Seal for obstructing migration of particulates and precipitation between a perimeter of a pipe stick/pipeline passage through a wall of a pipe fusion chamber and circumferential surfaces of pipe sticks/pipelines of various diameters within a selected range of diameters to be passed therethrough, the seal comprising: a frame contiguous with a perimeter of the passage (E in) and defining an opening therein; and a plurality of sheets of cloth each having an inner edge and an outer edge, each of said inner edges, with said plurality of sheets of cloth taken together in overlapping serial relationship about a perimeter of said opening and covering said opening, overlapping an anticipated center axis of a pipe stick/pipeline to be passed through said opening; said inner edge of each said sheet of cloth being at least twice as long as a distance across said opening taken along its respective inner edge in its pipe stick/pipeline center axis overlapping condition; said outer edge of each said sheet of cloth being pleated and fixed to said frame and said inner edge of each said sheet of cloth being gathered on an elastic band; each said elastic band having a free state length equal to its respective distance across said opening and being elastically stretchable to said length of its respective said inner edge, ends of each of said elastic bands being fixed to said frame at points determining said length thereof; whereby, when a face of a pipe stick/pipeline to be passed through the seal is aligned on said anticipated center axis and pushes said plurality of sheets of cloth away from said frame, said pleats and said elastic band cooperate to allow said inner edges of said plurality of sheets of cloth to slide over the face and hug substantially the entire outer circumference of the pipe stick/pipeline. a frame contiguous with a perimeter of the passage (E in) and defining an opening therein; and a plurality of sheets of cloth each having an inner edge and an outer edge, each of said inner edges, with said plurality of sheets of cloth taken together in overlapping serial relationship about a perimeter of said opening and covering said opening, overlapping an anticipated center axis of a pipe stick/pipeline to be passed through said opening; said inner edge of each said sheet of cloth being at least twice as long as a distance across said opening taken along its respective inner edge in its pipe stick/pipeline center axis overlapping condition; said outer edge of each said sheet of cloth being pleated and fixed to said frame and said inner edge of each said sheet of cloth being gathered on an elastic band; each said elastic band having a free state length equal to its respective distance across said opening and being elastically stretchable to said length of its respective said inner edge, ends of each of said elastic bands being fixed to said frame at points determining said length thereof; whereby, when a face of a pipe stick/pipeline to be passed through the seal is aligned on said anticipated center axis and pushes said plurality of sheets of cloth away from said frame, said pleats and said elastic band cooperate to allow said inner edges of said plurality of sheets of cloth to slide over the face and hug substantially the entire outer circumference of the pipe stick/pipeline.