The following links/documents are all publicly available. They demonstrate the need for listed special gas vent as a life-safety issue. 

Centrotherm Documents

Flue Gas Venting for Residential Heating Appliances
By Doug Page

OEM Manuals & White Papers

Charlotte Pipe and Foundry Company - Should Plastic Pipe & Fittings Be Used to Vent Combusation Gasses?

North American Pipe Corporation - Solvent Welded PVC Pipe - Aboveground Applications

Technical Documents

Massachussetts Public Health Advisory: Plastic Pipes Used in Venting

Trade Journal Articles

PHCP Pros - Is PVC an Acceptable Vent Material for Flue Gas?

by Ron George

PCHP Pros - PVC Flue Pipe Failure
by Ron George

Plumbing & Mechanical - How Do You Vent?
by Jim Molloy

PCHP Pros - Venting Systems
by Doug Page

Healthy Building: PVC In Buildings: Hazards and Alternatives