Even the most developed layer standard will have missing layers because each project may call for something special. When this happens, you should have general guidelines for creating layers as needed.
Include in your CAD Standard a model for creating layers. The NCS has a great one that reflects the AIA layer guideline.
Your standard may need to go beyond an AIA style, to the “concepts” of layer creation.
Here are a few conceptual ideas you may want to consider outlining in your standard…
1. Use the shortest layer name you can get away with. Use A-WALL and not A-WALL-EXT if the shorter one will work.
2. Only breakdown layer names if you have to turn off one layer and keep another on or change linetype, color or pen weight.
3. Only abbreviate words in layer names that make sense. If you are using AIA style layers and want to shorten the layer name to 4 characters, then make sure it can be deciphered. If you are not using AIA, then you may not have to abbreviate at all.
4. Group layers under the same main area. If you are drawing something for the Ceiling the AIA guideline shows
If you need to break out another Ceiling layer start it with A-CLNG-????