Summary for chlorine dioxide on 316 stainless steel Discussion
Chlorine dioxide on 316 stainless steel is discussed as a corrosion problem for a hot water line that failed in 304 stainless. Ray Herring asked whether switching to 316 would better resist a maximum chlorine dioxide strength of 1.1 mg/l. The answer says 316 will be only slightly less prone to corrosion than 304, but chlorine dioxide is still very aggressive: as a powerful oxidizing agent in water, it can attack most metals and break down into oxygen and chlorine, which can ultimately form hydrochloric acid and cause pitting in stainless steel. The practical advice is to consider a plastic alternative instead, with PTFE or poly phenylene oxide suggested as less susceptible materials.
Q. We have been asked to renew a hot water line which has been made in 304 stainless steel and has corroded badly we were thinking of replacing this with 316 stainless steel, would this be any more impervious to chlorine dioxide than the existing line. The maximum strength should be 1.1 milligrams/litre.
Ray Herring
Manager – Swindon, Wiltshire, England
2003
2003
A. 316 stainless steel will be slightly less prone to corrosion than
304, but chlorine dioxide is pretty nasty stuff. It is a very powerful oxidising agent and in an aqueous solution will still attack most metals. It will also break down to oxygen and chlorine, that will ultimately form hydrochloric acid. This will cause pitting corrosion of the stainless. You may want to consider using a plastic pipe (perhaps PTFE or Poly Phenylene Oxide) as an alternative; these should not be so susceptible.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
A. Dear Ray, why do not use titanium. As for chlorine dioxide it is well known the metal is the best choice. See pulp and paper industry plants where titanium is greatly used for bleaching towers and various heat exchanger. Recently I myself delivered the item for Svetogorsk p&p plant, for example. Please decide.
Sincerely your,
Andrey Igolkin
– St.Petersburg, Russia
2004
A. Perhaps the enquirer has got his chemicals mixed up. First, there is reference to hot water, and then to chlorine dioxide at 1.1mg/l. There is no reason to have “chlorine dioxide” in hot water, and you certainly would not use Type 304 in a chlorine dioxide system. I suspect this is simply just hot chlorinated tap water with a
“chlorine” content of 1.1mg/l. The answer is generally, yes, Type 316 will perform better in hot chlorinated tap water with a free chlorine content of 1.1mg/l(ppm).
Hugh Cunningham
– Perth, WA , Australia
2006
A. Chlorine Dioxide is most commonly used for legionella control in domestic water systems. While the concentrations are significantly lower to maintain bacteria control vs. regular chlorine, it does attack 316 leading to heat exchanger failures. The engineer did not ‘mix up’ his chemicals.
Stephen Woolley
– York, Pennsylvania, United States
August 15, 2013
Q. What is the concentration of Chlorine dioxide will be safe for use it to clean copper pipes?
Abood Ftayeh
SAJ GEN – Dubai, UAE
2007