UNDERSTANDING BUILDING AUTOMATION AND CONTROL SYSTEMS

Building Automation Systems (BAS) are centralized, interlinked, networks of hardware and software, which monitor and control the environment in commercial, industrial, and institutional facilities. While managing various building systems, the automation system ensures the operational performance of the facility as well as the comfort and safety of building occupants.

Typically, such control systems are installed in new buildings or as part of a renovation where they replace an outdated control system.

RELATED TERMSYou may hear any of the following terms to describe the control or automation of buildings:

Building Automation and Control Systems (BACS), Building Control System (BCS), and/or Building Management System (BMS)—same as "Building Automation System" or the subject of this page.

Controls—This term is appropriate in describing discrete devices that control particular pieces of equipment or processes.

Direct Digital Control (DDC)—describes the communication method used in modern devices (hardware and software). Collectively, DDC products control various building systems and form the automation system.

Energy Management System (EMS)—generally understood to be the same as a "Building Automation System" but may have special emphasis on energy metering/monitoring

Energy Management and Control System—well, you're getting the idea.

Smart (Intelligent) Building—a building equipped with a data-rich BAS.

WHAT IS CONTROLLED?Generally, building automation begins with control of mechanical, electrical, and plumbing (MEP) systems. For instance, the heating, ventilation, and air-conditioning (HVAC) system is almost always controlled, including control of its various pieces of equipment such as:

Chillers

Boilers

Air Handling Units (AHUs)

Roof-top Units (RTUs)

Fan Coil Units (FCUs)

Heat Pump Units (HPUs)

Variable Air Volume boxes (VAVs)

Lighting control is, likewise, low-hanging fruit for optimizing building performance.

Other systems that are often controlled and/or brought under a complete automation system include:

Power monitoring

Security

Close circuit video (CCTV)

Card and keypad access

Fire alarm system

Elevators/escalators

Plumbing and water monitoring

TYPES OF BUILDING AUTOMATION AND CONTROL SYSTEMSEarly control systems were pneumatic or air-based and were generally restricted to controlling various aspects of the HVAC system. Common pneumatic devices include controllers, sensors, actuators, valves, positioners, and regulators. Due to their large base of installation throughout the 1960s and 1970s, pneumatic control systems are still in place in a majority of existing buildings, especially in established metropolitan areas.

Analog electronic control devices became popular throughout the 1980s. They provided faster response and higher precision than pneumatics.

However, it was not until digital control or DDC devices came on the scene in the 1990s that a true automation system was possible. However, as there were no established standards for this digital communication, various manufacturers, created their own (proprietary) communication methods.

The automation system was fully functional but was not "interoperable" or capable of mixing products from various manufacturers. Thus, a given building or portfolio could be "locked" into a specific manufacturer. This is not necessarily a problem unless the relationship with the associated service provider is challenging.

By the late 1990s and especially into the 2000s, movements were afoot to standardize on "open" communication systems. The American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) developed the BACnet communication protocol that eventually became the industry open standard.

WHAT DOES A BAS LOOK LIKE?Most of the automation system is behind the scenes as hardware devices mounted to equipment or hidden underfloor or in the ceiling. Some personalized control can be made available through thermostat-like devices. From a central management perspective, the BAS resides as software on an operator workstation (computer) or is available as a web page.

Various types of "controllers" manage equipment and portions of the network. "Sensors" provide input data to the controllers.

Here is a generalized view of a BAS:

WHO INSTALLS OR SERVICES A BAS?A properly trained in-house staff can manage the operation and, sometimes, the maintenance of the BAS. However, system design and initial installation is almost always accomplished by controls professionals such as dedicated controls contractors or system integrators. In practice, the controls contractor is a sub-contractor to the mechanical contractor. Sometimes, the mechanical contractor will have a dedicated controls division. Electrical contractors with controls teams are also common and multi-functional system integrators are becoming more common for today's complex facilities.

These controls professionals can provide on-going service or train your in-house staff to self-perform service.

The automation system can also offer you an incredible amount of data related to building performance, and with this data in hand, you can make more intelligent decisions.

And, if you are building green, be aware that an automation system can contribute greatly to your ability to earn such recognition as the EPA ENERGY STAR or the LEED certification associated with the U.S. Green Building Council (USGBC).

TODAY'S BAS TRENDSWhen the subject is intelligent buildings, you know that things don't stand still. Here are a few trends influencing building automation:

Wireless technology is beginning to replace traditionally wired BAS infrastructure. Thus far, however, the wireless technology is limited to sensor-type devices and suffers from issues including a lack of clear wireless standard, short battery life, and communication challenges through various types of building structures and materials.

Enterprise-level initiatives are making the communication protocol of the BAS less important.

While it is quite common to replace a pneumatic control system with a direct digital control (DDC) system, pneumatic-to-DDC bridging strategies also exist.

More controls are coming to the construction site, factory pre-mounted to equipment.

Hardware and software continues to be augmented by energy-related visuals.

There has been tremendous consolidation among BAS manufacturers, leaving relatively few independent players (such as KMC Controls).

Building automation.

