We run a building company and want to be able to create a project file in Merlin that says it takes 2 hours to build 1 square Meter of brick work.
Now when scheduling a task of 10 square Meter of brick work, Merlin will know that this task will take 20 man hours. Is this possible?

Yes, this is possible when scheduling your projects with Merlin on Mac OS X. You can create a material resource by a default utilization of 4m^2/day (1m^2/ 2 hours => 4m^2/ 8 hours  )…

…and a task with no work or duration entries on which you assign this ‘brick’ resource. As soon as you enter those 10m^2 as work onto the assignment, Merlin will calculate an expected duration of 20 hours.

That means, you just check the value of expected duration and see how long it would take to build those 10 square Meters.