本标准的目的是帮助定义在使用蒸汽进行传热的系统内，正确确定和选择2型二次压力排水器（SPD）所需的信息。了解该标准后，可将其应用于此类系统，以提供有效且适当的冷凝水排放。这是蒸汽使用设备在安全环境中保持一致传热的必要功能。

The purpose of this standard is to help define the information required for proper sizing and selection of Type 2 Secondary Pressure Drainers (SPD) within systems utilizing steam for heat transfer. With an understanding of this criteria, it can be applied to these types of systems to provide effective and proper condensate drainage. This is a necessary function of steam-using equipment to maintain consistent heat transfer in a safe environment.