What is a requirement to have a fire extinguisher work effectively?

For a fire extinguisher to work effectively, it is crucial that it has not been tampered with. This means it should be in a usable condition, fully charged, and free of any obstructions that could prevent its operation during an emergency. Tampering can include removing the safety pin, discharging the extinguisher, or failing to maintain it according to regulations, all of which would render the extinguisher ineffective when needed.

The other options, while they might relate to fire safety or accessibility, do not directly impact the operational effectiveness of the extinguisher itself. For instance, the color of the extinguisher does not affect its functionality, nor does the location being at the main entrance dictate its readiness. Moreover, while having a fire extinguisher secured is important for safety and preventing misuse, it should be accessible to those who need to use it in case of a fire.