Under what condition can portable extinguishers be serviced without a label of approval?

The correct answer is based on the regulatory framework established by the Coast Guard, which allows for specific conditions under which servicing can be performed without an approval label. The Coast Guard has its own set of standards and requirements that govern the servicing of extinguishers on vessels. When firefighting equipment is maintained in accordance with these requirements, it may not necessitate the display of an approval label, contingent upon compliance with the applicable regulations.

This highlights the importance of adhering to federal standards and guidelines concerning fire safety equipment, particularly in maritime settings. It's essential that service personnel follow the Coast Guard's established parameters for maintenance to ensure safety and functionality.

Other options present conditions that do not align with the established regulations for servicing extinguishers. For instance, simply having an extinguisher over 10 years old does not automatically exempt it from needing a label; rather, the age could necessitate specific inspections. Written consent from the owner does not pertain to approval standards for extinguishers nor ensure that they meet safety requirements. The presence of certified personnel is important for quality assurance, but their presence alone does not negate the need for a label of approval according to the Coast Guard's stipulations.