At the same time, fire has been an indispensable element and a potential traditional enemy of human dwellings and workplaces.
Since ancient times, cities have always had a variety of more or less sophisticated means for fighting accidental fires, traditionally with fire departments that were entrusted with this task. At the beginning of the 20th century, mechanical fire safety system began to be installed to detect and extinguish fires based on water storage and its automatic or manual discharge in an emergency.
Fire protection installations in certain types of buildings require the storage and distribution of water to points close to the inhabited areas for use in the event of an accidental fire. Such fire safety systems, by definition, keep the water stagnant until the time of service. From a risk point of view, there are several types of potential problems listed in order of importance:
- The fire safety system is connected (without adequate cutoff protection) to other water
- The fire-fighting installation is connected (without adequate shut-off protection) to additional water storage and distribution networks that may be contaminated if bacteria develop in the fire-fighting network.
- In the fire-fighting network.
- The fire fighting installation is contaminated by Legionella pneumonia type bacteria, and workers and users are potentially exposed during the execution of hydraulic tests.
- The fire fighting installation is contaminated by Legionella pneumophila bacteria, and workers and users are potentially exposed during the use of the equipment in an emergency.
The fire safety system is a set of diverse equipment integrated into the structure of the buildings. Currently, the characteristics of these systems are regulated by the building code. Fire protection is based on two types of measures:
- Passive protection measures.
- Active protection measures.
Passive protection measures:
These are measures that try to minimize the harmful effects of fire once it has occurred. They aim to limit the distribution of flames and smoke throughout the building and allow an orderly and rapid evacuation of the building.
Some examples of these measures are:
- Dampers on air ducts.
- Coating of structures (to maximize the time before collapse due to temperature deformation).
- Fire doors.
- Dimensions and characteristics of escape routes.
- Emergency signaling and lighting.
- Compartmentalization of fire sectors.
Active protection measures:
These are measures designed to ensure the extinction of any fire outbreak as quickly as possible and thus prevent its spread in the building. Within this section, two types of measures are considered:
- Fire detection measures are usually based on smoke detection (ionic or optical) or temperature rise.
- Fire extinguishing efforts, which can be manual or automatic:
Manual: Extinguishers, Equipped fire hydrants (BIE), Hydrants, Dry column.
Automatic: Equipped with systems of different extinguishing products: – Water (Sprinklers, water curtains, foams, water spray). – Gases (Halons (currently in disuse), carbon dioxide). – Dust (every day or polyvalent).
Within all this set of equipment and facilities, from the point of view of legionellosis, only those equipment that accumulates water and can spray it at some point, either in tests or in case of a real emergency, present a risk. Specifically, we must include the facilities with the risk of legionellosis the manual fire extinguishing measures equipped with water, such as prepared fire hydrants (BIE) and hydrants. Automatic systems use water for killing, such as sprinklers, water curtains, or water spray systems. The structure of the risk systems, both in manual and automatic installations, is similar; they have a water supply system, a water storage tank, and a group of pumps (often with autonomous electrical power supply) or direct input from the supply network. Depending on the premises’ uses and dimensions, there are specific regulatory requirements regarding the obligation to maintain a particular volume of stored water in case of emergency. This fact is the leading risk from the point of view of legionellosis, keeping water stored typically very long for some time. At a particular moment, it can be sprayed in the presence of people.