What would be the secondary piping in an ice rink?

[tommybearass]

What would be the secondary piping in an ice rink? This was part of a question on the BC refrigeration IP, they were asking what type of hangers would one use on secondary piping?
Chair hangars, lay it in the sand, lay it on the concrete, and another answer i cant remember.

[rmuntz]

Rediculous !!
My guess would be, brine piping, lay it in the sand.?