Finned tube trench convector drawings from 1954.

Some snippets from a 1954 drawing set for a Masonic campus. It has this cool finned tube trench convector below a massive wall of (single pane) windows. The plan shows it at 191 sq. ft. (I assume that's EDR). 2" supply, reduces to 1-1/2 for the return trip in the trench, then to 3/4" condensate return. This trench is still in use today, but they got rid of all the steam in the 2000s so there's a hot water fin tube there now.