What is the primary purpose of a double block and bleed system?

The primary purpose of a double block and bleed system is to ensure complete isolation of a section within a piping system. This design employs two isolation valves situated on either side of a bleed valve. When both isolation valves are closed, the bleed valve allows for the safe venting of any trapped pressure or fluid. This system is crucial in preventing leaks and providing safety during maintenance or inspections, making it essential in preventing hazardous situations in process environments.

In situations where proper isolation of equipment or sections of piping is necessary—for example, during maintenance on hazardous materials—this system provides an extra layer of security. It guarantees that no fluid can inadvertently escape, thus safeguarding personnel and equipment from potential dangers associated with fluid leaks.