In the past it was very common to find - on microwave ovens or other types of ovens - a warning on the lid that indicated "Danger: hot surface". Over the years this type of warning has almost disappeared, in relation to one restriction contained in the harmonized standard of the European Commission, which marked the update of the previous regulatory framework.
Danger warnings and exceptions to temperature limits
To motivate them danger warnings on the oven lids it was precisely the norm dedicated to them. In EN 60335-2-9:2003 + A2:2006 + A1:2004 + A2:2006 + A12:2007 + A13:2010, in fact, there is a note that it would indicate a possible exception to the maximum temperatures, applicable in some cases and with - precisely - the necessary affixing of the hot surface warning.
Examining the note b of Table Z101 (added with A13:2010) we learn that - if the temperature standards cannot be respected due to construction or dimensional limitations of the appliance - the maximum temperature increase could be double the values in the table. In that specific case, therefore, the hot surface warning should be applied to the appliance.
A basic aspect to underline is that this significant change in temperature limits would be permitted only in the presence of a real and objective construction or dimensional limitation that prevented the original limits from being respected.
The sentence of the note referred to perfectly explains theexceptional nature of the case. Here is the full text: “When, due to the construction or dimensional limitations of the appliance, the required values cannot be met, the maximum temperature rise shall not be higher than twice the values indicated. In such cases, a warning shall be marked on the relevant surface of the appliance“.
The restriction of the European Commission
In the list of harmonized standards published in the European Journal, where this amendment is implemented, there is a section that excludes the note indicated above, redefining the standards for product safety.
The full text is reported below: “The application of the following parts of standard EN 60335-2-9:2003, as last amended by A13:2010, does not confer a presumption of conformity to the safety objectives laid down in point 1(c) of Annex I to Directive 2014/35/EU, in conjunction with point 2(b) of that Annex:
- footnote b of Table Z101 in Section 11,
- the parts of Section 7.1 which refer to footnote b of Table Z101,
- the parts of Section 11.Z10x which refer to ventilation openings.”
The restriction in question was produced in 2017 and has therefore been in force ever since it is not possible to use note b of Table Z101 by increasing the temperature limits, not even reporting the danger warning referred to in Table Z101.
As is known, harmonized standards are written on behalf of the European Commission And a ruling by the latter has priority.
To date, in laboratory practice and in product safety analysis that we usually carry out, we happen to examine products that - although correctly in line with current standards - carry the danger warning, although this is not necessary.
These are not backlog products, but case studies that stimulate reflection on the warnings between producer and consumer. The warning of “Danger. hot surface” is, clearly, a practice not prohibited, but really inadvisable since unnecessary alerts distract from the important ones, on which it would be correct to focus attention.
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