Like the Industrial Heating Equipment Association (IHEA) in the United States, Europe has a trade association. The 33-year-old Committee of Industrial Furnace and Heating Equipment Associations (CECOF), headquartered in Frankfurt, consists of European associations that are themselves made up of manufacturers. In the mid-1990s, after a multi-year effort, the group released the final draft of what became EN746 Part 2, which provides standards for burners and fuel-handling equipment for manufacturers. Before EN746, there had been no European standard on ovens, furnaces and other combustion and fuel-handling equipment. In Europe, EN746 is called a C standard, which means it contains requirements for a particular group of products.

In February of 1997, the document was ratified by the European Union’s member states and published in the official journal of the European communities. Then, in 2002, just five years later, the word came for an update of Part 2.

There were good reasons for that update.

• There were newer technologies that were not available when CECOF was preparing the original text. A few examples: PLC control was used very often and, of course, the safety conditions of that usage had to be codified; oxy-firing had become a common way of reducing NOX in the flue products; and specifics for this mode of combustion also had to be outlined.
  
• New directives were released or updated, and they had to be taken into account, such as the pressure equipment directive and the explosive atmosphere directive.
  
• Some of the existing text was subject to misinterpretation. One typical case was the issue of the number of safety shutoff valves. The 1997 standard required two of them to shut off the fuel supply in case of a failure lockout. For a single burner, this was fairly straightforward. But for multiple burners, the text was ambiguous because it allowed the manifold valve to be one of the two, with the second being the local valve. This ambiguity lead to companies using either three valves (two in the fuel manifold and one at each individual burner) or four valves (two in the manifold and two at each burner). For installations with 100 burners or more, this represented an enormous difference of cost.

So, where are we now?

It is a bit too soon to detail all the differences because the revised text still has to go through some cosmetic modifications by other groups. What I can tell is that the new text is substantially different from the previous EN746-2 and should provide better answers to all European oven and furnace manufacturers when they are doing risk assessment prior to certifying compliance with the Machinery Directive and using the CE marking on their industrial thermal processing equipment.

What is the procedure from now forward?

The EN746-2 document should be released this summer as a provisional standard (prEN746-2:2005) by CEN, the European Standardization Committee. It then will go to a public inquiry for six months. Then, based on the responses of the member states of the European Union (there are now 25, plus the members of EFTA zone), the document will be finalized and sent for the final vote. As soon as the prEN746 document is available, it becomes public. It then can be used by combustion equipment manufacturers and designers for their assessment. During a transition period of 12 months, both the old text (EN746-2:1997) and the new text (prEN746-2:2005 and EN746-2:2006) will be valid. After that period, only the new text will be in effect. PH