Let’s start with this, that can be life saving for some somewheres.
Both propane and natural gas burning appliances routinely use PVC pipe as a vent. Not true
High efficiency appliances do not need any other type of vent in many cases.
Power vents are almost always constructed of PVC pipe.Not true
Don’t see anything particularly wrong here…even with the height above the roofline.Height of vent through roof holds true as it would for a regular chimney.
Propane manufacturers have their own set of rules that do not necessarily need to meet Fuel Gas Codes for vent height. Read again.
Check the manufacturer’s installation instructions.10-4
Equipment, material, or services included in a list published by an organization that is acceptable to the AHJ and concerned with evaluation of products or service, and whose listing states that either the equipment, material, or service meets appropriate design standards and been tested and suitable for a specified purpose.
Hope this clairifies a few things.