Steel galvanized piping with glycols

[Volnei]

Hi Guys,

Does anobody has been facing some problem using steel galvanized piping with Ethylene or Propylene Glycol?

Regards,

Volnei

[aawood1]

Hi Volnei, We had a system put in with galvanized pipe work some time in the past about 16 to 17 years, It started to rust away on the out side at each joint. The system was running with Mono propylene glycol food grade with an exit temp. of 2oC from the Daikin unit. After about 4 years we removed the galvanized pipe work and fitted Stainless steel SHD 10 grade 304 all welded.
Arthur

[US Iceman]

I do not remember ever seeing galvanized pipe used for glycol. The pipe has always been carbon steel or stainless.

[mickmc]

Hello all

Galvinised piping should not be used in a glycol system. After a period of time the glycol can break up and attack the system. The newer Glycols have inhibitors in them to stop attacking the system. glycol should always be mixed with water before adding to system and never added neat.

mmck

[SteveDixey]

Hi Guys,

Does anobody has been facing some problem using steel galvanized piping with Ethylene or Propylene Glycol?

Regards,

Volnei

We had a system on a cold-store floor heater using Mono-ethylene glycol at 30% mix. The headers were steel but the pipes in the floor were polypropylene.

Even with corrosion inhibitors, it still seemed to attack the steel where it leaked out. The galvanising was OK where there was no damage, but any threaded joints or where the galv was damaged suffered.

If the system could be installed with no risk of mechanical damage, I'd look at plastic pipes as a possible alternative if I was putting a new system in.

Steve