Final answer:
The minimum temperature in degrees Fahrenheit at which combustible liquids have a flash point is below 73 °F, corresponding to Category 4 liquids. Understanding flash points is critical for proper storage and handling to prevent fires.
Step-by-step explanation:
The question pertains to the flash point of combustible liquids, which is the minimum temperature at which a liquid forms a vapor above its surface in sufficient concentration that it can ignite when exposed to an ignition source.
According to the given information, combustible liquids have various classifications with respect to their flash points:
- Category 4: Flash point below 73 °F.
- Category 3: Flash point below 100 °F.
- Category 2: Flash point above 100 °F but not exceeding 200 °F.
- Category 1: Flash point above 200 °F.
- Category 0: Substance will not burn.
The minimum temperature in degrees Fahrenheit at which combustible liquids have a flash point is therefore below 73 °F (Category 4).
Descriptions of waste liquids indicate that common waste liquids with a flash point occur below 60 °C (equivalent to 140 °F), including used solvents and waste oils.