The object attached to the pipe in these photos seems to be a vent (such as described in Hissing vent on a steam heating pipe).
It hisses a lot, and you can see on the ceiling above a brown stain has formed over time. Is this a normal thing to happen with one of these? Is it just rust particles or something to be more concerned about?
Assuming this is just a cosmetic problem and not one of health, is there any way to prevent this from occurring? e.g., is this a sign that the vent needs to be cleaned or replaced?
Thanks
