A fire protection system is made up of diverse systems that work together to detect, alert, suppress, contain, and ventilate. So, let’s break down each of these types of fire protection systems in detail, how they work, when they are used, and why they are important in maintaining fire safety.

Fire Alarm System

The primary purpose of a fire alarm system is to detect the early signs of fire and alert the occupants to evacuate immediately whenever the fire breaks out. They often trigger other fire protection equipment, such as fire sprinklers and emergency communication. The key components of a fire alarm system include smoke alarms, heat detectors, a manual pull station, and a fire alarm control panel. Here are simple definitions of each of these components:

• Smoke detectors are triggered by the particles in the air caused by combustion. 

• Heat detectors respond to high temperature or a sudden rise in temperature. 

• Manual pull stations allow the occupants to activate the alarm manually. 

• The control panel is the brain of the fire alarm system. It processes the signals and triggers responses. 

Furthermore, a fire alarm system can be either addressable or conventional. In a conventional fire alarm system, zones of the building are wired in groups, and when a detector activates, one can identify the general area where the fire has occurred. But in addressable fire alarm systems, each device has a unique ID, and when fire occurs in a part of a large building, it pinpoints the exact location of the fire.

Automatic Fire Sprinkler System

A fire sprinkler system automatically discharges water when heat is detected. The threshold temperature needs to be around 155°F or 68°C near the sprinkler head. There are usually four types of sprinkler systems: dry, wet, pre-action, and deluge.

Wet pipe systems are most commonly used in the United States, and the pipes are always filled with water, and they discharge water as soon as they activate. Dry pipe systems are mostly used in cold environments, and the pipes are filled with pressurized air so that the water doesn’t freeze inside the pipe. When the sprinkler activates, the air escapes, and water is discharged. In deluge systems, all sprinklers are open, and a valve holds back the water. When fire occurs, the sprinkler activates all at once. The pre-action system is a mix of wet and dry-pipe systems, and it activates only when the fire is confirmed. 

Fire Suppression System

In special-hazard environments like server rooms, electrical panels, etc, water causes more damage than the fire itself. In such cases, fire suppression systems are used to control and extinguish fire by using agents other than water. There are four types of fire suppression systems:

• Clean agent systems use gases such as FM-200 or Novec 1230 to suppress fire without leaving a residue or water damage. It is most commonly used in IT rooms, the control room, and medical facilities. 

• CO₂ suppression systems extinguish fire by displacing oxygen, and they are common in engine rooms, electrical vaults, etc. However, they are not safe for occupied spaces due to fire risk. 

• Foam systems create a blanket over flammable liquids and cut off the oxygen.

• Water mist systems use ultra-fine water droplets to cool flames and displace oxygen.

Smoke Control and Ventilation System

Smoke control and ventilation systems keep the exit paths clear, prevent smoke from traveling, and help firefighters. Some of the common smoke control components are smoke exhaust fans that remove smoke from fire zones, pressurization systems that maintain higher air pressure in stairwells to prevent smoke infiltration, and smoke dampers that automatically close to confine the smoke in specific areas.

Fire Extinguisher

Fire extinguishers are the first line of defense against fire and are a critical part of active fire protection, especially in the early stages of fire. There are various classes of fire extinguishers, like Class A, Class B, Class C, Class D, and Class K. And before choosing a fire extinguisher, you need to know which kind of fire you are dealing with. If a combustible material like paper, wood, trash, etc., is burning, then you should use a Class A fire extinguisher, if it is a electrical equipment then you must use Class C one, but if it is high-temperature fires such as cooking oils and fats, then you have to use a Class K extinguisher.

NFPA 10 standards define the sizing and placement of fire extinguishers, and they must be mounted in visible and accessible locations. For example, in occupancy with lower fire risk, such as schools, a 2A-rated fire extinguisher should be placed within 75 feet. According to the fire codes and standards, a fire protection professional must inspect the fire extinguisher annually, and it must undergo hydrostatic testing every 5-12 years, depending on the type.

Passive Fire Protection System

The primary purpose of passive fire protection equipment is to hold the fire for a specific period of time, giving the building occupants time to evacuate and the emergency responders time to act. According to the IBC (International Building Code) and NFPA 101 (Life Safety Code), passive fire protection systems must be installed, especially in hospitals, schools, high-rise buildings, and industrial facilities. Let’s go through the key elements of a passive fire protection system:

Fire-Resistant Construction Materials

The fire-resistant construction materials resist heat and prevent structural collapse for a particular period of time. Some of the assemblies, such as fire-rated walls, ceilings, and floors, are made from fire-rated gypsum boards, autoclaved aerated concrete (AAC), or reinforced ceilings and are tested to resist fire for 1 to 4 hours. 

Compartmentalization

Compartmentalization prevents the fire from leaping from room to room. The buildings are divided into fire zones using fire-rated floors, ceilings, and walls that confine the fire and the smoke to a limited area. And these fire partitions not only resist flame but also stop the smoke from travelling, which is very important as more than 50% of the fire deaths are caused by inhalation of smoke. 

Firestopping

Every building has dozens of pipes, cables, ducts, and data lines, and these areas are the weakest points of the walls because fire spreads fastest through these small gaps. Intumescent sealants and collars expand with heat and seal off the gaps that are created by plumbing and electrical systems. Additionally, one can also use firestop pillows and mortars for larger openings or cable trays in data centers and mechanical rooms. 

Fire Doors and Dampers

Fire doors and dampers are designed to automatically close during a fire. 

Fire doors are made of materials like steel or composite wood and are rated from 20 minutes to 3 hours. They are connected to fire alarms or smoke detectors, and when any smoke is detected, they auto-close and protect the exit routes and stairwells. 

Fire and smoke dampers are located in the HVAC ducts. They close whenever smoke or heat detectors activate, thus preventing fire from traveling through air systems.