CEN/TC 186/WG 2 - Combustion and fuel handling systems - Safety requirements

This document specifies the safety requirements for combustion and fuel handling systems that are part of industrial furnaces and associated processing equipment (TPE), including single and multiple burner systems in thermoprocessing equipment and machines.
NOTE            The general safety requirements common to TPE are provided in ISO 13577-1:2016. ISO 13577-1:2016, Annex B also includes a list of processes for which industrial furnaces and heating systems covered by the ISO 13577 series are used.
This document deals with significant hazards, hazardous situations and events relevant to combustion and fuel handling systems as listed in Annex A, when used as intended and under the conditions for use as described in the instruction handbook.
This document covers:
—     fuel pipework downstream of and including the manual isolating valve;
—     combustion air supply (including oxygen and oxygen enriched combustion air) and flue gas system;
—     burner(s), burner system and ignition device;
—     functional requirements for safety related control system.
This document applies to any oxidation of gaseous and liquid fuels with air or other gases containing free oxygen to release thermal energy in TPE. Annex B includes examples of gaseous and liquid fuels.
For thermal or catalytic post combustion and waste incineration, this document applies only to auxiliary burners designed to start-up and/or support the process.
The pressure hazard of the piping and components covered by this document is within the maximum pressure/size relationship of category I as specified in Annex C.
This document also gives the necessary requirements regarding information for use.
This document does not cover hazards from heating generated by electricity.
This document does not deal with the hazards created by the release of flammable substances from the products processed in the TPE.
This document is not applicable to combustion and fuel handling systems:
—     of gas welding and allied processes;
—     up-stream of the TPE manual isolating valve.
This document is not applicable to industrial furnaces and associated processing equipment (TPE), including single and multiple burner systems in thermoprocessing equipment and machines manufactured before the date of its publication.
This document is not applicable to blast furnaces, converters (in steel plants), boilers, fired heaters (including reformer furnaces) in the petrochemical and chemical industries.
This document is not applicable to electrical cabling and power cabling upstream of the TPE control panel/protective system.

This part of EN 746 specifies the safety requirements for combustion and fuel handling systems that are part of industrial furnaces and associated processing equipment (TPE).
NOTE   The general safety requirements common to TPE are provided in prEN 746 1:2020 (See introduction).
This part of EN 746 deals with significant hazards, hazardous situations and events relevant to combustion and fuel handling systems as listed in Annex A, when used as intended and under the conditions foreseen by the manufacturer.
This part of EN 746 covers:
-   fuel pipework downstream of and including the manual isolating valve;
-   combustion air supply (including oxygen and oxygen enriched combustion air) and flue gas system;
-   burner(s), burner system and ignition device;
-   functional requirements for safety related control system.
This part of EN 746 applies to any oxidation with air or other gases containing free oxygen of gaseous and liquid fuels or any combustion of them to release thermal energy in TPE.
For thermal or catalytic post combustion and waste incineration, this part of EN 746 applies only to auxiliary burners designed to start-up and/or support the process.
The pressure hazard of the piping and components covered by this part of EN 746 is within the maximum pressure/size relationship of category I as described in normative Annex E.
This part of EN 746 also gives the necessary requirements regarding information for use.
This part of EN 746 does not cover hazards from heating generated by electricity.
This part of EN 746 does not deal with the hazards created by the release of flammable substances from the products processed in the TPE.
This part of EN 746 is not applicable to combustion and fuel handling systems:
-   of gas welding and allied processes;
-   up-stream of the TPE manual isolating valve.
This part of EN 746 is not applicable to electrical cabling and power cabling upstream of the TPE control panel/protective system.

This part of EN 746 together with EN 746-1 specifies safety requirements for single and multiple burners that are part of Industrial Thermoprocessing Equipment. (In this standard referred to as IThE).
This document deals with significant hazards, hazardous situations and events relevant to combustion and fuel handling systems that are part of IThE as listed in Clause 4, when used as intended and under the conditions foreseen by the manufacturer.
This European Standard covers:
- fuel pipework downstream of and including the manual isolating valve;
- burner(s), burner system and ignition device;
- safety related control system (protective system).
This European Standard applies to any oxidation with air or other gases containing free oxygen of gaseous, liquid and solid fuels or any combustion of them to release thermal energy.
For thermal or catalytic post combustion and waste incineration, this European Standard applies only to auxiliary burners designed to start-up and/or support the process.
The pressure hazard of the piping and components covered by this standard is within the maximum pressure/size relationship of category I as described in normative Annex D.
This European Standard also gives the necessary requirements for the information for use.
This European Standard does not cover hazards from heating generated by electricity.
This European Standard does not deal with the hazards created by the release of flammable substances from the products processed in the IThE.
NOTE EN 1539, Dryers and ovens, in which flammable substances are released — Safety requirements
This European Standard is not applicable to combustion and fuel handling systems
- of welding and soldering machines;
- up-stream of the IThE manual isolating valve.
This European Standard is not applicable to electricity cabling and power cabling upstream of the IThE control panel/protective system.
Noise can be a significant hazard for combustion and fuel handling systems.

This Part of EN 746 applies to all combustion and fuel handling equipment used in industrial thermoprocessing equipment which meets the definition for machinery given in 3.1 of EN 292-1:1991, referred to hereafter as "equipment", e.g. furnaces, kilns, ovens, heating systems such as salt baths and melting tanks, and equipment such as integrated burners and torches used in casting machines, ladle heating etc.  It applies to the handling of fuel immediately adjacent to the equipment but downstream of and including the main plant manually operated fuel shut off valve. It specifies the list of hazards, the safety requirements and associated measures as well as the user instructions relating to fuel handling and combustion equipment.  It applies to all forms of gaseous, liquid and solid fuel and any combinations of them in combustion with air or other gas containing free oxygen.  This Part of EN 746 also applies to gas torches, work station burners, working flame burners and other burners not integral with the plant, even though they are not covered by the mandate.  This Part of EN 746 specifies the requirements to be met by the manufacturer to ensure the safety of persons and property during commissioning, start-up, operation, shut-down and maintenance, as well as in the event of foreseeable faults or malfunctions. It specifies the safety requirements at stages in the life of the equipment, and its design, ordering, construction and use.   The hazards covered by this Part of EN 746 are listed in clause 4.  This Part of EN 746 applies to equipment which is placed on the market after the date of issue of this standard.  This Part of EN 746 does not apply to but may be used as reference for:    - gas torches for welding, flame cutting and related processes; - boiler installations; - environmental space heating of any kind; - the storage of fuel; - industrial food processing.