According to CCR Title 23 UST regulations, which requirement is NOT applicable for spill containment?

The requirement that is not applicable for spill containment under CCR Title 23 UST regulations is that spill containment must be installed on vent risers. This is because spill containment systems are primarily intended to prevent the spillage of hazardous substances during the filling process of tank systems and are designed for locations directly associated with the storage tank fittings and fill ports. Vent risers, on the other hand, serve a different purpose related to the breathing of the tank and do not typically involve the direct containment of spills resulting from operational activities.

The other mentioned requirements are indeed essential for proper spill containment. The minimum capacity of five gallons ensures that there is adequate volume to handle potential spills. The requirement for containment systems to collect any hazardous substances underscores the importance of environmental safety by ensuring that potential leaks or spills do not contaminate surrounding areas. Lastly, equipping spill containers with a drain valve helps maintain accessibility and functionality by allowing containment systems to be regularly emptied and maintained without the risk of overflow.