Insulation for underground chilled water system

[M.hamalawi]

Dear Experts
We have a chilled water system ( where temperature is around 7 C) including underground piping.
The specifier used Rockwool preformed sections for above ground piping , can we use it for underground system?
What is the best alternative ? PIR preformed sections or PU foam shop applied ?

 

[Lucian]

I'd lean toward PU foam with a proper waterproof jacket. Rockwool can absorb moisture if not perfectly protected which is a major concern below grade.

 

[Vertesol Eustache]

Dear Experts
We have a chilled water system ( where temperature is around 7 C) including underground piping.
The specifier used Rockwool preformed sections for above ground piping , can we use it for underground system?
What is the best alternative ? PIR preformed sections or PU foam shop applied ?

For direct buried chilled water pipework, Rockwool is not generally used as it may absorb water over time. This would result in deterioration of the material and therefore is not ideal for buried pipework. Best used for chilled water piping would typically be a closed cell foam such as PIR, or factory fitted with PU and a suitable waterproof jacketing.