This question seeks answers with one of the following as supporting evidence: International standards, other standards widely recognized in multiple areas of the United States, or sound building and engineering principles.
Note: If there is a preferred material for the vent line in this application, I would also greatly appreciate a recommendation. As a theoretical example: "Use PVC instead of galvanized steel because PVC will help to insulate against the heat of the chimney."
Why I ask this question:
As part of a basement remodel, I need to upgrade an existing plumbing line and add venting through the roof for the fixtures it serves.
There is a roughly 4" gap between a brick chimney (which provides the exhaust for my furnace and hot water tank) and one of the walls all the way to the attic.
This leaves enough room for a 2" waste vent line and a roughly 2" air gap if I were to run the vent line by the wall next to the chimney. Then, I do not have to drill any new holes in floors or ceilings to add the vent line. However, I realize that the methane gas from waste is combustible and running something combustible that close to a hot chimney could make it a bad idea.