Integration: Building automation and fire alarms

The building automation system can control all aspects of a building or campus, including its fire alarm system. This outlines best practices for integrating a fire alarm into a BAS.

08/22/2013


Learning objectives

  1. Understand the efficiencies of integrating building automation with fire protection systems.
  2. Name various communication protocols, such as BACnet and LonTalk.
  3. Learn about inspection and testing of systems.

Figure 1: This modular building controller containing open processors gateways with communication drivers is used when integrating building automation systems with other equipment communicating over a multitude of communications protocols. Courtesy: SiemeThe responsibilities of a chief building engineer are becoming more challenging as technology advances. Bigger and taller buildings are being constructed with an increasing emphasis on energy efficiency and comfort, and the ever-increasing demand to keep construction costs and operating expenses down. In addition, building codes are changing the way these buildings are constructed in order to improve safety with an eye on new construction methods and materials.

There is also the somewhat traditional mind-set among those within the design and engineering community that building automation and fire alarm systems should maintain a significant level of separation with minimal connectivity or interaction. Most of this belief stems from the fear of the unknown and the desire to mitigate risk along with the old adage of "This is the way we've always done it." In reality, the integration of building automation and fire alarm systems can result in overall reduction in equipment, installation, and maintenance costs while still maintaining the level of safety required for these systems to operate. 

With the advent of smart building technology, heating, cooling, electrical, lighting, security, and other systems need monitoring and intercommunication for optimized efficiency and operation. With sophistication comes the need for a building automation system (BAS) to allow for nearly seamless operation of these various interrelated equipment. 

Like BAS, fire protection and alarm systems have also evolved into sophisticated computer-based systems, which integrate fire detection and emergency communication systems as part of overall building operations during an emergency event.

Often fire protection and alarm systems must interact with other building systems to provide a proper level of protection. While the fire alarm system is fully capable of performing and initiating the necessary actions to accomplish the fire alarm and building systems’ responses, efficiencies can be obtained by integrating with the BAS. These efficiencies include minimizing additional equipment, expediting system acceptance testing, reducing installation costs, and sharing and consolidating information at a central location where all of the building systems can be precisely monitored during emergency incidents.

Smoke control systems are a good example of the marriage of building mechanical systems with fire protection/fire alarm systems. Fans are starting or stopping, dampers are opening or closing, and doors may be closing or unlocking while elevators being recalled. Although both the BAS and fire alarm systems have specific tasks to perform, there is a certain level of priority and sequences that must be followed. Failure to follow the proper priority or sequence may not only be non-code compliant, it may also lead to equipment damage or risk to human life. For example, if a smoke control fan operates before dampers open, ductwork may be damaged or door opening forces may be increased beyond acceptable levels for egress.

Communication

When the fire alarm system takes control of equipment that is not a listed component of the fire alarm control unit, the fire alarm system must either override the natural operating mode of the building equipment or pass off that command via a simple switch or data communications to the building mechanical systems. Likewise, each manufacturer’s BAS has its own protocol for monitoring conditions and communicating operational commands to maintain the proper building environment and efficiency. There are also standard open communication protocols such as LonTalk and BACnet that can be used to communicate with a multitude of equipment from various manufacturers in order to achieve an integrated building system. 

The communication protocol for a fire alarm control unit to communicate to and from its indicating (input), initiating (output), and sometimes notification appliances is typically an analog or digital communications signal carried over what is referred to as a signaling line circuit (SLC). Because communications signals are typically proprietary protocol, each SLC is dedicated to a specific manufacturer’s equipment and cannot include connection of incompatible devices that use a different signal protocol. 

Therefore, in order to integrate system alarm and control functions with the BAS in a manner other than relay logic, fire alarm system manufacturers had to also design and support the open communication protocols used for building automation, in a manner that would not compromise the integrity or the operation of the fire alarm system. This process of sharing information between both fire alarm and BAS came to be known as bridging, or open gateway processing. Because of the strict code and listing requirements of fire alarm systems, much of this communication has been primarily limited to one-way communication. However, some manufacturers of both fire alarm and BAS do produce equipment such as gateways that are listed for bi-directional communication with their equipment. 

The use of these open gateway processors has the potential to eliminate the need for costly interface equipment and enclosures. A single gateway can replace hundreds of conventional or electronic relays and input sensors for control and monitoring while also eliminating the need for multiple wire terminations that can decrease the potential for system failure points.


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Anonymous , 09/13/13 09:35 AM:

Putting a conventional addressable fire alarm system online in a highrise is an extremely involved procedure. There is no way adding several more levels of system control into the FACP will make system programming and acceptance testing go faster. The hackers out there can already get into your BAS. This way you give them access to your life safety systems also.