As an example, take into consideration duct cleaning machine with 20m flexible driller shaft. When there is 3m from the floor to the ventilation, then from one entry point you can clean 17 meters in one direction and 17 in the other, in total 34m. These calculations are applicable to flexible driller shaft of any length. In our range you may find flexible driller shafts length 3-20m.
For ventilation access, we recommend cutting hatches every 10-20m. This length makes it easy access for the cleaning process and inspecting the results.