This part of ISO 21904 defines the general requirements for ventilation equipment used to capture and separate fumes generated by welding and allied processes e.g. arc welding and thermal cutting. It applies to the design and manufacture of parts of the equipment including hoods for welding, ducting, filter units, air movers, systems that inform of unsafe operation and workplace practices to ensure safe working with regard to exposure. Significant hazards are listed in Clause 4. It does not cover electrical, mechanical and pneumatic hazards. This part of ISO 21904 is applicable to the following: local exhaust ventilation systems (LEV) excluding draught tables; mobile and stationary equipment; separation equipment used for welding and allied processes; This part of ISO 21904 is not applicable to the following: general ventilation, air make up or air movement systems; air conditioning systems; grinding dust. This part of ISO 21904 also specifies the test data to be marked on the capture devices. This part of ISO 21904 applies to systems designed and manufactured after its publication.