He won't be at work for another half [an] hour.
The cancer test requires at least half [an] hour to finish.
Is 'an' required in the sentences above?
Thanks in advance!
In the first one, you can leave it out. He won't be here for another 15 minutes, for another half hour, for another two hours.
In the second one, you need it. It takes half an hour, it lasts half an hour, etc.