Which license type is NOT involved in the installation or servicing of pre-engineered fire extinguisher systems?

The Type R license is focused on the installation and servicing of fire alarm systems rather than fire extinguishing systems. This distinction is important because fire alarms and pre-engineered fire extinguisher systems fall under different regulatory and licensing requirements.

The other license types, such as Type A, Type PL, and Type B, are relevant to various aspects of fire protection, including the installation and maintenance of fire extinguishers and related systems. Type A typically pertains to a more general category of fire protection systems, while Type PL might involve specific licensing related to portable fire protection equipment. Type B is often associated with systems beyond just alarms, which may include the types of systems that utilize extinguishers.

Understanding the roles and regulations associated with different licenses is crucial for ensuring compliance and effective fire safety management. In this context, the Type R license is not applicable to pre-engineered fire extinguisher systems, which is why it stands out as the correct choice.