An environmental control system, comprising: a first environmental control system component; a second environmental control system component; and a drain arrangement comprising: a duct with an interior and an exterior, and wherein the duct extends between the first environmental control system component and the second environmental control system component; a first orifice through the duct; an extension in the form of a cylindrical boss extending from the exterior of the duct and surrounding the first orifice; the extension comprising a first plenum in serial fluid communication with the first orifice and an orifice device removably connected to the extension, the orifice device comprising a second orifice in serial fluid communication with the first plenum and the first orifice, respectively; wherein the first orifice and the first plenum extend along a first axis (A E), and the second orifice extends along a second axis (A D), that is parallel to the first axis and offset from the first axis by a distance; characterised in that the orifice device further comprises: a third plenum in serial fluid communication with the second orifice; and a third orifice in serial fluid communication with the third plenum wherein the third orifice is positioned in a baffle that is connected to the orifice device. a first environmental control system component; a second environmental control system component; and a drain arrangement comprising: a duct with an interior and an exterior, and wherein the duct extends between the first environmental control system component and the second environmental control system component; a first orifice through the duct; an extension in the form of a cylindrical boss extending from the exterior of the duct and surrounding the first orifice; the extension comprising a first plenum in serial fluid communication with the first orifice and an orifice device removably connected to the extension, the orifice device comprising a second orifice in serial fluid communication with the first plenum and the first orifice, respectively; wherein the first orifice and the first plenum extend along a first axis (A E), and the second orifice extends along a second axis (A D), that is parallel to the first axis and offset from the first axis by a distance; characterised in that the orifice device further comprises: a third plenum in serial fluid communication with the second orifice; and a third orifice in serial fluid communication with the third plenum wherein the third orifice is positioned in a baffle that is connected to the orifice device. a duct with an interior and an exterior, and wherein the duct extends between the first environmental control system component and the second environmental control system component; a first orifice through the duct; an extension in the form of a cylindrical boss extending from the exterior of the duct and surrounding the first orifice; the extension comprising a first plenum in serial fluid communication with the first orifice and an orifice device removably connected to the extension, the orifice device comprising a second orifice in serial fluid communication with the first plenum and the first orifice, respectively; wherein the first orifice and the first plenum extend along a first axis (A E), and the second orifice extends along a second axis (A D), that is parallel to the first axis and offset from the first axis by a distance; characterised in that the orifice device further comprises: a third plenum in serial fluid communication with the second orifice; and a third orifice in serial fluid communication with the third plenum wherein the third orifice is positioned in a baffle that is connected to the orifice device. a third plenum in serial fluid communication with the second orifice; and a third orifice in serial fluid communication with the third plenum wherein the third orifice is positioned in a baffle that is connected to the orifice device.