Posted by Harold Kestenholz - Hydronic Network on December 19, 2001 at 13:49:30:
In Reply to: five square foot of heating surface boiler standard posted by Joye Chizek on December 18, 2001 at 10:45:01:
I suspect the change came about when fuels started changing from coal to oil and gas about that time. The boiler manufacturers would have decided upon the change. SBI IBR GAMA ASME etc.