International. The School of Integral Safety and Fire Engineering – ESSIIF, analyzed and offered a series of recommendations for the prevention and reaction of fires in cooling towers. Here's your analysis.
The school argued that cooling towers are a special risk within the industrial field, since in many cases, being considered a wet element, their dangerousness is obviated and the necessary prevention and protection measures are not executed.
It must be understood that these towers can contain a variety of combustible materials, including PVC, GRP, ABS or polypropylene in different elements: housings, fan blades, nozzles, blinds, etc. In addition, its own configuration complicates access to the interior elements of the tower in case of fire.
Knowing this, protection must be defined in a transversal way.
The first point of the prevention and protection of these elements is related to the materials that make up its construction, taking into account that the use of non-combustible materials substantially reduces the risk of fire and its spread. Such is the case, that NFPA 214, a reference standard dedicated to the protection of these elements, does not require protection in case all the materials that make up the cooling tower are non-combustible. It must be considered that there are towers on the market approved and certified by FM, complying with different standards of incombustibility and safety.
If protection is required, the installed systems must guarantee precocity and efficiency, taking into account that, if the fire develops completely inside the tower, the access of firefighters and emergency brigades with manual means will be very limited.
As for automatic extinguishing systems, there are several options, such as the use of closed sprinkler systems or the use of deluge systems with sprayed water (meeting criteria of NFPA 214, FM 1-6 or EN 12845 as the case may be). For example, NFPA 214 indicates that the design density in the protection under the fan blades will be at least 20.4 l/min/m2 or 13.45 l/min/m2, depending on whether we protect a tower from counterflow or cross-flow. For its part, the density on the filling material will be at least 20.4 l/min/m2.
It will also be necessary to protect other elements that are not within the range of action of the previous systems, such as fan motors. In addition, action must be taken to stop these fans in case the fire protection systems come into operation.
The use of hydrants and equipped fire hydrants/hoses will serve as a complement to automatic extinguishing systems.
In short, cooling towers, along with other elements such as conveyor belts, are forgotten equipment on certain occasions within the protection of the industrial environment. This sometimes occurs in countries such as Spain, where the regulations address industrial protection in a general way, without entering into the specific definition of equipment and processes.
* The Higher School of Integral Safety and Fire Engineering - ESSIIF is the first distance learning school in Spain specialized in Fire Protection and Safety in all its areas, teaching specific courses and higher programs.
