Patent ID: 7614198

Claim:
A method for providing flow restrictors for a substantially flat roof with existing roof drains, comprising the following steps: locating an existing roof drain on a substantially flat roof; and setting a flow restrictor directly on the roof, the flow restrictor having a flange with an upwardly extending wall connected thereto and having portions defining at least one rectangular aperture passing through the wall, the aperture extending upwardly a first distance in the wall, and the wall extending upwardly from a base to a top, wherein the top of the wall defines an overflow opening and wherein the flange encircles the wall and extends at least a second distance radially outwardly from the base of the wall, wherein the step of setting the flow restrictor on the roof comprises positioning the flow restrictor on the roof so the wall surrounds the roof drain and any drain guard associated with said roof drain, such that the flow restrictor does not overlie the roof drain and any drain guard associated therewith, the so placed flow restrictor serving to restrict the flow of water entering the drain such that the flow restrictor is supported directly by the roof, and is not attached to the drain or fixed to the roof using fasteners which can puncture the roof and cause roof leaks.