When to measure: depending on how the room is being used, staff should check the measure shown on screen at the beginning of class and at the end and monitor this.
Pryd i fesur: yn dibynnu ar y defnydd a wneir o'r ystafell, dylai'r staff ddarllen yr hyn a ddangosir ar y sgrin ar ddechrau'r wers ac ar y diwedd a monitro hyn.