Building automation is the automatic centralized control of a building's heating, ventilation and air conditioning, lighting and other systems through a Building Management System or Building Automation System (BAS). The objectives of building automation are improved occupant comfort, efficient operation of building systems, and reduction inenergy consumption and operating costs.

Building automation is an example of a distributed control system - the computer networking of electronic devices designed to monitor and control the mechanical, security, fire and flood safety, lighting (especially emergency lighting), HVAC and humidity control and ventilation systems in a building.[1]

BAS core functionality keeps building climate within a specified range, provides light to rooms based on an occupancy schedule (in the absence of overt switches to the contrary), monitors performance and device failures in all systems, and provides malfunction alarms to building maintenance staff. A BAS should reduce building energy and maintenance costs compared to a non-controlled building. Most commercial, institutional, and industrial buildings built after 2000 include a BAS. Many older buildings have been retrofitted with a new BAS, typically financed through energy and insurance savings, and other savings associated with pre-emptive maintenance and fault detection.

A building controlled by a BAS is often referred to as an intelligent building, "smart building", or (if a residence) a "smart home". Commercial and industrial buildings have historically relied on robust proven protocols (like BACnet) while proprietary and poorly integrated purpose-specific protocols (like X-10 or those from Honeywell, Siemens or other major manufacturers of smart thermostats, etc.) were used in homes. Recent IEEE standards (notably IEEE 802.15.4, IEEE 1901 and IEEE 1905.1, IEEE 802.21, IEEE 802.11ac, IEEE 802.3at) and consortia efforts like nVoy (which verifies IEEE 1905.1 compliance) or QIVICON have provided a standards-based foundation for heterogeneous networking of many devices on many physical networks for diverse purposes, and quality of service and failover guarantees appropriate to support human health and safety.

Almost all multi-story green buildings are designed to accommodate a BAS for the energy, air and water conservation characteristics. Electrical device demand response is a typical function of a BAS, as is the more sophisticated ventilation and humidity monitoring required of "tight" insulated buildings. Most green buildings also use as many low-power DC devices as possible, typically integrated with power over Ethernet wiring, so by definition always accessible to a BAS through the Ethernet connectivity.

Automation systemThe term "Building Automation System", loosely used, refers to any electrical control system that is used to controls a buildings heating, ventilation and air conditioning (HVAC) system. Modern BAS can also control indoor and outdoor lighting as well as security, fire alarms, and basically everything else that is electrical in the building. Old HVAC control systems, such as 24VDC wired thermostats or pneumatic controls, are a form of automation but lack the modern systems flexibility and integration.

Types of inputs and outputsAnalog inputs are used to read a variable measurement. Examples are temperature, humidity and pressure sensors which could be thermistor, 4-20 mA, 0-10 volt or platinum resistance (resistance temperature detector), or wireless sensors.

A digital input indicates if a device is turned on or not. Some examples of an inherently digital input would be a 24VDC/AC signal, current switch, an air flow switch, or a volta-free relay contact (Dry Contact). Digital inputs could also be pulse type inputs counting the frequency of pulses over a given period of time. An example is a turbine flow meter transmitting rotation data as a frequency of pulses to an input.

Analog outputs control the speed or position of a device, such as a variable frequency drive, an I-P (current to pneumatics) transducer, or a valve or damper actuator. An example is a hot water valve opening up 25% to maintain a set point. Another example is a variable frequency drive ramping up a motor slowly to avoid a hard start.

Digital outputs are used to open and close relays and switches as well as drive a load upon command. An example would be to turn on the parking lot lights when a photocell indicates it is dark outside. Another example would be to open a valve by allowing 24VDC/AC to pass through

the output powering the valve. Digital outputs could also be pulse type outputs emitting a frequency of pulses over a given period of time. An example is an energy meter calculating kWh and emitting a frequency of pulses accordingly.

InfrastructureController

Various components that make up a building automation system

Controllers are essentially small, purpose-built computers with input and output capabilities. These controllers come in a range of sizes and capabilities to control devices commonly found in buildings, and to control sub-networks of controllers.

Inputs allow a controller to read temperatures, humidity, pressure, current flow, air flow, and other essential factors. The outputs allow the controller to send command and control signals to slave devices, and to other parts of the system. Inputs and outputs can be either digital or analog. Digital outputs are also sometimes called discrete depending on manufacturer.

Controllers used for building automation can be grouped in 3 categories. Programmable Logic Controllers (PLCs), System/Network controllers, and Terminal Unit controllers. However an additional device can also exist in order to integrate 3rd party systems (i.e. a stand-alone AC system) into a central Building automation system).

PLC's provide the most responsiveness and processing power, but at a unit cost typically 2 to 3 times that of a System/Network controller intended for BAS applications. Terminal Unit controllers are usually the least expensive and least powerful.

PLC's may be used to automate high-end applications such as clean rooms or hospitals where the cost of the controllers is less of a concern.

In office buildings, supermarkets, malls, and other common automated buildings the systems will use System/Network controllers rather than PLC's. Most System controllers provide general purpose feedback loops, as well as digital circuits, but lack the millisecond response time that PLC's provide.

