What is the minimum acceptable weight of a '100 pound' cylinder in a CO2 fire extinguishing system before it needs recharging?

In the context of CO2 fire extinguishing systems, the weight of a cylinder is critical for determining whether it is full and ready for use. A '100 pound' CO2 cylinder is designated to contain 100 pounds of carbon dioxide when fully charged. Fire safety regulations stipulate that a cylinder that has lost a significant amount of its contents, typically around 20%, should be recharged to ensure it remains effective.

To find the minimum acceptable weight before recharging is necessary, we can calculate 80% of the total weight capacity of the cylinder. Since it is a '100 pound' cylinder, this means it should maintain at least 80 pounds (which is 80% of 100 pounds) of CO2. Therefore, when the cylinder falls below this weight, it must be recharged.

Now, if we look at the presented options, the 220 pounds choice represents a misunderstanding of the ratio applied to a '100 pound' cylinder. The correct minimum weight for recharging is not as high as the other answer choices, such as 250 pounds, which considerably exceeds the capacity of the cylinder.

Thus, the answer of 220 pounds does not apply because it's too high compared to the actual designed capacity of the cylinder.