Hot Surface Warning

[homoly]

Hi,

I would like to ask what is the threshold surface temperature of electrical devices from which the application of "HOT SURFACE" warning sticker is mandatory and which standard(s) could be applied ?

 

[ScottyUK]

You might see if you can get a look at: BS EN 563 Safety of machinery – Temperatures of touchable surfaces – Ergonomics data to establish temperature limit values for hot surfaces

It is likely defined in a standard applicable to wherever you are - without that information it's difficult to help.


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If we learn from our mistakes I'm getting a great education!

 

[homoly]

Thanks Scotty for your entry. I would rather be interested in PDU and switchgear's cabinets used in the power distribution like in machinery, but I will try to have a look on machinery standard.

Basically, I would like to know when is the usage of the following sign type mandatory :

http://www.speedysigns.com/decals/WARNING_Hot_Surface_Do_Not_Touch.asp

 

[matthewm1965]

It varies depending on size, shape and surface texture of the item in question.
As a general rule of thumb, we put the warning label on any equipment that may reach above above 60 degC. VFD heatsinks for instance.
Matt

 

[homoly]

Matthewm1965, thank you for the hint.

 

[burnt2x]

I think the maximum allowable surface temperature that will produce burns to skin when in contact with said hot surface is 43^o Centigrade. Most hospitals and nursing care institutions require putting up warning labels "WARNING, VERY HOT".

Suggest you try NIMA website for details -National Insulation Manufacturers Association.

Also, temperatures over 80^o Centigrade can cause 2nd degree burns (definition of arcflash protection boundary to limit burns to a curable 2nd degree burn, temp >80^o)
Hope this helps

 

[ScottyUK]

The 43[°]C limit is for vulnerable or infirm persons who may become 'permanently' in contact with the hot surface through inability to remove themselves from it. I am pretty sure the limits are higher where those exposed to the hazard are not reasonably expected to be infirm or vulnerable.


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If we learn from our mistakes I'm getting a great education!

 

[homoly]

Thank you the 43degC information is also useful for me.

I have found at the OSHA discussion

http://www.eng-tips.com/viewthread.cfm?qid=79451

that the suggested limit should be around 140F ( 60 C ).