System/Network controllers may be applied to control one or more mechanical systems such as an Air Handler Unit (AHU), boiler, chiller, etc., or they may supervise a sub-network of controllers. In the diagram above, System/Network controllers are often used in place of PLCs.

Terminal Unit controllers usually are suited for control of lighting and/or simpler devices such as a package rooftop unit, heat pump, VAV box, or fan coil, etc. The installer typically selects 1 of the available pre-programmed personalities best suited to the device to be controlled, and does not have to create new control logic.

OccupancyOccupancy is one of two or more operating modes for a building automation system. Unoccupied, Morning Warmup, and Night-time Setback are other common modes.

Occupancy is usually based on time of day schedules. In Occupancy mode, the BAS aims to provides a comfortable climate and adequate lighting, often with zone-based control so that users on one side of a building have a different thermostat (or a different system, or sub system) than users on the opposite side.

A temperature sensor in the zone provides feedback to the controller, so it can deliver heating or cooling as needed.

If enabled, Morning Warmup (MWU) mode occurs prior to Occupancy. During Morning Warmup the BAS tries to bring the building to set point just in time for Occupancy. The BAS often factors in outdoor conditions and historical experience to optimize MWU. This is also referred to as Optimised Start.

An override is a manually initiated command to the BAS. For example, many wall-mounted temperature sensors will have a push-button that forces the system into Occupancy mode for a set number of minutes. Where present, web interfaces allow users to remotely initiate an override on the BAS.

Some buildings rely on occupancy sensors to activate lighting and/or climate conditioning. Given the potential for long lead times before a space becomes sufficiently cool or warm, climate conditioning is not often initiated directly by an occupancy sensor.

LightingLighting can be turned on, off, or dimmed with a building automation or lighting control system based on time of day, or on occupancy sensor, photosensors and timers. [2] One typical example is to turn the lights in a space on for a half hour since the last motion was sensed. A photocell placed outside a building can sense darkness, and the time of day, and modulate lights in outer offices and the parking lot.

Lighting is also a good candidate for Demand response, with many control systems providing the ability to dim (or turn off) lights to take advantage of DR incentives and savings.

In newer buildings, the lighting control is based on the field bus DALI. Lamps with DALI ballasts are fully dimmable. DALI can also detect lamp and ballast failures on DALI luminaires and signals failures.

Air handlersMost air handlers mix return and outside air so less temperature/humidity conditioning is needed. This can save money by using less chilled or heated water (not all AHUs use chilled/hot water circuits). Some external air is needed to keep the building's air healthy. To optimize energy efficiency while maintaining healthy indoor air quality (IAQ),demand control (or controlled) ventilation (DCV) adjusts the amount of outside air based on measured levels of occupancy.

Analog or digital temperature sensors may be placed in the space or room, the return and supply air ducts, and sometimes the external air. Actuators are placed on the hot and chilled water valves, the outside air and return air dampers. The supply fan (and return if applicable) is started and stopped based on either time of day, temperatures, building pressures or a combination.

Constant volume air-handling unitsThe less efficient type of air-handler is a "constant volume air handling unit," or CAV. The fans in CAVs do not have variable-speed controls. Instead, CAVs open and close dampers and water-supply valves to maintain temperatures in the building's spaces. They heat or cool the spaces by opening or closing chilled or hot water valves that feed their internal heat exchangers. Generally one CAV serves several spaces

Variable volume air-handling unitsA more efficient unit is a "variable air volume (VAV) air-handling unit," or VAV.[3] VAVs supply pressurized air to VAV boxes, usually one box per room or area. A VAV air handler can change the pressure to the VAV boxes by changing the speed of a fan or blower with a variable frequency drive or (less efficiently) by moving inlet guide vanes to a fixed-speed fan. The amount of air is determined by the needs of the spaces served by the VAV boxes.

Each VAV box supply air to a small space, like an office. Each box has a damper that is opened or closed based on how much heating or cooling is required in its space. The more boxes are open, the more air is required, and a greater amount of air is supplied by the VAV air-handling unit.

Some VAV boxes also have hot water valves and an internal heat exchanger. The valves for hot and cold water are opened or closed based on the heat demand for the spaces it is supplying. These heated VAV boxes are sometimes used on the perimeter only and the interior zones are cooling only.

A minimum and maximum CFM must be set on VAV boxes to assure adequate ventilation and proper air balance.

VAV hybrid systemsAnother variation is a hybrid between VAV and CAV systems. In this system, the interior zones operate as in a VAV system. The outer zones differ in that the heating is supplied by a heating fan in a central location usually with a heating coil fed by the building boiler. The heated air is ducted to the exterior dual duct mixing boxes and dampers controlled by the zone thermostat calling for either cooled or heated air as needed.

Central plantA central plant is needed to supply the air-handling units with water. It may supply a chilled water system, hot water system and a condenser water system, as well as transformers and auxiliary power unit for emergency power. If well managed, these can often help each other. For example, some plants generate electric power at periods with peak demand, using a gas turbine, and then use the turbine's hot exhaust to heat water or power an absorptive chiller.

Chilled water systemChilled water is often used to cool a building's air and equipment. The chilled water system will have chiller(s) and pumps. Analog temperature sensors measure the chilled water supply and return lines. The chiller(s) are sequenced on and off to chill the chilled water supply.

