Notes on the HFC-227 fire extinguisher with the brand name FM200
Information on the HFC-227 fire extinguishing agent under the brand name FM200:
HFC-227 gas is currently being produced and widely used worldwide as one of the cleanest fire extinguishing agents that can be used in the presence of people. Unfortunately, in Iran, due to the weakness of the relevant regulations and standards, the descriptions of the performance and properties of this gas are more from the point of view of advertising and marketing of companies producing and providing it, and some key points related to it are not mentioned. Not considered. In the following, we will express the most important of these cases in a series of related points in order to provide a general conclusion from these cases:
Computationally, in order to extinguish a Class A fire using FM200 gas and the Total Flooding method, the concentration of its combination with ambient air should reach 70,000 PPM or 7%. Also, the allowable concentration of this gas for inhalation without harm to humans is up to 90,000 PPM or 9%.
FM200 gas extinguishes fire with a combination of physical and chemical mechanisms. 80% of its effect is physical (based on heat absorption) and 20% is chemical and based on stopping the rapid oxidation chain of the fuel.
Since the extinguishing operation in this method is based on chemical reaction, if the concentration of FM200 gas decreases from the specified value and due to the presence of sufficient oxygen for the occurrence and regrowth of fire (especially fire hidden and remaining in dense masses of paper The fire is reactivated and due to the vulnerability of the covered material (eg paper documents) against water and hand fire extinguishing powder, practically no operational action by the people present or firefighters to protect the covered material and extinguish. Fire is not possible, as water damage to sensitive equipment is no less than fire.
The design and implementation of such fire extinguishing systems is open loop and no feedback and control mechanism to measure the concentration of gas in the environment and stabilize it in the desired amount is conceivable. For this reason, the calculation of FM200 gas concentration is so-called PreEngineered and is determined based on the calculation of the volume of covered space and the amount of gas storage in the cylinders.
Definitely in a real project and not an academic calculation, it is never possible to seal the covered space and there are many variable physical factors that cause fresh air to enter the covered environment and FM200 gas to leak out and as a result of concentration Predicted to be lower in the original design.
In such cases, the most obvious practical action of engineering in calculations is to consider the safety factor and the margin of confidence. For example, calculate at least 20% of the excess gas under the heading Compensate to ensure the accuracy of future firefighting operations and in the worst case scenario Worst Case.
The key point is the fact that considering this compensation factor, the volume concentration of this gas exceeds the desired range of 7% to the effective level (more than 9% allowed for uncomplicated inhalation in humans). Because the desired amount of 7% per person is a small amount! While other extinguishing agents are designed with high values of concentration and in this regard require less sensitivity and high accuracy of design and execution. In other words, the margin of assurance of the optimal performance of this gas and its adverse effect on individuals is a very small amount of 2%.
According to the MSDS text of FM200 gas (Appendix 1), inhaling higher than defined amounts of this gas will cause respiratory and heart problems for healthy people. And this is especially true for people with heart palpitations and chronic heart and lung problems. (Refer to the HAZARDS IDENTIFICATION section of the technical appendix) Therefore, all designers, specialists and people with experience in this field recommend and instruct people to leave the environment immediately during the FM200 gas discharge instruction!
Another very important point is that apart from the properties of FM200 gas, due to the contact of this gas with high heat and flame and due to the reactions of fuel oxidation chain (fire extinguishing), some toxic gases such as carbon monoxide and all More importantly, HF-Hydrofluric Acid vapors are produced and released into space. This has little effect on small, low-energy fires in server rooms and data centers, but on large, wider flames caused by paper, book, and Class B fires, the rate of production and release into space has been quite effective. And causes very serious and fatal damage to people and equipment covered.
According to the latest research by US Army medical teams on soldiers who were forced to stay indoors in Afghanistan while extinguishing the FM200 fire and practically inhaled the resulting HF-Hydrofluric Acid gas, the initial effect of this inhalation is high. It has not been, but over time, its destructive effects cause necrosis in lung tissues and eventually cause death.
The full text of the medical report can also be downloaded as a technical attachment and its study is recommended to all experts.
Examining the above-mentioned cases and summarizing them, it can be concluded that in any case, firefighting by a clean gas agent is very risky in the presence of working people, and it is not possible to rely on common names and business descriptions to assure personnel that no risk It is not aware of their health. And while informing the people about the features, capabilities and dangers of this system correctly and effectively, it is necessary to mention their main duties in case of fire.
Also, considering the fact that in many projects, a few specific people enter the places covered by the automatic fire extinguishing system, along with the installation of warning signs about the activation of the automatic fire extinguishing system and other preventive safety measures, the final choice. Due to its very high power and efficiency, as well as its lower price compared to the FM200, along with having the ability to test the initial hot and recharge cheaply and easily, it is more suitable and desirable if the option is activated.
In addition, the following effective measures can be taken to prevent any harm to people:
· The alarm sounds in the fire alarm position.
A stronger alarm sounds in the fire extinguishing mode (before gas discharge).
Calculate and adjust the delay time before gas discharge and to ensure the discharge of the environment.
Possibility to deactivate automatic fire extinguishing mechanisms during office hours. (In this case, it is still possible to extinguish the fire automatically and manually with ease and ease)
Installation of visual emergency exit warning from the tank if the system is activated.
· Installation of visual warning not to enter the tank in case of system operation.
Finally, we summarize the non-technical and special cases that are specific to the current situation of the country and should be considered along with the technical points in the decision-making process:
Country-specific non-technical issues that seriously challenge the choice of FM200 gas:
1- Multiple cost of using this gas compared to designing a system based on Co2 gas
2- Impossibility of direct and valid purchase from the main manufacturing companies due to security issues and sanctions.
(Basically, reputable companies supplying this gas and related equipment such as Chemitron – Kidde – DuPont – Ansul are American and due to the strict international technical requirements, first the location maps and geographical location of the site (to calculate the coefficients of atmospheric pressure and altitude from Sea level) and after technical approval of the plan, approve the Approve list and supply equipment)
3- Impossibility of hot test due to impossibility of recharging from the main source (assuming the possibility of initial supply of main gas)
((Hot test is a complete test of the fire detection, alarm and extinguishing system, in such a way that by creating a controlled fire in the place of all defined processes, the system is tested 100% real and its performance is verified))
4- Impossibility of testing the purity and originality of the contents inside the gas tank. (If FM200-like gases are used instead of the original type, the fire extinguishing operation will be performed properly, but the harmful side effects for people as well as protected goods are not under control and there is a possibility of unpredictable life and financial damage. In case of gas contact with flame and high temperature, lethal acidic and toxic gases resulting from chemical reactions are much higher than similar cases caused by the original FM200 and cause damage to the environment and equipment under cover and also cause serious damage and death to people who damage the environment. They have not left.
Any use, exploitation and republishing of the above materials without mentioning the source is unrestricted.