There may be situations where you require a large number of rooms in a project but are met with system constraints. Consideration of this this document should help.
Bentley Hevacomp V26 has a limit of 32,000 rooms - however you may still be constrained by the number of zones/surfaces that the SBEM calculation engine (used in PartL) can handle.
From the iSBEM manual:
It is strongly recommended that you back up project before continuing with this document.
You should have your project in a state where all unique floors and at least one example of a floor that can be duplicated are extant. In the instances where you have drawn more floors than you require, you should delete the duplicate floors.
From our model, we can delete floors 2, 3, and 4 as they are duplicates of the 1st floor. This will leave us with unique floors only; Ground floor, 1st floor and top floor. The next step is to break out of CAD input mode and apply room multipliers where applicable.
You may wish to make a further back up of your project at this stage
To break out of CAD input mode you should close CAD Input and select the Room Data option from the main Design Database menu. When first selected you will be presented with a warning letting you know you will be turning of CAD input. Un-tick the option and then select OK in the dialog that appears.
Once this is done you will be presented with a list of rooms in the project rather than the warning message.
If you enter Room Data mode you should be aware of a number of limitations. Please see this document for further information
From the available rooms, select one of the rooms you wish to apply a multiplier to. In this instance, Room 10 is one of the rooms that can be multiplied for floors 2, 3 and 4.
Once the room is selected, click on the Room Data tab and enter the required multiplier in the highlighted input box. Click back to Select room to save your changes and then select the other rooms you wish to apply a multiplier to, and continue modifying the Room multiplier accordingly.