According to the regulations of the building contractors can work from 8.00 am - 6.00 pm.,
without noise if it violates a penalty 5,000 Bht. (pleases let me know) and after 6.00 pm. can work with noise.
But in this case to service to Keyence, the building has cooperate with the contractors to start any work after 21:00 pm. for permanently.