Block and Zone Dimensions

Combined constructions

The diagram below illustrates how blocks should be defined and how zone volumes and surface dimensions are derived from the parent block when using Combined constructions.

The important things to note are:

The length/width dimensions of the block are measured from the outside of external walls.
The height of the block is the floor-floor height:

For ground floor blocks, the block height is the distance from the ground level to the underside of the floor slab of the next block up.
For non-ground floor blocks, the block height is measured from the bottom of the block floor slab to the bottom of the floor slab of the block above.

Flat roofs are placed on top of the block, so when drawing a block with a flat roof you should exclude the roof construction in the height.
External floors are placed under the block, so when drawing a block with an external floor you should exclude the external floor construction thickness in the height.
Wall surfaces extend the full height of the block.
Zone surface dimensions (shown in green dotted lines above) are measured from inner edges of outer walls and the centre line of partitions.
Floor surfaces extend horizontally to the inner surface of external walls and to the centre line of partitions. See below for more on zone/surface dimensions.

Show diagram for Separate Constructions

The zone volume used in ventilation calculations is the actual inside volume (shown in yellow in the diagram above). These inside zone surface dimensions are used to define surface heat transfer areas in simulations and other calculations.

Zone perimeter (plan view)

Other related information

See Combined Constructions for information on the meaning of the Construction Model data.
Also see Constructions for how to edit the construction configuration.
And the Model Geometry Example section for a detailed worked example illustrating how surface areas and volumes are calculated.