DIN EN 50402-2009 易燃或有毒气体或蒸气或氧气的探测和测量用电气设备.混合气体探测系统的功能安全要求
Electrical apparatus for the detection and measurement of combustible or toxic gases or vapours or of oxygen - Requirements on the functional safety of fixed gas detection systems; German version EN 50402:2005 + A1:2008