Actuation
AFEX systems can be actuated both manually and automatically.
MANUAL SYSTEMS:
Manual only systems are a reliable fire protection solution for equipment and a lower-cost alternative to automatic systems. Manual systems are suitable for many types of equipment, but they do lack automatic detection and actuation hardware of other systems.
Manual systems are dependent on the equipment operator to visually detect a fire and take the proper steps to manually actuate the system.
AUTOMATIC SYSTEMS:
Automatic systems feature a detection circuit that senses elevated heat in the protected areas of the vehicle and then automatically initiates the discharge sequence. In addition to automatic actuation, all systems have the ability to be manually actuated by the operator of the equipment by using the firing mechanism. Automatic systems are strongly recommended for equipment that needs protection in areas such as the engine, behind the operator, and out of the operator's line of sight. Automatic systems are also effective in helping fight fires that may start within the first hour following shutdown. This is a common risk for equipment that handles or creates excessive, combustible debris. In this situation an automatic system protects equipment even without the fire being observed.
SPECIAL FEATURES:
REMOTE ACTUATION: AFEX offers the option of adding additional points of manual discharge in the form of seperate remote actuators that allow a person to start the system in situations where the firing mechanism or manual actuator is unreachable. NFPA recommends a seperate, remote point of actuation near the path of egress.
SIDE-CARTRIDGE DESIGN: Due to the harsh environments in which heavy equipment operates, it is essential to ensure that a fire suppression system maintains appropriate pressure levels and avoids compaction. If either of these conditions occur, the system may not discharge.That's why the AFEX Vehicle Fire Suppression system uses a side-cartridge system design to reduce the risk of pressure loss or compaction.
The agent is stored in a non-pressurized tank, and a separate cartridge contains the compressed nitrogen gas. In the event of a fire the system is actuated automatically upon fire detection, or manually by the vehicle operator. The actuation releases the compressed nitrogen and the tank is momentarily pressurized to discharge the agent.