Filtering time stamped data

[Mroy]

Hello all,
I have about 3 years’ worth of temperature data from 3 different levels of a building. They are all time stamped and recorded at about 15 minute’s intervals round the clock.
Does anybody know of a way to filter the data and get the working hour temperatures?
Working hour was defined as from 8am to 5pm.

I have attached an abbreviated file as the original is too large
Would appreciate any help,

Roy