Red Seal Instrumentation and Control Technician Practice Exam

What is the primary function of an isolation valve in a piping system?

1. To regulate the pressure in the system

2. To prevent flow in a section of piping for maintenance or safety purposes

3. To increase the temperature of the fluid

4. To measure the flow rate

The correct answer is: To prevent flow in a section of piping for maintenance or safety purposes

The primary function of an isolation valve in a piping system is to prevent flow in a section of piping for maintenance or safety purposes. Isolation valves are critical components in many piping systems, enabling technicians to safely perform maintenance or repairs without having to drain the entire system or disrupt the operation of other parts. By allowing specific sections to be isolated, these valves enhance safety and efficiency in maintenance activities. While regulating pressure is essential in some context, it is not the primary role of an isolation valve, as pressure regulation typically involves different types of devices specifically designed for that purpose, such as pressure relief valves or regulators. Similarly, increasing the temperature of the fluid falls outside the scope of isolation valves, which do not have mechanisms for thermal control. Measuring the flow rate is another distinct function generally carried out by flow meters, rather than isolation valves, which are designed solely to control flow by opening or closing.