I was at my buddies yesterday. He has the entire front end off his 69 chevy truck. He did a beautiful job with por15 on the frame. But when he said P.O.R. 15 it took me aback. I always thought it was pronounced like "pour" 15.
We had a sales rep from POR come to our site one time and give us an overview of their products, application tips, etc. and he said it as "P-O-R-15".
After 4 years in a highly corrosive environment with full sun exposure for 12+ hours a day, it was still holding up great. I haven't been back to that site in about 2 years, but I'm guessing that it's still going strong.