When fire originates in environments with sensitive equipment, flammable materials, or specific risks that water cannot safely combat, chemical fire suppression systems come into play. These are active protection solutions designed to act quickly, effectively, and with the least possible collateral damage to installations.
Understanding how these systems work, what agents they use, and in which situations they are applied is essential to choosing the right protection in each case.
What are chemical agent fire suppression systems?
Chemical agent fire suppression systems are fixed or semi-fixed installations that detect a fire and automatically discharge a chemical extinguishing agent onto the source of the fire. Unlike water or inert gases, chemical agents act by interrupting the chain reactions of combustion at a molecular level, allowing them to extinguish fires very quickly with relatively small amounts of agent.
Their use is especially recommended in:
- Industrial kitchens and environments with oils and fats (Class F fires).
- Machinery rooms, generators, and electrical panels.
- Storage areas for flammable products or combustible liquids.
- Environments where water would cause irreparable damage to equipment.
- Industrial vehicles, heavy machinery, and paint booths.
How do they work? The operating principle
All chemical agent fire suppression systems share an operating scheme based on three phases:
1. Detection
The system includes thermal, rate-of-rise, or fixed temperature detectors that identify the heat generated by the fire. In environments such as industrial kitchens, this type of detection is preferable to smoke detectors, which can trigger false alarms due to steam and greasy aerosols.
2. Activation
Once the established temperature threshold is exceeded, the system activates automatically. In some cases, it can also be manually triggered. Activation simultaneously initiates the shutdown of gas or electrical supply and, where applicable, the closing of ventilation dampers to prevent the spread of fire.
3. Agent discharge
The chemical agent is stored in pressurized cylinders and distributed through a network of pipes to nozzles or diffusers located over risk areas. The discharge covers the fire source uniformly, suppressing flames and preventing re-ignition.
Types of chemical agents used in suppression systems
The effectiveness of a system largely depends on the selected extinguishing agent. The most commonly used in fixed installations are:
1. Wet chemical agent
This is the standard agent for fire suppression in industrial kitchens. It is specifically formulated to combat Class F fires. When it comes into contact with high-temperature oils or fats, it causes a saponification process: it chemically reacts with the grease to form a soapy layer that seals the surface, extinguishes the fire, and prevents re-ignition. It is the only agent recognized by regulations as suitable for this type of fire.
2. ABC and BC dry powder
One of the most versatile agents. It works by interrupting the combustion chain reaction and chemically inhibiting the fire. It is effective against Class A (solids), B (flammable liquids), and C (gases) fires. However, it generates significant contamination in the environment, making it less suitable for spaces with electronic equipment or precision machinery.
3. Alternative halogenated agents (HFCs and FKs)
These are gaseous chemical agents that act mainly by inhibiting the combustion reaction, with an additional cooling component. They leave no residue, do not conduct electricity, and do not damage equipment, making them ideal for server rooms, archives, electrical panels, and environments with high-value equipment. The most commonly used are HFC-227ea (FM-200) and FK-5-1-12 (Novec 1230).
4. Chemical foam (AFFF and AR-AFFF)
Mainly used for Class B fires (flammable liquids). The foam forms a layer over the fuel surface, isolating it from oxygen and preventing vapor evaporation. It is commonly used in fuel storage, hangars, and loading platforms.
Main components of a chemical suppression system
A properly designed system includes the following elements:
- Storage cylinders: contain the extinguishing agent in pressurized or liquid form, ready for discharge.
- Control valves: regulate the release of the agent and can be activated automatically or manually.
- Distribution network: pipes and conduits that carry the agent from the cylinders to the nozzles.
- Nozzles and diffusers: designed to distribute the agent uniformly over the protected area.
- Detection and control panel: manages detector signals and coordinates system activation.
- Shutdown systems: automatically cut off gas or electrical supply when activated.
Criteria for choosing the right system
Selecting the most suitable chemical fire suppression system depends on several factors that must be analyzed before installation:
- Fire class: each agent is designed for specific fire types (A, B, C, F).
- Type of installation: space characteristics, volume, and presence of sensitive equipment influence the choice.
- Acceptable collateral damage: in environments with high-value equipment, residue-free agents are preferred.
- Presence of people: some agents require prior evacuation; others are safe in occupied spaces.
- Applicable regulations: the sector and installation type determine compliance requirements.
- Maintenance and refilling: the lifespan of the agent and maintenance costs vary by type.
Applicable regulations in Spain
Chemical fire suppression systems are subject to a regulatory framework that ensures their safety, effectiveness, and proper maintenance:
- RIPCI — Royal Decree 513/2017
- UNE-EN 15004 — Gaseous fire suppression systems
- UNE 23110 — Portable fire extinguishers
- UNE 23510 and UNE-EN 17446 — Automatic suppression in kitchens
- Regulation (EU) No. 517/2014 — Fluorinated gases
Maintenance of chemical fire suppression systems
A well-designed and installed system only guarantees effectiveness if properly maintained. Spanish regulations establish mandatory periodic inspections including:
- Quarterly inspections of the system’s overall condition.
- Annual inspections of components, pressure, and tightness of cylinders and valves.
- Hydraulic tests and agent refilling according to manufacturer specifications.
- Verification and calibration of detectors and the control panel.
- System adaptation in case of changes in the protected space configuration.
Maintenance must always be carried out by authorized installation and maintenance companies registered in the Security Companies Registry.
Key takeaways on chemical fire suppression systems
Chemical fire suppression systems provide a fast, precise, and risk-adapted response for each installation. Proper design, installation, and maintenance ensure:
- Automatic and immediate response to fire.
- Protection of people, equipment, and facilities.
- Compliance with current fire safety regulations.
- Minimization of collateral damage in the protected environment.
- Prevention of re-ignition thanks to the specific properties of each agent.
Choosing the right agent and system, properly sizing the installation, and carrying out periodic maintenance are the three pillars of real and effective fire protection.