If you dig through the Evans site, you will find a notation that the product can ignite at temps above 240F, but the words flash point are never used, nor will you find an MSDS. Evans also notes that coolant temperatures can rise to 260F under severe operating conditions, and can "safely" rise to 300F. Remember that you will tend to run hotter with non-aqueous PG, the offsetting benefit is that you won't boil over.
Typical flashpoint for PG based anti freeze is in the range of 210F-230F. For example, Amzoil Propylene Glycol flashes at 225F, Bioguard PG 224F, Fleetguard PG 210F, Sierra PG 211F.
Pure propylene glycol coolants will be above their flashpoint under ordinary cooling system conditions. Just think about what you're doing.