Final answer:
CO2 extinguishing systems rely on carbon dioxide, which can be in liquid form below its critical temperature of 31 °C. Above this temperature, CO2 cannot be liquefied, influencing the system's performance.
Step-by-step explanation:
The question pertains to CO2 extinguishing systems and the behavior of CO2 under different temperatures. On a cool day, at 18 °C, which is below the critical temperature of carbon dioxide (304 K or 31 °C), liquid CO2 is present inside the fire extinguisher. In contrast, on a hot summer day with temperatures beyond the critical temperature of CO2, specifically at 35 °C, the contents of the same extinguisher will not include liquid CO2 because the gas cannot be liquefied regardless of the pressure applied.
Therefore, the extinguishing system's ability to displace oxygen and quench fires is attributed to carbon dioxide in its gaseous state, which is heavier than air.
There are two types of CO2 extinguishing systems: total flooding systems and local application systems.
Total flooding systems involve flooding a closed space, such as a computer room, with carbon dioxide. The carbon dioxide displaces the oxygen, suffocating the fire.
Local application systems, on the other hand, release carbon dioxide directly onto specific areas or objects to extinguish the fire.