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Last edited 04 Oct 2019
Building automation usually involves the use of an electronic building management system (BMS) to control and automate mainly heating, ventilation and air conditioning systems but also lighting, access control, energy management, fire alarms and other building services. Commercial, industrial and residential buildings fitted with such systems are often called ‘smart buildings’ or intelligent buildings’ and a house with BAS maybe called a ‘smart home’. Most commercial buildings constructed after 2000 are fitted with a BAS.
Building automation systems (BAS) are distributed control systems where a variety of electronic devices monitor and control mechanical devices which in turn can be commanded to alter the state of an environment at any particular time or at predetermined set times. The user interface – whether for homeowners or building maintenance personnel – displays the system status, detects any possible problems and makes any necessary adjustments. Building facilities managers and home owners can input their required comfort setting into the BMS and the settings will be maintained until commanded to do otherwise.
Typical of the types of control include maintaining room temperature within a specific range at different times; switching lights on and off depending on occupancy; lowering the energy consumption of a building’s water circulation pumps through variable frequency drives; monitoring system performance and, in the event of impending malfunctions, providing notifications via email, text message, mobile voice call and/or an audible alarm to the end user.
Compared to a non-controlled building the benefits of a BAS can include:
- Enhanced occupant comfort and productivity
- Improved operation of systems
- Increased energy efficiency can make buildings ‘greener’.
- Better connectivity and monitoring of systems
- Increased safety
- Maintenance staff can be more efficient and productive
- Lower maintenance costs
- Time savings.
 What are the components of a BAS?
A building automation system’s hardware typically comprises:
- Servers – which run the BAS software through desktop or rack-mounted PCs to collect and serve data.
- Controllers – small, programmable control systems (computers) to control inputs and outputs to air handling, heating and other systems (based on inputs received).
- Field buses – the way field controllers communicate with supervisory devices.
- Supervisory devices – usually installed in dedicated devices and typically have an Ethernet NIC and a field trunk port.
- Inputs – signals from devices such as temperature or pressure sensors.
- Outputs – BAS controller sends a command as an output to say, a relay or actuating device etc.
 Software is also part of a BAS and can include:
- Databases – store information, eg alarms, trends, reports, schedules etc.
- Configuration software – configures servers, other devices and field controllers.
- User interfaces (UI) – installing or downloading applications, using web browsers to access the BAS.
 Potential issues
Cyber security can be a problem: a BAS is not secure as it may feature vulnerabilities which can be exploited by hackers. However, these can be addressed by various controls. It is also possible to increase the security of a BAS by taking the following easy steps:
- Ensuring each user has a unique username and password.
- Ensuring passwords are as complex as possible.
- Use of a firewall
- Closing any unused ports.
 Related articles on Designing Buildings Wiki
- Air conditioning.
- Artificial intelligence.
- BACS building automation controls - the information revolution.
- Building energy efficiency - is building automation the answer?
- Building energy management systems BEMS.
- Building management systems.
- Building services.
- Commercial building automation market.
- Cyber threats to building automation and control systems.
- Energy management and building controls.
- Global building energy management systems market.
- Internet of things.
- Mechanical, electrical and plumbing MEP.
- Parking reservation systems.
- Plant room.
- Smart buildings.
- US Smart Connected HVAC in Commercial Buildings Study 2017.
- Wireless vs wired building energy management system.
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