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Advice on ATEX glanding.

Mspark

Good evening and thanks for looking.

I've had a look at a brand new piece of equipment that needs to be maintained in the coming months. The threads on Exd glands into threaded housings in zone 2 IIC have been coated with copper ease, I understand a non conductive lubricant can be used on threads but I would expect the copper ease to be conductive. Am I right to be concerned. Thanks

Parents
  • 0

    Was the copper grease applied by the manufacturer / installer?

    What is your thinking behind the need for a non-conductive grease?

    You wouldn't be confusing this with the need for a non-setting grease to be used on Ex d enclosure flanges, where required?

    - Ross

  • 0 in reply to Ross C

    As you have mentioned that the piece of equipment is certified for gas subdivision IIC, is there any risk of acetylene being present?

    - Ross

Reply Children
  • 0 in reply to Ross C

    No acetylene, the hazardous area is compressed hydrogen.

  • +1 in reply to Mspark

    IEC 60079-1 (the constructional standard for Ex d enclosures) gives effectively the same requriements for properties of grease for use on Ex d flanges and other flamepaths as those given in the extract by  from IEC 60079-14 with the addition of:

    '. . . does not contain an evaporating solvent . . .'

    There doesn't appear to be a explicit requirement in either standard relating to the conductivity or non-conductivity of grease, other than the requirement in the IEC 60079-14 extract that:

    ' . . . any earthing across the flamepath shall be maintained.'

    However, I am slightly curious regarding the use of copper grease on equipment for gas subdivision IIC due to the potential for the formation of copper acetylide in contact with acetylene.

    - Ross 

  • 0 in reply to Ross C

    I didn't know what 'copper acetylide' was, or did, so I asked the web, which said

    "It's a reddish-brown, explosive powder and is also known as cuprous acetylide or copper carbide."

    I now see why it might be important... Scream

  • 0 in reply to Philip Oakley

    Yes - copper or silver in contact with acetylene have the potential to form explosive acetylides! 

    On a related note, there are also restrictions on the use of aluminium, magnesium, titanium and zirconium in Ex equipment, but for a different reason - the risk of sparking as a result of impact or friction.

    - Ross 

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