Brine attack on LSZH optical fibre

[ScottyUK]

I was copied in an email exchange regarding possible attack on the sheath of low smoke / zero halogen optical fibre (and presumably other LSZH cables too). This is something I've not heard of before and was wondering if it is a problem familiar to others. Any references or case studies would be very welcome, as would any assist on a brine-resistant LSZH optical cable.


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

 

[7anoter4]

I don't know a salt mist test requirement for any cable. There are requirements for salt mist test for connectors see [for instance]:

http://www.hirose.co.jp/cataloge_hp/e74902032.pdf

The optical cable components [silica or POF or jacket-PE or PUR-] are not sensible to salt -as far as I know-and salt water penetration is usually blocked.
But there are other components sensible to salt[brine] as aluminum foil or corrugated steel armor. The filling Petroleum Jelly may be sometime sensible to concentrated brine- as I heard. Also aramid inner sheath is sensible to salt.I'm not sure it helps anyway...

 

[ScottyUK]

Hi 7anoter4,

I'm not sure that PE and PUR could be described as LSZH can they? I think it must be a problem specific to the sheath material used in LSZH applications but I'm not sufficiently knowledgable in plastics to know what it might be. Thanks for the input - I'm surprised how little there has been in terms of response to this thread, although that might in itself indicate that brine attack on fibre cable is the stuff of myth and not fact.


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

 

[7anoter4]

Hi Scotty,
There are PE or PUR compounds halogen-free, indeed. The resin is halogen-free but there are also some ingredients as lubricants and stabilizers which have to be halogen free.
See, for example, these:

http://www.lumberg-automationusa.com/con/pdf/61020_R041107.pdf

http://www.hitechcontrols.com/cable...es/intro_pages/introduction_halogen_free.html

The new core and cladding material of fluorinated polymers-containing fluor -a halogen element-are not halogen-free- as one could see.