This document specifies requirements for the electromagnetic compatibility (EMC) for electrical apparatus for the detection and measurement of combustible gases, toxic gases or oxygen which are subject to the performance standards for gas detection apparatus, for example EN 45544 (all parts), EN 50104, EN 50194 (all parts), EN 50291 (all parts), EN 50379 (all parts), EN 50543, EN 50545 1, EN 60079 29 1 or EN 60079 29 4. NOTE For the purpose of this standard, the word ‘toxic’ covers ‘very toxic’, ‘toxic’, ‘harmful’, ‘corrosive‘, ‘irritating‘, ‘sensitizing‘, ‘carcinogenic‘, ‘mutagenic‘ and ‘teratogenic‘. This document applies to apparatus intended for use in residential, commercial and light-industrial environments as well as to apparatus intended for use in industrial environments, and includes AC-, DC- or battery powered apparatus. This document is also applicable to apparatus which is intended for use in hazardous areas which could contain explosive or potentially explosive atmospheres. It covers only normal operation and does not cover safety requirements related to EMC phenomena. This document is a product standard which is based on the product family standard EN 61326 1. prEN 50270:2019 takes precedence over the product family standard and over generic standards. This document applies to electrical apparatus for the detection and measurement of combustible gases, toxic gases or oxygen that include functions specified by the manufacturer as being safety functions and can include functions specified as not being safety functions. All performance standards for the detection and measurement of combustible gases, toxic gases or oxygen include the minimum requirements for functional safety specified in EN 50271. There are also gas detectors and gas detection systems which are intended to be used with safety integrity levels SIL 1 to SIL 3 according to EN 50402 and EN 61508 (all parts). For functional safety in industrial applications, this document has taken into account those aspects of EN 61326 3 2 relating to the measuring and warning function of the apparatus defined as safety function. This standard specifies requirements for immunity tests in relation to continuous and transient, conducted and radiated disturbances, including electrostatic discharges, and also for emission tests. The test requirements are specified for each port considered. Apparatus falling within the scope of this document are classified as follows by the following types. — Type 1: apparatus intended for use in residential, commercial and light-industrial environments, as described in EN 61000 6 1 and EN 61000 6 3. — Type 2: apparatus intended for use in industrial environments, as described in EN 61000 6 2 and EN 61000 6 4. Type 1 apparatus for which the manufacturer claims a safety integrity level should be considered as type 2 apparatus with regard to immunity requirements. This document does not apply to any of the following: — apparatus intended for the detection of dusts or mists in air; — scientific or laboratory based apparatus used only for analysis or measurement; — apparatus used exclusively for process measurement purposes; — apparatus for medical purposes; — apparatus used for breath alcohol measurement — apparatus intended for the direct measurement of automotive exhaust gases.