The foam extinguishers consist of a sheet steel tank whose charge is composed of foaming liquid diluted in water in a percentage of 3 to 10% and can be used on outbreaks of class A and B. The extinguishing action of the foaming liquid is caused by suffocation (separation of fuel from the comburent) and by minimization of cooling.
They are mostly used for fires of flammable liquids (class B), while the extinguishing effect on class A fires (solid with embers) is low. And they are not to be used on electrical equipment and on class D fires. This is vital in Firefighter Recruitment Perth
The number of extinguishers to be installed is determined only in some specific rules and for some places (schools, hospitals li, hotels, public entertainment venues, garages, etc.). In other cases, the criterion must be made to dispose these first intervention means so that they are readily available and usable.
In principle, the position must be chosen favoring ease of access, visibility and the possibility that at least one of these can be reached with a path not exceeding 15 m. The distance between groups of fire extinguishers must be about 30 m.
Referring to the reading of the document regarding further details on the fire extinguishers, we report some brief information on the firefighting system and hydrants.
Also, in this case the fire extinguishers must have an indication of their suitability for use on live electrical equipment and are considered hazardous against class F fires. In addition, CO2 extinguishing means are not suitable for class A outbreaks in that the gas produces only a momentary lowering of the temperature without the inhibition of the embers produced by the fire. After the discharge the fire would be triggered again.
The fire-fighting water network can be connected directly, or by means of a disjunction pool, to the city aqueduct. The presence of the water reserve is necessary if the aqueduct does not guarantee continuity of supply and sufficient pressure. In this second case, the hydraulic characteristics required to the regulators (UNI 45 or UNI 70 hydrants) are ensured in terms of flow rate and pressure from the capacity of the water reservoir and the pumping unit.
Regarding the hydrants we can have a wall hydrant: fire-fighting equipment consisting essentially of a box (or a protective door), pipe support, manual shut-off valve, flexible pipe complete with fittings, dispensing spout. Firefighter Recruitment Perth applicants must know this information.
High column hydrant: fire-fighting apparatus, permanently connected to a water supply network, consisting of a valve housed in the buried part of the apparatus, operated through a vertical shaft that rotates in the cylindrical body, in which one or more are also obtained connections with unified thread.
