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Drawing Numbers


The drawing number system identifies a building, the computer files for a building, each drawing in a file, and each sheet of a drawing.


Number structure

A computer file number has the format BRF where B is the building number, R is the revision digit, and F is the file digit. A drawing number has the format BRFL where L is the layer digit.

Building number

The building number B has four digits:

Revision digit

The revision digit R starts at 0. When a building is revised, the revision digit is incremented.

File digit

The file digit F identifies a particular file for the building:

  1. not used
  2. floor and schematic plans
  3. foundation plan, roof plan, and elevations
  4. reverse floor and schematic plans
  5. reverse foundation plan, roof plan, and elevations
  6. not used
  7. not used
  8. not used
  9. not used
  10. not used

Layer digit

Floor plans and schematic plans

  1. meta layer - green
  2. first story room layer - black
  3. first story floor layer - red - floor plan digit
  4. first story schematic layer - blue -schematic plan digit
  5. second story room layer - black
  6. second story floor layer - red - floor plan digit
  7. second story schematic layer - blue- schematic plan digit
  8. basement room layer - black
  9. basement floor layer - red -floor plan digit
  10. basement schematic layer - blue -schematic plan digit

The meta layer has title block information, drawing legends, and guidelines. A room layer is a minimal floor plan.

A floor plan is created by combining the meta layer with the room and floor layers of the story. A schematic plan is created by combining the meta layer with the room and schematic layers of the story. In two story buildings, the second story plans are sometimes added to the first story plans.

Foundation plan, roof plan, and elevations

  1. meta layer - green
  2. foundation plan - black -foundation plan digit
  3. foundation plan sheet 2 - black
  4. not used - green
  5. roof plan - red - roof plan digit
  6. not used - green
  7. elevations - blue -elevations digit
  8. elevations sheet 2 - blue
  9. elevations sheet 3 - blue
  10. elevations sheet 4 - blue

The drawing number uses the foundation plan digit, roof plan digit, or elevations digit as the layer digit. All sheets of a drawing have the same drawing number.

The meta layer has title block information and guidelines. A drawing sheet is formed by combining the meta layer with one of the other layers.

If a drawing has more than one sheet, each sheet is labeled "Sheet S of N" where S is the sheet number and N is the number of sheets. For a foundation plan, sheet 2 has the layer digit 2. For elevations sheet 2 has the layer digit 7, sheet 3 has the layer digit 8, and sheet 4 has the layer digit 9.