It was the European standard for plate heat exchangers, specifically detailing the design, manufacturing, and testing requirements. It was the bridge between theoretical physics and the cold, hard reality of steel and rubber. But as a student, he couldn't afford the fifty Euros to purchase the official PDF from the Beuth Verlag repository, and the university’s subscription license was currently undergoing a "system update."
Here’s why that’s valuable (and a good feature when looking for the PDF): din en 16984 pdf
Strengths