A chiller is a refrigeration unit designed to produce cool (chilled) water for space cooling purposes. The chilled water is then circulated to one or more cooling coils located in air handling units, fan-coils, or induction units. Chilled water distribution is not constrained by the 100 foot separation limit that applies to DX systems, thus chilled water-based cooling systems are typically used in larger buildings. Capacity control in a chilled water system is usually achieved through modulation of water flow through the coils; thus, multiple coils may be served from a single chiller without compromising control of any individual unit. Chillers may operate on either the vapor compression principle or the absorption principle. Vapor compression chillers may utilize reciprocating, centrifugal, screw, or rotary compressor configurations. Reciprocating chillers are commonly used for capacities below 200 tons; centrifugal chillers are normally used to provide higher capacities; rotary and screw chillers are less commonly used, but are not rare. Heat rejection from a chiller may be by way of an air-cooled condenser or a cooling tower (both discussed below). Vapor compression chillers may be bundled with an air-cooled condenser to provide a packaged chiller, which would be installed outside of the building envelope. Vapor compression chillers may also be designed to be installed separate from the condensing unit; normally such a chiller would be installed in an enclosed central plant space. Absorption chillers are designed to be installed separate from the condensing unit.

Condenser water systemCooling tower(s) and pumps are used to supply cool condenser water to the chillers. Because the condenser water supply to the chillers has to be constant, variable speed drives are commonly used on the cooling tower fans to control temperature. Proper cooling tower temperature assures the proper refrigerant head pressure in the chiller. The cooling tower set point used depends upon the refrigerant being used. Analog temperature sensors measure the condenser water supply and return lines.Hot water system

The hot water system supplies heat to the building's air-handling unit or VAV box heating coils, along with the domestic hot water heating coils.The hot water system will have a boiler(s) and pumps. Analog temperature sensors are placed in the hot water supply and return lines. Some type of mixing valve is usually used to control the heating water loop temperature. The boiler(s) and pumps are sequenced on and off to maintain supply.

The installation and integration of variable frequency drives can lower the energy consumption of the building's circulation pumps to about 15% of what they had been using before. If that sounds hard to believe, I'll explain, and we can do the math. A variable frequency drive functions by modulating the frequency of the electricity provided to the motor that it powers. In the USA, the electrical grid uses a frequency of 60 Hertz or 60 cycles per second. Variable frequency drives are able to decrease the output and energy consumption of motors by lowering the frequency of the electricity provided to the motor, however the relationship between motor output and energy consumption is not a linear one. If the variable frequency drive provides electricity to the motor at 30 Hertz, the output of the motor will be 50% because 30 Hertz divided by 60 Hertz is 0.5 or 50%. The energy consumption of a motor running at 50% or 30 Hertz will not be 50%, but will instead be something like 18% because the relationship between motor

output and energy consumption are not linear. The exact ratios of motor output or Hertz provided to the motor (which are effectively the same thing), and the actual energy consumption of the variable frequency drive / motor combination depend on the efficiency of the variable frequency drive. For example, because the variable frequency drive needs power itself to communicate with the building automation system, run its cooling fan, etc., if the motor always ran at 100% with the variable frequency drive installed the cost of operation or electricity consumption would actually go up with the new variable frequency drive installed. The amount of energy that variable frequency drives consume is nominal and is hardly worth consideration when calculating savings, however it did need to be noted that VFD's do consume energy themselves. Due to the fact that the variable frequency drives rarely ever run at 100% and spend most of their time in the 40% output range, and the fact that now the pumps completely shut down when not needed, the variable frequency drives have reduced the energy consumption of the pumps to around 15% of what they had been using before.

Alarms and securityAll modern building automation systems have alarm capabilities. It does little good to detect a potentially hazardous or costly situation if no one who can solve the problem is notified. Notification can be through a computer (email or text message), pager, cellular phone voice call, audible alarm, or all of these. For insurance and liability purposes all systems keep logs of who was notified, when and how.

Alarms may immediately notify someone or only notify when alarms build to some threshold of seriousness or urgency. At sites with several buildings, momentary power failures can cause hundreds or thousands of alarms from equipment that has shut down — these should be suppressed and recognized as symptoms of a larger failure. Some sites are programmed so that critical alarms are automatically re-sent at varying intervals. For example, a repeating critical alarm (of an Uninterruptible power supply in 'bypass') might resound at 10 minutes, 30 minutes, and every 2 to 4 hours thereafter until the alarms are resolved.

Common temperature alarms are: space, supply air, chilled water supply, hot water supply. Pressure, humidity, biological and chemical sensors can determine if ventilation systems

have failed mechanically or become infected with contaminants that affect human health. Differential pressure switches can be placed on a filter to determine if it is dirty or otherwise

not performing. Status alarms are common. If a mechanical device like a pump is requested to start, and the

status input indicates it is off, this can indicate a mechanical failure. Or, worse, an electrical fault that could represent a fire or shock hazard.

