Discussion created by jatherton on Apr 19, 2017
Latest reply on Apr 19, 2017 by cdafd

Over the years we have not had an issue with body shops bagging their sprinkler heads in spray booths.  We now have a long time business in town who is refusing to bag the heads based on studies he read documenting a delay in sprinkler activation when bagged.  He is also claiming he is protecting the sprinkler head by "location" as specified in NFPA 33 9.4.7.


9.47 Sprinklers shall be protected against overspray residue

either by location or covering, so that they will operate quickly

in event of a fire. Sprinklers shall be permitted to be covered only by

cellophane bags having a thickness of 0.08 mm (0.003 in.) or

less or by thin paper bags. These coverings shall be replaced

frequently so that heavy deposits of residue do not accumulate



My question is what is the interpretation of the word "location" in section 9.4.7 of NFPA 33? 


My interpretation is the heads in the plenum are not required to be bagged because the are protected by the filters but the heads in the spray booth do, unless they provide manufacture's cut sheets for the booth that through testing on the design of the booth they are not required to be bagged.


Thank you for your assistance