Carbon Dioxide (CO2) F.F. System supplied by EUSEBI IMPIANTI

Extinguisher

Carbon dioxide is a compound made up of carbon and oxygen, its chemical formula being CO₂.

At atmospheric pressures and ambient temperatures, it is a colourless, tasteless gas with a slight odour. It does not damage material it comes into contact with, does not leave any residue and has very good dielectric characteristics.

Depending upon the temperature and pressure it is put through, it can become solid, liquid or gaseous.

It is possible for it to be in the three phases contemporarily at a temperature of -5°C and as a relative pressure of 4.28 kg/cm² (condition known as the triple point).

At a temperature lower than the triple point, the carbon dioxide is solid or gaseous.

The solid carbon dioxide, at sublimation atmospheric pressures, passes directly from a solid state to a gaseous state.

At temperatures higher than the triple point, but lower than 31°C, (critical temperature) it is only in the gaseous state.

One kilo of CO₂, in the liquid state and at a temperature of 20°C, develops approximately 510 litres of gas when expelled at the atmospheric pressure and ambient temperatures.

The physical characteristics of carbon dioxide are:

Chemical formula................................................................................................. CO₂

Molecule weight................................................................................................... 44

Triple point........................................................................................................... -56°C 4.28 bar rel.

Sublimation temperature at atmospheric pressure............................................. 78.9°C

Critical temperature............................................................................................. 31°C

Critical pressure................................................................................................... 73.96 bar rel.

Sublimation heat at -78.9°C................................................................................ 136,89 cal/kg

Specific weight in the gaseous phase at 0°C and at atmospheric pressure........ 1.977 kg/m³

Used for inerting purposes CO2, like other inert gases, drops down oxygen concentration avoiding the event of combustion with high velocity (explosion). In this installation, minimum quantity to be discharged in protected areas are evaluated by CO detectors, located into silos.

The extinguishing action of carbon dioxide happens by suffocating the fire, diluting the percentage of oxygen contained in the air and by the cooling action provoked by the rapid expansion of gas.

High pressure F.F. System

The Carbon Dioxide (CO₂) fire fighting system consists of CO₂ cylinders (out of supply), installed on racks, near the rooms/machines to be protected, remotely or manually actuated, which discharge the CO₂ inside the rooms and/or around the machines by discharge cones.

The extinguishing agent charge in the cylinder is carried out in tropical charge type corresponding to 0.67 kg of CO₂ per litre capacity of cylinder, for ambient temperature over than 45°C.

Functional Description

The CO₂ F.F. System assures fire extinguishment by means the flooding of the protected zone and is designed and sized for flowing the protected room with the required quantity of CO₂.

The CO₂ rapid discharge carried out by means no. 2 CO₂ cylinders occurs by three methods:

1. Electric actuation, by remote control, through junction boxes installed on CO₂ racks; in this modality, a +24V supply, from remote actuates both solenoid valves on pilot cylinders: actuation of solenoid valve determines the CO₂ pilot cylinder discharge in distribution manifolds, and a part of it fills the interconnection circuit actuates the valve of the relevant piloted cylinders, thus determining their discharge in the protected room.
2. Electric actuation, by the emergency P.B. local pushbutton on the external side of protected rooms; this equipment stars the previous described actuation method.
3. Manual actuation, by operating the pull box installed on racks connected to Electric/manual actuator of both pilot cylinders; in this modality, by opening the discharging valve of the pilot cylinder the CO₂ pressurizes the relevant manifold thus actuating the corresponding piloted cylinders. The manual actuation shall be used only for emergency when electric actuation systems are fault.

Signallings of F.F. System systems to remote consist of:

System in operation alarm signal, supplied by PSH pressure switch, on the rapid discharge distribution manifold. After operation it is necessary to manually reset the pressure switch.

During CO₂ discharge, in addition, two pressure release devices, actuated by the CO₂ pressure inside the distribution piping, closes the air vent panels.

Enclosed in EUSEBI IMPIANTI supply, in addition, a low frequency alarm siren, a red alarm flashing lamp, to signal the system in operation.