passengers or required to warn of excess load in a cab.  Controls the operation of the elevator doors of a cab through communication with door opening devices.  Types of Elevator Controllers Relay based controller (electromechanical switching) A relay is a very dependable device consisting of an electromagnet that opens and closes contacts, routing the logic to various circuits. A simple elevator with a few stops and manual door operation can be served well by a relay controller. Relays can also be used for more complex elevators, and in fact were until the 1980's. However, the number of relays required can make it difficult to troubleshoot should there ever be a problem. The following applications may be recommended as suitable for controllers using electromagnetic relay technology:  Single lifts only.  Drive speed up to 1 m/s.  Passenger lifts in low traffic and usage situations in low-rise buildings, i.e. not more than three stories (e.g. residential buildings, very small hotels, nursing homes).  Goods, bullion lifts in low-rise commercial buildings (e.g. offices, hotels, hospitals). Solid-State Logic Technology It includes both discreet transistors circuits and integrated circuit boards. It gives improved reliability, lower power consumption and easy fault diagnosis than electromagnetic relay technology. The following applications are recommended as suitable for controllers using solid-state logic technology:  Single lifts and duplex groups.  Drive speed up to 2 m/s.  Passenger lifts in low traffic situations in medium-rise buildings, i.e. up to 12 stories (e.g. residential buildings and small hotels).  Goods, bullion lifts in low-rise commercial buildings (e.g. offices, hotels, hospitals). PLC controller (computer based technology) The advent of personal computers has made microprocessor technology affordable for many other fields. Elevator Concepts utilizes a special type of industrial computer called a Programmable Logic Controller PLC to control the logic of more complex jobs. They are very dependable, compact, and simple to troubleshoot. Computer based controllers are suitable for the following:  All lifts types.  All drive speeds (i.e. 0.5 m/s to 10 m/s).  Lift groups of all sizes. ELEVATOR SELECTION The selection of elevators requires the simultaneous consideration of several factors: Adequate elevator service for the intended building usage Economics of elevator selection Architectural integration of space assigned to elevators, including lobbies, shafts, and machine rooms ELEVATOR SELECTION The criteria usually used in determining elevator service quality are: Interval or lobby dispatch time Average time between departure of cars from the lobby Average lobby time or average lobby waiting time Average time spent by a passenger between arriving at the lobby and leaving the lobby in the car. The average waiting time in the lobby should be half the interval. (see table) Handling capacity Indicates the maximum number of passengers that can be handled in a given period – usually 5 minutes, thus the term 5-minute handling capacity. When expressed as a percentage of the building’s population, it is called percent handling capacity. ELEVATOR SELECTION Travel time or average trip time Average time spent by passengers from the moment they arrive at the lobby to the moment the leave the car at an upper floor. A trip of less than a minute is highly desirable, a 75-second trip is acceptable, a 90-second trip is annoying, and a 120-second trip is the limit of toleration. Round-trip time Average time required for a car to make a round trip, starting from the lower terminal and returning to it. The time includes a determined number of upper-floor stops in one direction and, when calculating elevator requirements based on up-peak traffic, an express trip. Registration time Waiting time at an upper floor after registering a call PHYSICAL PROPERTIES AND SPATIAL REQUIREMENTS OF ELEVATORS  SHAFTS AND LOBBIES Lobbies obviously must be located above each other. The ground-floor elevator lobby (also called the lower terminal) must be conveniently located with respect to the main entrances. The equipment within or adjacent to this area should include public telephones, a building directory, elevator indicators, and possibly a control desk. All lobbies should be adequate in area for the peak-load gathering of passengers to ensure rapid and comfortable service to all. The number of people contributing to the period of peak-load (15- to 20-minute peak) determines the required lobby area on the floor. Not less than 0.5sm floor space/person should be provided at peak periods for waiting passengers at a given elevator or bank of elevators. The hallways leading to such lobbies should also provide at least 0.5sm floor space/person, approaching the lobby. Under relaxed conditions, density is about 0.65sm/person. Multiple cars in a group with common shafts shall be separated by steel 'I' beams, which can allow the easy passage of air between individuals shafts. This would avoid the 'piston effect', and its consequent negative impact upon ride quality and noise in the lobbies. LOCATION OF ELEVATORS Elevators should be located so that the building entrances with the heaviest traffic shall have