What is the maximum pressure drop through the vapor recovery system at 60 cubic feet per hour as determined by TP-201.4?

• A. 0.75 inches WC
• B. 0.5 inches WC
• C. 0.32 inches WC
• D. 0.55 inches WC

Answer: (B)

The maximum pressure drop through the vapor recovery system at a flow rate of 60 cubic feet per hour, as determined by the TP-201.4 method, is established to ensure efficient operation of the vapor recovery systems while minimizing the likelihood of vapor release into the atmosphere. A pressure drop of 0.5 inches of water column (WC) is the specified limit that reflects an optimal balance between maintaining adequate vapor recovery and ensuring that the system operates without excessive resistance that could hinder performance.

This drop in pressure is crucial because it influences the system's effectiveness in capturing vapors from the storage tanks during product transfers. If the pressure drop is too high, it can lead to increased operational difficulties and potential failures in vapor recovery functionality.

The method TP-201.4 provides the necessary guidelines and benchmarks for assessing vapor recovery systems, establishing the 0.5 inches WC figure as a standard for performance measurement in systems working at that specified flow rate. This means that systems should ideally maintain pressure drops at or below 0.5 inches WC to remain compliant and efficient in their vapor recovery goals.