What is a requirement for a fire extinguisher's gauge on a school bus?

The requirement for a fire extinguisher's gauge on a school bus is that the needle must be in the green zone. This indicator signifies that the fire extinguisher is fully charged and ready for use. A needle positioned in the green zone indicates that the pressure is at a safe level, ensuring the extinguisher can effectively extinguish fires if the need arises. Having the gauge in the correct zone is crucial for safety, especially in a school bus where the safety and well-being of students and others are the top priorities. Lack of proper functioning fire extinguishers can lead to serious consequences in emergency situations.