Building automation systems (BAS) can monitor and control numerous applications in large residential, commercial and industrial structures. They can be built into the original building’s design, or they can be retrofitted to an existing building in some cases.BAS componentsThe BAS has several key components: sensors, communication, a power source and a control panel of some sort. Depending on the specific installation, there may be multiple access points, but at the minimum, a fire alarm control panel (FACP) is included. The FACP is installed so that firefighters can quickly locate fires and access elevators, doors and other important controls.Strain gauges can be used in comprehensive structural monitoring. Source: Crisitan V./CC BY 4.0 DEEDThe sensors can relay all sorts of data back to the control panel. Many sensors are hardwired, while others rely on a wireless communication protocol, such as Wi-Fi or Bluetooth to reach the control panel. Wired sensors are less likely to be interrupted by large, metal structures, like HVAC equipment, than wireless ones, but wireless sensors can sometimes communicate data when wires are broken, such as after an earthquake or during a fire.To effectively power a BAS, both commercial and backup power systems must be implemented. In most cases, local, state and federal code requires FACPs to have a backup power source, such as a battery bank, so that if the power is turned off, firefighters can still receive the proper information.Purposes of a BASA fully integrated BAS is capable of collecting, processing and archiving data as well as controlling a variety of building functions, all from one set of controllers. For example, at first glance, a fire alarm system does not have much in common with an automated HVAC system. However, during a fire, it might be advantageous to turn off certain fans and close dampers to prevent the spreading of smoke and sparks into other parts of the building.The primary purposes of a BAS are for access control, monitoring utilities, fire and emergency services, ventilation, structural monitoring and a few others.Access controlOne common use of a BAS in commercial and residential buildings is to limit access to certain areas of the building. This can mean placing a badge reader or card swipe on certain doors, security cameras to track who uses spaces, or sensors to determine when doors and windows have been opened. The industrial building’s security personnel can monitor these controls, receiving an alert for any excursions, such as doors opening at unusual times.Utilities monitoringA BAS can also be used to monitor the status of utility parameters. Power input to the building, including power factor for industrial sites, are commonly monitored. The most common utilities, including power, water and sewer, natural gas, as well as wired internet, compressed air or steam, can all be monitored.Also, numerous other types of data can be gathered, depending on what types of sensors are available. Some BAS can be used to monitor current and voltage to the elevators, looking for anomalies that might indicate upcoming service needs, such as bearing replacement on the motors.Fire and emergency servicesPerhaps the most fundamental BAS task is monitoring the fire detection and control system for the building. By code, any large building will have numerous sprinkler heads, smoke detectors, heat detectors and other sensors that are capable of sending an alarm signal to the FACP. These sensors and the controller are equipped with a backup source of power, and often have “watchdog” functions that look for low power, low water pressure or other problems. This allows the BAS to perform a “self-check” to ensure that, in the event of a fire, the system is ready to respond.Besides operating sprinkler heads, the fire control system can close fire doors, and lock out elevators. It can also open vents, close dampers and change the status of HVAC equipment to move sparks and smoke away from those who are evacuating.VentilationVentilation control can be integrated into a BAS. The BAS will then monitor the temperature of rooms to open and close vents accordingly. When combined with access control, or occupancy sensors, ventilation systems can adjust the temperature based on whether the room is occupied. Instead of heating a bunch of empty rooms, the HVAC system will redirect heat to occupied rooms. All rooms are temperature controlled to prevent them from being uncomfortable, should people enter the room, but they are not set to heat and cool to the same temperature as occupied rooms. Likewise, extra cooling might be required for a stuffy conference room, and so conditioned air from unoccupied offices can be directed into the conference room instead.Furthermore, there are many applications that require all of the air to be changed in a room at a certain rate. For maximum cleanliness, operating rooms and some other sensitive hospital spaces must not allow air to become stagnant. Also, these spaces are often placed under positive air pressure, so that when the doors are opened, air rushes out of the room instead of into it, potentially bringing contaminants into the space. Air flow sensors and pressure sensors can monitor this, while the BAS archives and maintains the proper airflow.Structural monitoringDuring the construction of new buildings, a sensor network can be installed that will monitor the structural integrity of the building. Strain gauges in key locations can be embedded in floors, foundations, columns, elevator shafts and other places. The data collected on these is fed back to the BAS.For the most part, structural monitoring sits quietly without much interesting data to report. However, natural and man-made disasters, such as earthquakes and bombings, can lead to structural damage. Sometimes, this damage is hidden from view such that an inspector may not be able to spot it. With embedded strain gauges, the inspector can focus their efforts on finding where damage may be hidden.Final thoughtsWhile some form of BAS has always existed in construction, the low cost of sensors and the ever-improving controllers and algorithms are making BAS design and installation a growing field. Automation system suppliers are now experimenting with using artificial intelligence (AI) modules to help.
Building automation systems (BAS) can monitor and control numerous applications in large residential, commercial and industrial structures. They can be built into the original building’s design, or they can be retrofitted to an existing building in some cases.