Steam surface condensers may require several different relief devices for safe operation. Atmospheric relief devices are typically utilized for the safe relief of over-pressure on the shell-side (LP steam). This is to protect and prevent steam surface condensers, often including steam turbine exhaust hoods, from exceeding specified design pressures. In addition to shell-side safety devices, relief devices for the tube-side (cooling water), such as water box pressure & vacuum relief, venting and air removal valves, all perform a similar function.
This paper provides a thorough background to all the types of condenser safety relief devices currently available. The latest applicable standards, codes and guidelines for these safety relief devices are reviewed, in conjunction with the current methodology for the correct design and sizing of such devices. Several sample calculations and working examples for the correct sizing of safety devices are provided for reference. The paper includes a review of the relative attributes and considerations for the appropriate selection of each of these types of safety devices, e.g. rupture discs versus atmospheric relief valves for shell-side protection. The paper concludes with a comprehensive review of the latest guidelines for the installation, operation, and maintenance for these safety devices, including guidance on other aspects such as preferred locations, exhaust & vent piping, routine inspection, and testing requirements.