Some valve actuators have end switches to indicate if the valve has opened or not. Carbon monoxide and carbon dioxide sensors can tell if concentration of these in the air are

too high, either due to fire or ventilation problems in garages or near roads. Refrigerant sensors can be used to indicate a possible refrigerant leak. Current sensors can be used to detect low current conditions caused by slipping fan belts,

clogging strainers at pumps, or other problems.

Security systems can be interlocked to a building automation system. If occupancy sensors are present, they can also be used as burglar alarms. Because security systems are often deliberately sabotaged, at least some detectors or cameras should have battery backup and wireless connectivity and the ability to trigger alarms when disconnected. Modern systems typically use power-over-Ethernet (which can operate a pan-tilt-zoom camera and other devices up to 30-90 watts) which is capable of charging such batteries and keeps wireless networks free for genuinely wireless applications, such as backup communication in outage.

Fire alarm panels and their related smoke alarm systems are usually hard-wired to override building automation. For example: if the smoke alarm is activated, all the outside air dampers close to prevent air coming into the building, and an exhaust system can isolate the blaze. Similarly, electrical fault detection systems can turn entire circuits off, regardless of the number of alarms this triggers or persons this distresses. Fossil fuel combustion devices also tend to have their own over-rides, such as natural gas feed lines that turn off when slow pressure drops are detected (indicating a leak), or when excess methane is detected in the building's air supply.

Good BAS are aware of these overrides and recognize complex failure conditions. They do not send excessive alerts, nor do they waste precious backup power on trying to turn back on devices that these safety over-rides have turned off. A poor BAS, almost by definition, sends out one alarm for every alert, and does not recognize any manual, fire or electric or fuel safety override. Accordingly good BAS are often built on safety and fire systems.

Room automationRoom automation is a subset of building automation and with a similar purpose, it is the consolidation of one or more systems under centralized control, though in this case in one room.

The most common example of room automation is corporate boardroom, presentation suites, and lecture halls, where the operation of the large number of devices that define the room function (such as videoconferencing equipment, video projectors, lighting control systems, public address systems etc.) would make manual operation of the room very complex. It is common for room automation systems to employ a touch screen as the primary way of controlling each operation.

Elevators Types and Classification

Introduction  

An elevator   (or lift in the Commonwealth excluding Canada) 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. 

There are three types of convoying methods in buildings, Elevators & Escalators & Ramps, and they have different dimensions and uses according to building type & number of users in it. 

Elevator Types1. According to hoist mechanism.2. According to building height.3. According to building type.4. According to elevator Location.5. According to Special uses.

1- According to hoist mechanism:

Elevators will be classified according to hoist mechanism to 4 main types as follows:

1. Hydraulic Elevators 2. Traction Elevators 3. Climbing elevator 4. Pneumatic Elevators 

1- Hydraulic Elevators (Push Elevators)

Hydraulic Elevators

Hydraulic elevators are supported by a piston at the bottom of the elevator that pushes the elevator up. They are used for low-rise applications of 2-8 stories and travel at a maximum speed of 200 feet per minute. The machine room for hydraulic elevators is located at the lowest level adjacent to the elevator shaft. Hydraulic elevators have many two main types as follows: 

A- Holed (Conventional) Hydraulic Elevators 

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. Max travel distance is approximately 60 feet. 

B- Hole-less Hydraulic Elevators 

They have a piston on either side of the cab. It can be divided to 3 different types as follows: 

a- Telescopic Hydraulic Elevators:

Telescopic Hydraulic Elevators

In this configuration, 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. 

b- Non-telescoping (single stage) Hydraulic Elevators: 

Non-telescoping (single stage) Hydraulic Elevators

it has one piston and only allows about 20 feet of travel distance. 

c- Roped Hydraulic Elevators 

Roped Hydraulic Elevators 

They use a combination of ropes and a piston to move the elevator. Maximum travel distance is about 60 feet. 

2- Traction Elevators (Pull Elevators)  

Traction Elevators (Pull Elevators)

Traction elevators are lifted by ropes, which pass over a wheel attached to an electric motor above the elevator shaft. They are used for mid and high-rise applications and have much higher travel speeds than hydraulic elevators. A counter weight makes the elevators more efficient. Traction elevators have 3 main types as follows: 

A- Geared Traction Elevators: 

Geared Traction Elevators

they have a gearbox that is attached to the motor, which drives the wheel that moves the ropes. Geared traction elevators are capable of travel speeds up to 500 feet per minute. 

B- Gear-less Traction Elevators:

Gear-less Traction Elevators

they have the wheel attached directly to the motor. Gear-less traction elevators are capable of speeds up to 2000 feet per minute. 

C- Machine-Room-Less Elevators:

Machine-Room-Less Elevators

they are typically traction elevators that do not have a dedicated machine room above the elevator shaft. 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. 

3- Climbing elevator

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.

4- Pneumatic Elevators  

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. 

2- 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 

3- According to building type

Elevators will be classified according to building type to 6 main types as follows: 

1. Hospital Elevators.2. Residential /Domestic Elevators.3. Agricultural Elevators.4. Industrial Elevators.5. Commercial Elevators.6. Parking buildings Elevators.

