What is the design pressure in relation to operating pressure?

The design pressure is the maximum pressure that a vessel, piping system, or equipment is designed to withstand under certain conditions. It is established well above the expected operating pressure to ensure safety and to accommodate potential fluctuations in pressure that may occur during normal operation, maintenance, or upset conditions.

Choosing an answer that indicates the design pressure is somewhat higher than the operating pressure recognizes the need for a safety margin. This margin ensures that the equipment can handle unexpected surges or increases in pressure, which might happen due to equipment malfunction, thermal expansion, or other factors.

By maintaining a design pressure that is higher, it helps prevent failure, leaks, or catastrophic incidents. In engineering practice, this approach is key to ensuring the integrity and reliability of systems that handle gases and liquids under pressure.