Fire alarms are essential safety systems in commercial buildings that alert building occupants and emergency responders to the presence of a fire. Fire alarms can be classified into several categories based on the type of building they are used in, the type of fire they are designed to detect, and the type of alert they provide.

1. Conventional fire alarms: Conventional fire alarms are the most basic type of fire alarm system. They consist of a series of interconnected smoke detectors and manual pull stations that are wired to a central control panel. When one of the detectors or manual stations is activated, it sends a signal to the control panel, which then triggers the alarm. Conventional fire alarms are suitable for small buildings with a simple layout, but they can be less reliable in larger buildings with complex layouts because they rely on hardwired connections between the components.
2. Addressable fire alarms: Addressable fire alarms are more advanced than conventional fire alarms because they can identify the specific location of a fire within a building. Each smoke detector and manual pull station in an addressable fire alarm system is connected to the control panel via a digital communication network. When a detector or manual station is activated, it sends a signal to the control panel with its unique address, allowing the control panel to determine the exact location of the fire. Addressable fire alarms are more expensive than conventional fire alarms, but they are more reliable and easier to maintain because they can be programmed and tested remotely.
3. Radio-frequency (RF) fire alarms: RF fire alarms use wireless technology to communicate between the detectors, manual stations, and control panel. This type of fire alarm is ideal for buildings with complex layouts or where it is difficult to run hardwired connections between the components. RF fire alarms are also useful in temporary or portable buildings, such as tents or trailers, where it is not practical to install hardwired systems.
4. Autonomous fire alarms: Autonomous fire alarms are self-contained units that are not connected to a central control panel. They are typically used in small buildings or isolated areas where it is not practical to install a full fire alarm system. Autonomous fire alarms typically consist of a smoke detector and an alarm horn or strobe light. When the smoke detector is activated, it triggers the alarm horn or strobe light to alert building occupants to the presence of a fire.
5. Fire suppression systems: Fire suppression systems are designed to extinguish fires before they can spread. They can be classified into several categories based on the type of fire they are designed to extinguish and the type of suppression agent they use. Common types of fire suppression systems include sprinkler systems, foam systems, and gas systems.
6. Emergency evacuation systems: Emergency evacuation systems are used to alert building occupants to the presence of a fire and instruct them on how to safely evacuate the building. They typically consist of a series of alarms, speakers, and visual indicators that are activated when a fire is detected. Emergency evacuation systems can be stand-alone systems or integrated with other fire alarm systems.

In conclusion, there are several categories of fire alarm systems that are used in commercial buildings. The type of system that is best for a particular building depends on the size and layout of the building, the type of fire it is designed to detect, and the level of protection it provides. It is important to carefully consider the needs of the building and the occupants when selecting a fire alarm system to ensure that it provides the necessary level of protection.