Nope...... I think there is a term for what is shown, just been to long ago.cda were you thinking of the term electrolysis or galvanic reaction? These occur when two dissimilar metals are in contact with each other and cause a mild chemical reaction.ZIG
As mentioned common in areas with high humidity' date=' chlorine or other chemical exposure (factories/industries) open air etc. all the more reason for those approving or reviewing sprinkler plans to point the need to proper heads for atmospheric conditions............... and when inspecting to require replacement with "special heads"[/quote']The last picture is in a grocery store!!! Guess the bananas could be off gasing?
The white one?The first picture is definitely a galvanic reaction caused by dissimilar materials. The second is more difficult to determine due to the paint covering everything but could be the same issue. In fact even a component of the paint could cause that. paintZIG
Factory finishIsn't the head painter white or is that just me? I can see the dust well enough but the head looks as white as everything around it.
Typically one will need to investigate what chemicals, ventilation and moisture development is in an area displaying head(s) with these conditions. In the "grocery" environment one should evaluate their misting of produce and air exchanges/ventilation in an area of affected heads. I most commonly see this in pool chemical areas or refrigeration areas served by an ammonia supply source. Regardless, upon discovery the applicable party will need to replace heads in area with special heads in accordance with the referenced standard NFPA 13/25.......... or IFC is not using references to previous. I have also seen microscopic pin hole leakage around the cap seal that reactive chemicals in the water supply didn't like the head's copper cap.The last picture is in a grocery store!!! Guess the bananas could be off gasing?