I need an opinion on waste vent pipe

I recently performed an inspection and came across a sewer vent pipe next to a wood stove chimney stack. You’ll see in the picture that the vent pipe is discolored. I cannot find any code requirements that pertain to placement near chimneys. Would anyone care to comment?http://www.nachi.org/forum/attachment.php?attachmentid=82931&stc=1&d=1423181860

As a master plumber I can’t think of anything that does not allow this so long as there’s enough clearance for fire rating. It’s not what I would call good practice though.

There may not be plumbing code that addresses this scenario, but it seems like that would be a “violation” of the 3-10-2 rule for chimneys.
Three feet above highest point of roof termination and 2 feet above anything within 10 horizontal feet of the chimney.