If the plant is configured in a Parallel arrangement, the HP Bypass Valve will direct the outlet steam flow to the condenser. If the plant is configured as a Cascading system (the most common in today’s plants) the steam will be directed to the Cold Reheat section of the boiler or steam generator. Regardless, these valves will warrant the highest pressure ratings which may go as high as ASME 4500. The valves are commonly manufactured from forged materials which allow for higher strength and ductility when compared to the equivalent cast material. The additional strength of the forged materials also provide greater manufacturing flexibility which allows for optimised contours and shapes that can result in thinner wall sections being applied to the valve body design. This helps in reducing the effect of thermal gradient stress across the body caused by the rapid and sudden opening of the valve during a turbine trip sequence. The Hot Reheat (HRH) bypass valves (sometimes referred to as Intermediate or Medium Pressure) are used to bypass steam to the condenser regardless of whether the bypass system is configured as parallel or cascading. The required flow coefficient, Cv, for these valves is often the largest in the system due to the combination of lower steam pressures and higher temperatures emanating from the re-heater. They are used to convert the HRH steam to conditions more acceptable for admission into the condenser. As a result of the high steam temperatures entering these valves, they normally require a significant amount of desuperheating flow to reduce the outlet enthalpy to acceptable condenser inlet conditions.