Aerosol Fire Suppression Systems – The Facts about Safety
Special Hazards is a complex area of fire protection, often overlooked by mainstream science and engineering disciplines. It involves dozens of different technologies aimed at fire detection, fire suppression and system controls in high value technology and industrial facilities. One such technology is the dispersal of aerosols, in a total flooding configuration, for fire suppression. Use of aerosols in this application is relatively new and is often misunderstood.
Aerosols used for fire suppression applications are, in most cases, referred to as condensed aerosols. Prior to activation, they take the form of a dense pellet-like compound, housed in a larger metal container. The container is typically fitted with orifice holes that function as a nozzle. When activated, a reaction occurs releasing ultra-fine particles that fill the protected space, and react chemically with a fire to suppress, and in most cases extinguish it.
Many people think ‘cooking-spray’ or ‘hair-spray’ when hearing the word aerosols. In fact, these two forms of aerosols are very different. Typical household aerosol products involve a liquid that is emulsified and propelled into the air though the use of a propellent in a pressurized container, such as propane, nitrous oxide, or carbon dioxide. The primary differences are the form in which they are dispersed (fine particles vs. liquid) and the method of dispersal (chemical reaction vs. pressurized propellent).
The short answer is, definitely not! Each manufacturer’s condensed aerosol pellet is made up of a proprietary mixture of chemical compounds specifically designed to disperse into the protected space, and react chemically with the fire, to suppress and extinguish it. Some are more efficient than others, evidenced by the manufacturer’s recommended design density, measured in grams of aerosol per cubic meter of space. The Stat-X® UL listed condensed aerosol suppression system has the lowest design density for class A (surface), B and C hazards of any internationally recognized aerosol system available today. Further, Stat-X generators are the first to attain UL listing for use in Class I, division 2 hazardous areas.
As with most fire suppression systems, when designed, installed, and maintained properly, the systems are safe. At least 2 condensed aerosol products, including Stat-X, are listed on the USEPA SNAP list, and approved for use in normally occupied spaces. It is important to under stand that ALL special hazard fire suppression systems (clean agents, inert gases, water mist, dry chemical, wet chemical, aerosols, etc…) are inherently complex multi-component systems that require careful design, trained and experienced installers, and maintenance over the course of the system life. Any indication or suggestion that one system is significantly more dangerous than another is at best misleading, at worst simply untrue.
Condensed aerosols discharge ultra-fine particulates, that will tend to settle in the space, post event. However, nearly all special hazard systems will create a particulate layer post discharge due to smoke from the fire and the high pressure discharge of inert gases, HFC’s or fluorinated ketones, which tend to dislodge dust and other particulates in the protected space. The result in all cases is a need for clean-up. Nobel provides simple procedures for an effective clean up that support minimal disruption or downtime. Remember, all special hazard fire suppression systems, when activated, will require some level of clean-up.
Condensed aerosols for fire suppression can be used in a wide variety of special hazard applications. Some applications that are particularly well suited for Stat-X systems are:
- Energy Storage Systems
- Machinery Spaces
- Electrical Cabinets
- Wind Turbine Nacelles, Cabinets and Transformers
- Heavy Vehicle / Rail / Marine Engine Spaces
- Generator Sets, Rooms or Facilities
Aerosol fire suppression agents can remain effective in areas that cannot be made completely gas tight. Due to their natural buoyancy, aerosols can have longer total flooding retention times than gaseous agents.
As with all fire suppression systems, some are better suited that others for specific applications. Condensed aerosol systems are ideal for industrial and electrical hazards. Aerosols are used less frequently in residential or commercial applications where water based, traditional sprinklers may be the option of choice.
Transportation of condensed aerosol canisters is governed by the point of origin for shipment, and the classification of the product. Stat-X generators may be shipped from the US as Class 9packaged goods based on Fireaway's special permit (SP20600) issued by the US Department of Transportation. Other similar products may be classified as 1.4S or other, depending on the material in the aerosol pellet and any local government regulations. Always check with local authorities to determine any potential requirements for shipment of Stat-X generators.