Answer:
The nominal inches of water column pressure that must be maintained during a timed pressure drop test is typically specified at 10 inches.
Step-by-step explanation:
In pressure drop testing, maintaining a nominal pressure of 10 inches of water column is crucial. This pressure level is considered standard for evaluating the performance and integrity of various systems, such as HVAC ductwork or gas piping. It ensures that the components can withstand the expected operating conditions and potential variations in pressure.
The 10 inches of water column is chosen as a benchmark because it represents a realistic and common pressure scenario in many applications. This standardized approach facilitates consistent testing across different industries and applications.