1- Hospital Elevators  

Hospital Elevators

A- Hospital Bed Elevators Hospital bed elevators generally transport patients who are not well enough to sit up even in a wheelchair. One of the features of bed elevators should be its ability to transport the patient has smoothly as possible with minimal amount of bumping and jostling. Many contemporary bed elevators are manufactured to consume extremely low amounts of power and to be durable with a number of safety features built-in. Hospital bed elevators generally draw very little power so that should there be a power outage they are still operational off the hospital's backup power supply. Most often there will be a rear and a front entry to the elevator cabin. 

B- Hospital Stretcher Lift They usually are smaller than bed elevators. This particular type of elevator is usually hydraulic or traction based depending on the location of the machine room. They are specifically manufactured to be low-noise bed elevators that smoothly transport patients, doctors, nurses and hospital staff between floors, allowing them the utmost in comfort. Because hospital bed elevators are only used for transporting patients and hospital staff they arrived at their location quite quickly, eliminating lengthy waits. Many of these bed elevators are key operated so as to prohibit use by the general public. 

2- Residential /Domestic Elevators   They are usually just on a much smaller scale than industrial or commercial elevators. 

A- Passenger Elevators 

Passenger Elevators

Domestic elevators which are intended to move passengers up and down stairs in a multilevel residence are quite similar to those used in large public buildings. They can be built either inside the home or outside the home and can be pneumatic vacuum, electric, hydraulic or cable elevators. Most often domestic elevators designed for carrying passengers in a residential setting only carry perhaps two to four people safely and comfortably. 

B- Stairway Elevators 

Stairway Elevators

Stairway elevators are generally installed in homes where someone in the family has problems with mobility. This type of domestic elevators simply runs on a rail up and down and existing staircase. They can run either in a straight line or around a curved stairway. Stairway elevators can be constructed both inside and outside the home.

b.1 - Vertical Wheelchair Elevators 

Vertical Wheelchair Elevators 

Interior vertical wheelchair elevators can easily be installed when space is limited. They can be constructed in such a way as to allow both front and rear entry and the platform is generally 4.5 feet by 5 feet, unless a custom size is called for. Vertical elevators are called for when the staircase winds around several levels. 

b.2 - Wheelchair Elevators on an Incline 

Wheelchair Elevators on an Incline

Wheelchair elevators on an incline are generally installed when the staircase simply goes up one level or perhaps two. If there are several winds in the staircase, wheelchair elevators on an incline would not be well suited. Most often this type of elevator is called for when there is not adequate space to facilitate a more spacious vertical wheelchair elevator. 

C- Dumbwaiters Elevators 

Dumbwaiters Elevators

They are small freight elevators intended to carry objects rather than people , Whenever groceries or laundry need to be sent up and down the stairs without making unnecessary trips that can quickly tire people , people can simply place what needs to be transported in the dumbwaiter and press the button to send it up or down stairs. Dumbwaiters are most often built into or adjacent to a wall.  

A simple dumbwaiter is a movable frame in a shaft, dropped by a rope on a pulley, guided by rails; most dumbwaiters have a shaft, car, and capacity smaller than those of passenger elevators, usually 100 to 1000 lbs 

3- Agricultural applications:

A- Bucket Elevators Bucket elevator used to move crops which have been newly harvested up and into silo. Bucket elevators are manufactured in such a way that they can move heavy loads quite easily. They can be belt driven or chain driven and they can move vertically, horizontally or at an incline.  

A.1- Centrifugal discharge elevators 

Centrifugal discharge elevators

Bucket elevators are sometimes referred to as conveyor buckets, most often when the movement is horizontal or on an incline. However, technically speaking, vertical movement is also accomplished with a conveyor belt or chain. The centrifugal discharge bucket elevator is perhaps the most common type. Of course, as the name implies the elevator is driven by centrifugal force. This type of elevator has lower speeds and the buckets are often placed relatively closely together. 

A.2 Vertical bucket Elevators 

Vertical bucket Elevators

Vertical bucket elevators usually have buckets that are well spaced with bottoms that are rounded, and are often referred to as grain legs. Part of the reason for this is balance which keeps the contents in the buckets as they move up the elevator so that spillage isn't a problem. Vertical bucket elevators need to be used at a much slower pace both to avoid spilling contents and also because much of the time they carry loads that are quite heavy. 

4- Industrial Elevators  

The most common types of industrial elevators are hoist elevators and incline elevators. These types of elevators are built to carry huge amounts of weight effortlessly, therefore the term industrial elevators. This type of elevators is used in construction, warehouses, and shipyards. 

A-Hoist Elevators 

Hoist Elevators

Hoist elevators are operated by a pulley or series of pulleys and they can be a simple platform or a cage in which humans or heavy materials are moved up and down during industrial applications. Generally, a pulley operates a rope or chain that wraps around a drum causing the elevator to rise or descend. It is said that hoist elevators are powered by either electricity or air, but even that isn't quite true because electricity is needed to pump air. Hoist elevators carrying materials and equipment to upper levels as needed while the building is being constructed. They are also commonly used to load equipment and supplies on large seagoing vessels. 

