The first thing to clarify is that there is no specific ‘sprinkler head Rule in golf’ as such. Rather, sprinkler heads are classed as immovable obstructions, and it is Rule 16 governing these that clarifies when and how you can take free relief from them.
Immovable obstructions are one of four things classified as abnormal course conditions under the Rules, with the other three being animal holes, ground under repair and temporary water.
