Which of the following details is NOT required on a service tag?

The service tag is a critical component of fire extinguisher maintenance, serving as a record of the service history for the extinguisher. It typically contains important information about the extinguisher, including the date of service, the technician’s details, and compliance with relevant regulations.

When considering the information that is required on a service tag, the owner’s business phone number is not typically mandated by industry regulations. Instead, the focus is on aspects that are directly related to the maintenance and servicing of the fire extinguisher itself and ensuring safety compliance.

The inclusion of specific personal details, like the owner's social security number and the technician's home address, serve different purposes and may be required for documentation or identification in certain contexts. Meanwhile, the extinguisher purchase price is usually relevant for insurance and warranty purposes, but it's not essential information for tracking service history or compliance.

Thus, the reason why the owner’s business phone number is not required on the service tag is due to the focus on technical and compliance-related information that ensures the extinguishers are properly maintained and checked for safety.