Patent ID: 7426784

Claim:
A method of assembling a pair of oppositely disposed fire sprinklers on opposite sides of a pair of spaced apart, parallel walls, each wall having an exterior surface and an interior surface, the method comprising the steps of: (a) disposing a main water header line between the pair of walls; (b) disposing at a distal end of the main header line a polymeric pipe fitting having a main branch and at least a first tubular side branch and a second tubular side branch, each of the side branches extending outwardly from a common junction along a common axis, the side branches being co-linear and the main branch being generally perpendicular to the side branches, each of the branches having a distal end opposite from the common junction, the distal ends of each of the side branches having a smooth internal side bore and the distal end of the main branch having a smooth internal main bore to slidably receive a smooth outer end of a length of pipe; (c) providing at least a pair of internally threaded inserts, each insert having interior threads, an outer side surface, an outer rearward surface and an outer forward surface, each outer forward surface of the pair of inserts being adapted to retain respective fire sprinklers at forward ends of each insert along the common axis, so that when the pipe fitting is disposed between the spaced apart walls, a deflector of each respective sprinkler projects from an exterior surface of one of the walls opposite an interior wall surface exposed to the pipe fitting, the outer side surface of each of the inserts being sized and dimensioned so as to closely match the side bores so as to be capable of being slidably and snugly received into one of the side bores at any of a plurality of locations along the common axis within the side bore; (d) disposing an insert within the side bore of each side branch of the pipe fitting while adjusting the depth of each insert within a side bore such that the forward surface of each insert is disposed proximate to the interior surface of one of the pair of walls; (e) retaining each of the at least one pair of internally threaded inserts into a respective side bore; and (f) attaching a fire sprinkler to the interior threads of each insert such that a deflector of each respective sprinkler projects from the exterior surface of each of the spaced apart walls.