Winters coming
 

If you look up the hold over tables after de icing you'll usually see the time quoted as '15:45' meaning between 15 and 45 minutes.
I deduse that 15mins is the min hold over and 45 is the max...depending on precipitation and severity of accumulation...but exactly how do you scientifically interpolate these values?

Does your company Ops Manual give any guidance, or do you know of a certification rule?

The Holdovertimes in the tables are valid from light(-) to moderate conditions of precipitation. They are not applicable to heavy(+)conditions. There is no way to scientifically interpolate as they are also influenced by various other criteria.( Wind, Jetblast, Aircaft skintemperature.......)

FBN