Came across this a few months ago at a drywall estimate. House had been gutted and someone was attempting to run the B-vent up the corner of a bedroom and box it in. Not sure what the specific problems with this are exactly, but it doesn’t seem wise to bury the pipe connections inside of a wall. Not sure what came of this project.
What are the problems with this water heater vent
Welcome to the InterNACHI community, Michael.
Gas Water Heater Vent Codes & Standards
15 water heater venting checkpoints
2: Supports. Vertical/horizontal.
Type B gas vent is routinely installed in a chase. There are rules to follow for strapping and supporting, fire stopping, etc.
That’s exactly how my vent was installed in my house built in 2002. Not a problem.
I have since installed a HE furnace and a WH with a power vent so I opened it up, removed the vent pipe, installed shelves, and now have an extra linen closet.
I don’t see a problem in your photo.