Exhaust duct Material and Intermittent Hydrochloric Acid Usage

[sdtobin]

I need to specify laboratory fume hood exhaust duct for intermittent usage 25% hydrochloric acid solution. Basically the fume hood and exhaust duct system is for flammable solvents, and the everyone wants to save money. I specified a ETFE lines 304 stainless steel duct however the client wants galvanized exhaust duct. Their hypothesis is the hydrchloric acid vapor is too dilute to ever be an issue. But I need data and evidence to back up their hypothesis. Does anyone have any ideas that could back my clients hypothesis.

Any real world experience or stories related to the formation of zinc chloride? I don't have enough capitol to run a small scale experiment.

 

[rustbuster]

The dew point of HCL is about 54C depending on the concentration of hydrogen chloride. Below this temperature may give you corrosion issues as the HCL will concentrate. Crevices will also give you issues.