Welcome! Here are some tips for using this forum.
We are in the process of sizing a boiler replacement for a 1921 school building (now a community center). Presently
has a coal fired 2 pipe steam system from around 1950. Problem is finding EDRs for convectors and fan coils. Have gone through Dan's book "Every Darn Radiator" and did not find them. We will start with the convectors. The enclosures measure 5" deep by 15" high. Inside they are made from 2" steel pipe with 4" square fins, and range from 3.5 ft double row to 27ft single row. Pictures below.