Eaton PLC: Savings Lives And Properties

In 1980, there were 10,570 structural fires in office properties. However, between 2007 and 2011, the average number of structural fires annually was only 3,340. The drastic decrease in the number of office building structural fires may be contributed to advancements in the technology of fire and life safety systems. One of the most intriguing of these technological advancements is the programmable logic controller.

If you manage an office building that has not yet been retrofitted with the newest technology, you may be wondering what a programmable logic controller does in a fire and life safety system. The programmable logic controller, or PLC for short, is the computer system that controls when to shut down mechanical and electrical systems and turns on sprinklers and ventilation systems. Here's what a PLC does.

Recognizes dangerous levels of heat and smoke

Sensors that detect heat and smoke are located throughout the building. The readings from the sensors are monitored by the PLC. Once the readings become too high when heat and/or smoke are detected, the PLC uses logic to determine if, when, and where there is a fire. The computer system then shuts down and turns on various systems simultaneously to prevent the fire from spreading throughout the building, begin fire suppression, and save lives.

Shuts down electrical circuitry, elevators, and other systems

Depending on the location of the fire and/or smoke, the PLC may shut down the entire electrical circuitry of the building or just a section of it. The PLC is programmed to recognize the needs to save life and property within the building based on the location of the problem.

Elevators are immediately taken to the ground level and shut down with the doors opened. This is one of the life saving aspects of the system. It prevents people who are trying to escape the building from getting trapped in an elevator.

All necessary mechanical systems within the building are also shut down, including computer systems. In industrial or manufacturing facilities, the mechanical systems are also shut down.

Turns on sprinklers, emergency lighting and ventilation systems

At the same time, other systems are being turned on. Sprinklers above and nearest to the fire immediately douse the flames. The emergency lighting system turns on so people who are exiting the building can see their way out.

The ventilation system is also controlled by the PLC. The dampers of the HVAC system are closed. This prevents the smoke from getting into the ducts and spreading to the rest of the building.

Large fans in the stairwells turn on to pressurize the air so the smoke cannot get into the stairwells and choke people who are escaping. Smoke sensors located in the stairwells can tell the PLC when the fan speed should be increased or reduced for optimal pressurization.

The alarms on the fire escape doors are turned off to allow for people to safely escape. The doors are unlocked to allow firefighters to gain entrance into the building.

Alerts the fire department and other authorities

The computer system alerts the fire department and important personnel, such as the general manager and building owner.  The fire and life safety system is designed to inform the fire department of the size and location of the fire and it's status, based on the readings the computer system receives from the sensors.

The brain of the fire and life safety system in an office building is the programmable logic controller. This advancement in technology has software that is programmed by a computer specialist who is certified by the state to design and install these all-encompassing systems. To learn more about the abilities of a programmable logic controller to improve your business, visit