Data Labelling / Data Engineering

Hello Deep Learning Community,

I have been trying to apply ML to lab data. All the categories in the data set are in hours (starting from 0) and they are ordered in ascending order. for example, the value of the first column is 5 hours and the next coulm is 7.3 and so on.

My questions are:

Since everything is in hours and they have an order, how should I deal with the data (Nominal, Ordinal…)?

There are a lot of null values which are NaN on purpose, meaning nothing was recorded in that category. How should I impute them without jeopardizing the structure of the dataset?

I would be grateful if someone could help me with this matter.