/community-hubs/valves-actuators-regulators/b/vcp-weblog/posts/airset-regulators-understanding-a-critical-but-often-overlooked-link-in-safety-systemsEngineers who design safety systems are always mindful of a few basic truths: Anything can fail, so there should always be a backup. And sometimes, backups need backups. Looking at how this concept applies to pneumatically operated emergency shutdownen-USTelligent Community 13