Definition(s)
Type 2 Open Drains
Type 2 Open Drains are open drains that do not allow an accumulation of flammables above grade; flammables may accumulate below grade, however, due to flammable liquids or heavier-than-air flammable vapors settling into low spot(s) created by the drain or drain piping.
API RP 500, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Division 1 and Division 2, Third Edition, December 2012, Global Standards