ISO 4126-9:2008涵盖了安全装置的应用和安装，如用于保护压力设备的安全阀、安全阀和爆破片安全装置组合、先导操作安全阀和受控安全泄压系统。ISO 4126-6涵盖了爆破片安全装置的选择、应用和安装。 ISO 4126-9:2008描述了用于保护静压设备的安全装置的应用和安装的规范性要求。ISO 4126-9:2008中包含的信息假设从安全装置排出的流体为单相流。ISO 4126-10提供了特定于两相流条件的指南。 通过具有足够容量的管道在系统中连接在一起的设备，不存在潜在堵塞，且不包含任何可隔离任何部件的阀门，可被视为泄压应用的安全系统。 ISO 4126-9:2008不涉及其他安全装置，例如安全相关的监测、控制和调节装置以及一些国家法规允许的其他限制装置。

ISO 4126-9:2008 covers the application and installations of safety devices such as safety valves, safety valves and bursting disc safety devices in combination, pilot-operated safety valves and controlled safety pressure-relief systems for the protection of pressure equipment. ISO 4126-6 covers the selection, application and installation of bursting disc safety devices. ISO 4126-9:2008 describes the normative requirements for applications and installations of safety devices to protect static pressure equipment. The information contained in ISO 4126-9:2008 assumes single-phase flow of the fluid discharged from the safety device. ISO 4126-10 provides guidance specific to two-phase flow conditions. Equipment connected together in a system by piping of adequate capacity, which is free from potential blockages and does not contain any valve that can isolate any part, can be considered to be a safety system for the application of pressure relief. ISO 4126-9:2008 does not deal with other safety devices, such as safety related monitoring, control and regulation devices and other limiting devices allowed by some national regulations.