What is one of the three mandatory markings on valves used in pressure piping?

One of the three mandatory markings on valves used in pressure piping is the manufacturer's name. This requirement is crucial for several reasons. First, it helps ensure accountability and traceability in case there are issues related to the valve's performance or safety. If a valve fails or there are concerns about its quality, knowing the manufacturer allows for a direct point of contact for investigation and potential recalls.

Additionally, the manufacturer's name contributes to maintaining industry standards and regulations. It often indicates that the valve has been manufactured in compliance with specific codes and guidelines, which are essential for safety in pressure piping systems. Having the manufacturer's name marked on the valve ensures that users can verify that they are using a product that meets the necessary standards for their applications.

The other markings, while important, do not hold the same level of mandatory necessity as the manufacturer's name in terms of regulatory compliance and safety assurance.