B- Incline Elevators 

Incline Elevators

The equipment and supplies are placed on a form of conveyor belt that continues turning bringing the cargo up to its destination where it is quickly unloaded as the belt continues turning around. This is a much quicker method of loading and unloading cargo than with a hoist elevator because there is no stopping to unload. Everything happens in one fluid motion. Incline elevators when used for industrial purposes are usually temporary and mobile. Many are on wheels and can be easily moved from one dock or location to the next. 

5- Parking Elevators

A- Parking Elevators for Passengers  

Parking Elevators for Passengers

Most parking garages have parking elevators for passengers that allow them the convenience of going up or down several levels without the necessity of climbing stairs. Sometimes these elevators have front and rear entry and can be built with a number of optional features such as key access to certain floors. Most underground garages have parking elevators for passengers. 

B- Conventional Parking Elevators  

Conventional Parking Elevators

The conventional parking elevators are built to move vehicles to upper or lower levels of the building because of their space saving feature. With ramps on and off parking levels consume a lot of space which could be better utilized as parking spaces for vehicles. With the addition of parking elevators, vehicles can be transported up and down as many levels as necessary by taking up only the space required for that vehicle. But maintain the need for attendants to sit in the car, in the elevator and park it on the floor on which there is space. 

C- Auto Car Parking Elevators  

Auto Car Parking Elevators

As against cars being driven (on ramps) or carried (in car lifts) to different levels in conventional multi-level parking, cars are driven at only one level for parking or retrieval, Cars are parked in steel pallets and a target pallet comes up or down to the driveway level at the press of a button, for parking or retrieval. 

Such car parking systems or auto parking systems are also referred to by various other names in different parts of the world, such as “auto-parking”, "stack-parking", "mechanized parking", "mechanical parking", "parkomat", “modular parking” etc. 

This type can be divided to many different types as follows: 

Auto Car Parking Elevators Types

C.1 Square Type The system arranges many carriers on several intended floors and a lift installed either at both ends or at the center goes up and down with vehicles loaded. It is designed so that vehicles can be parked and retrieved by moving a pallet horizontally. It is safer than other systems and the cutting -edge mechanical car parking system, and operates very smoothly. It is fit for installation in a narrow and long shaped lot or an underground of a building. 

C.2 Level Type The system is designed so that car parking lots move both horizontally and circulary to park vehicles. Many carriers are arrayed in more than one row in the car parking lot and the system works by moving both horizontally and circulary the carriers at both ends of level. 

C.3 Rotary Type A system that two sprockets as a set are fixed; one onto a upper part of a structure and the other onto a lower part and then a cage hung to a attachment of a special chain circulates with vehicles loaded. This system with simple operation and low installation cost requires a small lot for installing equipments and may be divided to subsystems as follows: 

1. Bottom entering type: A type that cars are parted and retrieved at the bottom of parking equiments.2. Middle entering type: A type that cars are parked and retrieved at the middle of parking equiments.3. Top entering type: This type that cars are parked and retrieved at the top of parking equiments. 

C.4 story Type

A system is featured by using all parking lots on the first floor as the place for car parking/retrieval. Carriers are arranged on two levels, where cars are parked through both vertical and horizontal

movements. With short construction period and easy installation, it is fit household use or a small scale parking lot. 

C.5 Puzzle Type

The carriers are arranged on 3-storey and more than 3-story, a specific carrier moves both vertically and horizontally to and from more than one car entrance on the same level, It is an economical system, has safe structures, and designed to utilize space efficiently to install parking equipments. As there are few laws and regulations on this system and the installation period is short. it is fit for utilizing an idle lot in residential areas. 

C.6 Turn Table

A turntable is equipment which changes directions itself utilize efficiently a limited space. The turntable installed in front of parking equipments provides drivers with convenience and safety. 

C.7 Elevator Type

This System is arranged On multi-levels and designed to automatically Carry and park Cars by a lift and a Carrier installed inside parking lots A pallet for parking is built in independently on each level, that is Carried by a Cage from parking lots to the lift that moves Vertically to an entrance/exit. This System one of the most Up-to-date mechanical Car parking System, is featured With Speedy parking/retrieval, widely installed In a City area, and fit for a large Scale Car parking equipment that can maximize Utilization of a limited parking Space. 

C.8 Lift Traverser Type

This is a full automatically mechanical car parking system that minimizes the time for parking/retrieval by the simultaneous movements, both horizontally and vertically, of a car lift. As the utilization of both parking space and floor space can be maximized and easy forward parking/ retrieval of vehicles is possible from any moving lane, and the convenience of user can be maximized. The noise level is low and the durability of car bay is semi-permanent. The scale of car parking can be proportionally balanced and properly coordinated with the building's shape. 

C.9 Cart Type

This is a multi-leveled car parking system and is designed to park vehicles into each parking lots by conveying vehicles automatically with both a up-and-down lift and a parking cart. The carts independently installed on each parking level can retrieve vehicles from parking lots, and more than one lift move simultaneously for car parking/retrieval. This is one of most up-to-date mechanical parking systems with speedy car parking/retrieval and fits a large scale of car parking that can maximize the utilization of the underground space by installing many rows of the carts in the underground. 

