In Dan's book I see how important....

.....steam pipe insulation is, especially in the basement.

Mine is 80% insulated, with what seems to be 1/2 inch corrugated cardboard:
-Is this good enough?
-Is corrugated borad an apprioriate insulation or should I replace it?(elbows and tees seem to be asbestos)
-The 20% that is not insulated are the main feeder pipes/risers of the boiler (in an enclosed boiler room) and a misc pipe, here and there in the basement).