Skip to main content

Building Definition

This section describes how to define the building for the project. The room definitions are used for indoor photometric calculations. They can also be used to label circuits in distribution equipment schedules.

tip

You do not need to model the building in your project if you are not going to use the features the building model provides.

Common Building Definition Information​

The values that can be specified for floors and rooms within a building are listed below. Some values can be set in the room schedule only. Others can have a default set in the schedule that can be changed for individual floors or rooms.

Schedule-Only Settings​

This section describes room values that can only be set in the schedule. These cannot be changed for individual rooms. If you need to include a room that has a different setting for one of these values, you must create a new record in the schedule.

  •  Lighting Power Density: The watts per square foot allowed in the room according to the local energy code.

  •  Illuminance Category: ▾ The illuminance category for the group as defined in the IESNA Lighting Handbook. The categories are based upon the type of task being performed in the area. Lower letters correspond to lower foot-candle levels. Higher letters correspond to higher foot-candle levels.

Individual Floor and Room Settings​

This section describes building definition values that be changed for individual floors and rooms. The value in the room schedule is the default value.

  •  Room / Room Number: The name of the room.

  •  Room Type: ▾ The room type taken from the room project schedule. Determines the default settings for the room. See the Room Project Schedule section for more information.

  •  Floor: ▾ The floor with which the room is associated, which can affect the ceiling height and room cavity ratio. See the Floor List section for more information.

  •  Area: The area of the room in square feet. This value is based upon the room outline inserted on the drawing. To change the value, you must change the room outline.

  •  Room Cavity Ratio: The room cavity ratio (RCR) is a measure of how effectively light fixtures will illuminate the room. It is calculated based upon the geometry of the room using the following formula:

    RCR=(Ceiling Height−Workspace Height)×PerimeterArea×2.5RCR = (Ceiling\>Height - Workspace\>Height) \times {Perimeter \over Area} \times 2.5

  •  Description: The description of the room. The default value is the Room Type ▾.

  •  Ceiling Height: The height of the ceiling for this room. The default is set in the floor definition. See the Distance Input Format section for more information about specifying this height.

  •  Workspace Height: The elevation of the workspace above the floor level. Used to calculate the room cavity ratio for indoor photometric calculations. See the Distance Input Format section for more information about specifying this elevation.

  •  Foot-candles Desired: The amount of light that needs to be provided in the room.

  •  Wall Cavity Reflectance: The reflective value of the walls in the room type. Used to calculate the coefficient of utilization of the fixture for indoor photometric calculations. See the Edit Indoor Lighting Level Schedule List section for more information.

  •  Effective Ceiling Cavity Reflectance: The reflective value of the ceiling in the room type. Used to calculate the coefficient of utilization of the fixture for indoor photometric calculations. See the Edit Indoor Lighting Level Schedule List section for more information.

  •  Effective Floor Cavity Reflectance: The reflective value of the floor in the room type. Used to calculate the coefficient of utilization of the fixture for indoor photometric calculations. See the Edit Indoor Lighting Level Schedule List section for more information.

  •  Dirt Depreciation Factor: The factor by which indoor photometric calculations are reduced due to dirt in the room.