undergound air pipeline coating

[kkp3456]

Dear experts,
one of our underground utility air line (SA 53) was leaked & the patch replacement was done. now the earlier line had Ca2SiO4 wrapped with some black plastic on it. but as per specs for underground piping, it says
primer PE; wrapping PE & mastic coating bitumastic 50

which one can be followed?

 

[unclesyd]

I like the Bitumastic Coatings myself as we have had very good results with them though there is nothing wrong with the other two mentioned. If you use a Bitumastic product make sure you check for holidays with a something like a Bird Dog".
I would have the failure examined from the point of view as to whether Cathodic Protection might be of value. A good across the board Cathodic Protection Company is Corrpro.

You also may want to look over the materials offered by someone like Denso.

http://www.corrpro.com/Default.aspx

http://www.densona.com/Denso-News.aspx