Chapter 12 - Floating of Steam Generator Safety Valves

Abstract

To meet statutory requirements of a boiler inspectorate or regulatory authority, spring-loaded safety valves are installed on boiler drum/steam separator outlet, main steam, cold reheat, and hot reheat pipe lines. Safety valves ensure continued safe operation of steam generators against overpressure. Total relieving capacity of all safety valves is equal to or more than BMCR steam generating capacity. Electrically assisted relief valves are installed on main steam and hot reheat pipe lines. Each safety valve is provided with an escape pipe, drain pan, and silencer. Setting of safety valves is adjusted before a steam generator is started in normal operation. Either a “full set pressure valve actuation” (most reliable technique) or “lift-assist device” (normal operating pressure method) is used for floating of safety valves.