Below are photos of sprinkler head corrosion. The heads have been identified as as Grinnell Residential Pendant Sprinkler Head . They were manufactured in 1986 with a temperature rating of 165F. Several of these heads have been sent to UL for testing and to date there has been no recall on these heads. Please check for this type of head in your communities and report any similar corrosion.
(For more information regarding sprinkler head corrosion, please contact Mike Dunton)