Pump construction for typical HVAC applications

[Geby]

I have a question and will appreciate any input. Cast iron, bronze fitted pumps seem to work well for most HVAC applications. As I work to revise my employer’s standard specification for HVAC pumps, I will need to generate a list of any HVAC applications for which special pump construction should be required. All bronze construction for domestic water recirculation pumps is a given. For what applications should partial or full stainless steel construction be required?

Thank You.