Carter Stanfield is co-author of Fundamentals of HVACR. He spent over forty years in HVACR education including serving as Program Director of the Air Conditioning Technology Department at Athens Technical College. You can find more articles by Carter Stanfield at hvacrfundamentals.blogspot.com and hvacrfundamentals.com.
The "magic number" 1.08 is convenience factor. It is a bunch of math combined into one factor as a shortcut, although sometimes more precise calculation is better.
