This part of IEC61326 covers all equipment within the scope of IEC61326‑1 , but is limited to systems and equipment for industrial applications within a specified electromagnetic environment and intended to perform safety functions as defined in IEC61508 with SIL 1-3. The electromagnetic environments encompassed by this product family standard are industrial, both indoor and outdoor, and based on the requirements of the process industry, specifically chemical/petrochemical/pharmaceutical manufacturing plants using the mitigation measures given in AnnexC. The difference between the electromagnetic environment covered by this document compared to the general industrial environment (see IEC61326‑3‑1 ) is due to the mitigation measures employed against electromagnetic phenomena leading to a specified electromagnetic environment with test values that have been proven in practice. The environment of industrial application with a specified electromagnetic environment typically includes the following characteristics: industrial area with limited access; limited use of mobile transmitters; dedicated cables for power supply and control, signal or communication lines; separation between power supply and control, signal or communication cables; factory building mostly consisting of metal construction; overvoltage/lightning protection by appropriate measures (for example, metal construction of the building or use of protection devices); pipe heating systems driven by AC main power; no high-voltage substation close to sensitive areas; presence of CISPR 11 Group 2 ISM equipment using ISM frequencies only with low power; competent staff; periodical maintenance of equipment and systems; mounting and installation guidelines for equipment and systems. Equipment and systems considered as “proven-in-use” according to IEC61508 or “prior use” according to IEC61511 are excluded from the scope of this document. Fire alarm systems and security alarm systems intended for protection of buildings are excluded from the scope of this document.