Which component is NOT typically required in vapor recovery systems?

In vapor recovery systems, components are selected based on the specific requirements of the system and the type of fuel being managed. The correct answer indicates that "mandatory on LPG systems" is not typically a requirement for vapor recovery systems.

Vapor recovery systems are predominantly designed to minimize the release of volatile organic compounds into the atmosphere during fuel transfer operations. While some components may be mandatory for motor fuel systems, such as pressure gauges and shut-off valves, LPG systems operate under different considerations.

LPG, which stands for liquefied petroleum gas, has unique properties and may not always necessitate the same level of vapor recovery technology as conventional motor fuels. The requirements for vapor recovery in LPG systems can vary significantly due to the nature of LPG handling, storage, and transfer processes.

Therefore, it's essential to understand that while vapor recovery is an important practice for environmental protection, the mandatory components can differ between different fuel types, leading to the conclusion that the requirement for vapor recovery components in LPG systems is not as universally applied.