FK 5.1.12
A 'chemical' extinguishing agent can also be used to extinguish the fire in a fairly environmentally friendly manner where the extinguishing agent must not cause damage and where people present must not be endangered.
This can be done by using the extinguishing agent FK 5.1.12.
FK 5.1.12 only has a GWP (Global Warming Potential - value that expresses influence on the increase of the greenhouse effect) of 1. This is the same GWP as that of CO2. By comparison, the GWP of HFC227ea or FM200® is 2 900.
FK 5.1.12 is a chemical substance that belongs to the group of fluoroketones. Its extinguishing effect is mainly based on the strong cooling effect and the extraction of heat from the fire. The FK 5.1.12-air mixture has a much higher heat capacity than pure air. This means that this gas mixture will absorb more energy (heat) for every degree of temperature increase it undergoes. With a correctly chosen design concentration, an amount of heat will be extracted that is sufficient to disrupt the equilibrium within the fire triangle.
Only a small volume concentration is required to control the fire (for computer rooms: 4.7% FK 5.1.12 according to NFPA rule no. 2001 (as “Class C Fires”) and 5.6% according to (NBN) EN 15004-2 “Higher hazard Class A”.
FK 5.1.12 behaves like a gas although it is a liquid under atmospheric conditions of temperature and pressure. The rules stipulate that 95% of the weight of extinguishing agent must have flowed out within 10 seconds after the start of the extinguishing. This obligation applies to all 'chemical' extinguishing gases to prevent the formation of inadmissible quantities of very harmful decomposition products, such as hydrogen fluoride (HF), when exposed to high heat. The extinguishing conditions are therefore quickly achieved.
For inert gases, 95% of the design concentration must be reached within 60 or 120 seconds.
The storage of the extinguishing agent, which takes place in one or more reservoirs, is less extensive than that of an extinguishing system with inert gas. Since FK 5.1.12 is a liquid, a greater weight can be stored in less space. Sometimes the floor load is a problem. This is easier to solve if you choose FK 5.1.12. The location where the FK 5.1.12 is to be stored must be close to the area to be protected. This is in contrast to the storage of inert gas, for which a large distance between reservoirs and the area to be protected is rarely an obstacle.
The mixture that the FK 5.1.12 forms with the air from the room is heavier than the mixture that would be obtained with the inert gas IG55. As a result, the influence of 'leaks' in the 'envelope' of the room is greater with FK 5.1.12. The airtightness must be better to meet the requirement that the extinguishing conditions must be maintained for at least 10 minutes.
When any chemical extinguishing agent, such as FK 5.1.12, escapes, an underpressure will first develop in the room, which then changes into an overpressure. With FK 5.1.12, the negative pressure is much more important than the negative pressure. To ensure that the underpressure does not exceed what is permissible for the construction, arrangements must be made and one or more valves must be provided in the wall to keep this underpressure limited.