adequate elevator service. Elevators should be as near to the center of the building area served as practicable, taking into consideration the distance from the elevator bank or banks to the most distant functional areas do not exceed a maximum of 45 meters. As a general guide, the lobby width between two banks of passenger elevators shall not be less than 3600 mm and the lobby width between two banks of service elevators should not be less than 4200 mm. When designing the service core in relation to the floor plate, the designer must ensure that the elevator lobby should not be used as a common or public thoroughfare at ground-floor level. Where elevators are accessed from corridors, they shall be located on one side of the corridor only and shall be set back from the line of circulating corridors. Elevator ingress/egress shall be from a distinct elevator lobby and not directly from a corridor. Elevator lobbies generate noise and shall be acoustically isolated from areas sensitive to noise and vibration. Elevators shall not be placed over occupied spaces as this shall require counter-weight safeties and reinforced pits. LOCATION OF ELEVATORS  Egress stairs shall preferably be located adjacent to elevator lobbies when possible.  Any decentralized banks and/or clustering of elevators shall be planned to include at least two cars to maintain an acceptable dispatch interval between cars and to ensure continuity of service.  Elevators shall preferably provide positive separation between passenger and freight /service traffic flows.  In facilities that utilize interstitial floors and mechanical penthouses, at least one elevator shall stop on these floors to facilitate equipment maintenance and removal. FIREMAN’S LIFT Firefighting or FIREMAN’S LIFT is an essential provision in all of the high-rise buildings. The important requirements for design and installation of such a lift are:  Break-glass key switch (at G/F to control the lift)  Minimum duty load, say 630 kg (for firefighting equipment)  Minimum internal dimensions, 1100mm(W)x1400mm(D) x 2000mm(H)  An emergency hatch in the car roof  Manufactured from non-combustible material  A two-way intercom  1 hour fire-resisting doors of 800mm(W)x2000mm(H)  A maximum of 60 sec to run full building height  Dual power supplies (normal + emergency) LAYOUT OF ELEVATOR GROUPS A group of 3 or more is needed to ensure that the waiting interval between them is not too great. The cars must all be close enough that an intending user can take whichever one arrives first. A moderately fast walking speed is 0.9m/s. If the landing doors are to remain open for 4 seconds, then an unobstructed person can walk briskly a distance of 3.60m before the doors begin to close again. 2 or 3 cars can be conveniently located side by side. 4 in a row or 2 opposite 2 are both acceptable for a group of 4. 5 in a row is too long a distance for a walk. Door-open time has to be increased to compensate for the walking distance, thus reducing the performance of the car group. 5, 6, 7, or 8 cars are best located opposite each other. Grouping more than 8 cars should be avoided. With larger number of cars, one is not filled before the next one arrives, and this causes confusion on the part of the arriving passengers. This, in turn, increases the number of people waiting at the lobby. DO’s and DONT’s in ELEVATOR DESIGN PLANNING LOCATE ELEVATORS IN THE HOISTWAY IN THE SERVICE CORE AND SET PASSENGER ELEVATORS BACK 600mm (2 ft) FROM CORRIDOR LINE LOCATE SERVICE ELEVATORS IN THE HOISTWAY IN THE SERVICE CORE AND SET SERVICE ELEVATORS BACK 1800mm (6 ft) FROM CORRIDOR LINE PROVIDE POSITIVE SEPARATION OF PASSENGER & SERVICE TRAFFIC PROVIDE 4.2 m (14 ft) MIN WIDTH SERVICE ELEVATOR LOBBIES PROVIDE 3.6 m (12 ft) MIN WIDTH PASSENGER ELEVATOR LOBBIES PROVIDE STAIRS ADJACENT TO PASSENGER & SERVICE ELEVATOR LOBBIES DETERMINING A WORKABLE ELEVATOR SYSTEM  PASSENGER/TRIP 10 12 14 16 18 20 22 18 8 9 10 11 12 13 13 NUMBER OF FLOORS SERVED 16 8 9 10 10 11 12 12 14 7 8 9 9 10 11 11 12 7 8 9 9 10 10 10 10 6 7 8 8 9 9 9 8 6 6 7 7 8 8 8 6 5 5 6 6 7 7 7 PROBABLE STOPS LOBBY LOADING TIME CAPACITY 80% LOAD TIME TO LOAD (secs) 2000 10 8 2500 12 11 3000 16 14 3500 19 16 4000 22 17 DOOR CLOSING TIME TIME TO WIDTH TYPE CLOSE (secs) 3'-0" Single slide 4.3 3'-0" Two-speed 3.8 3'-0" Center opening 2.9 3'-6" Single slide 4.9 3'-6" Two-speed 4.4 3'-6" Center opening 3.3 4'-0" Two-speed 5.0 4'-0" Center opening 3.7 DOOR OPENING TIME TIME REQUIRED PRIOR TO TRANSFER w/o w/ PREMATURE TYPE WIDTH PREMATURE OPENING OPENING Single slide 3'-0" 2.5 1.0 3'-6" 2.9 1.4 Two-speed 3'-0" 2.9 0.8 3'-6" 3.1 0.9 4'-0" 3.7 1.0 Center opening 3'-0" 2.3 0.5 3'-6" 2.5 0.6 4'-0" 2.7 0.8 TRANSFER TIME CAPACITY TIME TO EXIT 2000 1.2 2500 1.5 3000 1.6 3500 1.8 4000 2 TIME ELEMENTS Number of probable stops Time to load passengers Time to close door and start car Time to open the doors when car returns to lobby Time to start car and stop car when it returns to lobby TOTAL TIME SPENT AT THE LOBBY Time to open the doors at a floor stop Time to transfer passengers at a floor stop Time to close door at each stop Time to start and stop at each floor stop TOTAL TIME SPENT AT EACH FLOOR STOP TIME TO RUN FROM GROUND FLOOR TO TOP AND BACK TO GROUND