Canadian Entry To Practice (CETP) Practice Test

The first stage regulator is designed to control the pressure of gas directly at the tank before it enters further stages of regulation for distribution and use. It's typically set to a pressure that is suitable for the specific gas application, ensuring that it operates within safe and efficient parameters.

In this context, the measurement given in inches of water column (WC) indicates a low-pressure application, which is common for systems that require a stable and lower pressure supply. The choice of 11" WC aligns with standard practices for first stage regulators in many common gas applications, serving as a safe entry pressure level that is appropriate before the gas is further reduced in pressure by subsequent regulators.

This measurement indicates that the first stage regulator effectively minimizes the risk of pressure surges that may occur as gas moves from the high-pressure tank into the lower-pressure lines or appliances, while the other options, which use PSI, do not conform to the typical pressure levels for this stage in common applications. Thus, the choice of 11" WC is correct for understanding the role of the first stage regulator.