What must be ensured during the servicing of a fire extinguisher?

During the servicing of a fire extinguisher, it is crucial to ensure that the correct agent type and weight are used. Each fire extinguisher is specifically designed to combat certain classes of fires, and using an inappropriate agent can be ineffective or even dangerous. For example, using water on an electrical fire could lead to electric shock, while using a foam agent on a flammable liquid fire may not effectively suppress it.

Additionally, the weight of the extinguishing agent is important for the extinguisher to perform as intended. Fire extinguishers are rated based on their capacity to discharge a specified amount of agent over a set period. Using the correct weight guarantees that the extinguisher can deliver the required performance and efficacy during a fire emergency. This adherence to standards is vital for maintaining safety and compliance with fire regulations.

The other options presented are not aligned with proper fire extinguisher servicing practices. Visual inspections are essential to identify any damage or service needs, only new chemicals are not necessarily required (as sometimes refilling with the same type is acceptable), and mixing agents can lead to chemical reactions that are hazardous.