6- Commercial Elevators

A- Commercial passenger elevators  

Commercial passenger elevators

A passenger elevator is designed to move people between a building's floors. Passenger elevators capacity is related to the available floor space. 

B- Freight elevators  

A freight elevator, or goods lift, is an elevator designed to carry goods, rather than passengers. Freight elevators are generally required to display a written notice in the car that the use by passengers is prohibited (though not necessarily illegal), though certain freight elevators allow dual use through the use of an inconspicuous riser. Freight elevators are typically larger and capable of carrying heavier loads than a passenger elevator, generally from 2,300 to 4,500 kg. Freight elevators may have manually operated doors, and often have rugged interior finishes to prevent damage while loading and unloading. Although hydraulic freight elevators exist, electric elevators are more energy efficient for the work of freight lifting. 

Freight elevators include the following classes: 

Freight elevators Classes

Class A: General Freight Loading

Where the load is distributed, the weight of any single piece is not more than 1/4 the capacity of the elevator and the load is handled on and off the car platform manually or by means of hand trucks. 

Class B: Motor Vehicle Loading

The freight elevator is used solely to carry automobile trucks or passenger automobiles up to the rated capacity of the elevator. 

Class C1: Industrial Truck Loading

A four-wheeled vehicle may be used to load and unload the elevator. The combined weight of the vehicle and the load cannot exceed the rated capacity and may be rolled onto the platform as a single unit. 

Class C2: Industrial Truck Loading

During loading and unloading, max load on the platform may be up to 150% of the rated capacity. This enables you to use a forklift to load a car with freight weighing up to the rated capacity. 

Class C3: Other forms of Industrial Truck Loading

During the loading and unloading process, the rated capacity must never be exceeded. 

C- Commercial Dumbwaiter  

Commercial Dumbwaiter

They are economic solution for moving material from floor to floor in a multi-level commercial environment. They can carry loads up to 750 lbs. Commercial Dumbwaiter used to Save manpower, save space, save time, save energy and help avoid workplace injuries. Typical materials handled in a commercial environment can be Food, Dishes & Cutlery, Documents, Clothing, Carts or Shoes. Commercial Dumbwaiter can have one of the following types or configurations: 

Commercial Dumbwaiter Configurations

Forth: Elevators classification according to elevator location  

A- Outdoor Elevators   Common types of outdoor elevators are cargo elevators, platform elevators, and incline and vertical elevators. 

A.1 Observation elevator 

Observation elevator

The observation elevator puts the cab on the outside of the building. 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. 

A.2 Incline Elevators 

Incline Elevators

Outdoor elevators built on an incline can also be used to transport passengers or goods. 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. 

A.3 Platform Elevators 

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. 

A.4 Freight Elevators

Freight Elevators

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. 

B- Indoor elevatorsAll elevators installed inside a building which usually need a hoist ways and pits. 

Fifth: Elevators classification according to special uses  

A- Handicap Elevators  

Handicap Elevators

In reality, any type of elevator that can assist a handicapped person in going up and down various levels of the building could be considered a handicap elevator. However, specific types of elevators are manufactured with handicapped persons in mind. A good example of this would be a wheelchair lift that gets a handicapped person in and out of vans. The lift comes out the sliding doors and descends in order to allow the wheelchair on the platform. Then the lift is raised up and backs into the vehicle. Most city buses have this type of handicap elevators installed on them, but they are also manufactured for privately owned vehicles as well. Most handicap elevators within a home are electric elevators, but some are pneumatic vacuum models as well and operated by air pressure. Stairway lifts are also considered to be a type of handicap elevator and this type can either be installed on a straight stairway or a curved staircase. 

B- Grain Elevators

Grain Elevators

A grain elevator is a tower containing a bucket elevator, which scoops up, elevates, and then uses gravity to deposit grain in a silo or other storage facility. They can be classified as either “country” or “terminal” elevators, with terminal elevators further categorized as inland or export types. Operations other than storage, such as cleaning, drying, and blending, often are performed at elevators. The principal grains and oilseeds handled include wheat, corn, oats, rice, soybeans, and sorghum. 

C- Double-deck elevator  

Double-deck elevatorDouble-deck elevators save time and space in high-occupancy buildings by mounting one car upon another. One car stops at even floors and the other stops at the odd floors. Depending on their destination, passengers can mount one car in the lobby or take an escalator to a landing for the alternate car. 

D- Sky Lobby  

Sky Lobby

In very tall buildings, elevator efficiency can be increased by a system that combines express and local

elevators. The express elevators stop at designated floors called sky lobbies. There, passengers can transfer to local elevators that will take them to their desired floor. By dividing the building into levels served by the express elevators, the local elevators can be stacked to occupy the same shaft space. That way, each zone can be served simultaneously by its own bank of local elevators.

F- Limited use / limited application     (LU/LA)

 Limited use / limited application  (LU/LA)

The limited-use, limited-application (LU/LA) elevator is a special purpose passenger elevator used infrequently, and which is exempt from many commercial regulations and accommodations. For example, a LU/LA is primarily meant to be handicapped accessible, and there might only be room for a single wheelchair and a standing passenger