Final answer:
Special extinguishing systems designed to protect gasoline storage tanks commonly utilize fluorinated foam, which can effectively spread over and extinguish fires involving flammable liquids. Traditional methods such as dry-cleaning solvents are no longer recommended. These systems must be environmentally safe and account for factors like the thermal expansion of gasoline and storage materials.
Step-by-step explanation:
The type of special extinguishing system used to protect areas such as gasoline storage tanks is commonly based on the use of foam. This foam is specifically designed to suppress the intense and rapid spread of fire that can occur when flammable liquids like gasoline are ignited. A fluorinated solution is an example of such a foam, which can spread across the burning surface and extinguish a fire effectively.
Other fire suppression methods previously used included dry-cleaning solvent and certain types of fire extinguishers, although these are no longer recommended. Over the years, advances in fire extinguishing systems have led to the development of foaming agents that are less harmful to the environment and more effective at smothering fires in high-risk areas such as gas stations, storage tanks, and processing plants.
Protecting the integrity of storage tanks is critical, as seen in Example B.4.2, where the safety of gas stored at high pressure is a concern. This example also emphasizes the importance of understanding the thermal expansion properties of both the gasoline and the containers it is stored in. The design of containment systems must incorporate a significant safety factor to accommodate any increase in pressure due to heat exposure.
Environmental protection is another concern where fire suppression systems that interact with gasoline must be considered. Substances like methyl t-butyl ether (MTBE) were used as octane enhancers in gasoline but have been phased out due to groundwater contamination risks. Nowadays, ethanol and other environmentally friendly alternatives are used instead.