Standard CAD Layers for Architectural Drawings

Drawing layers are the primary way CAD software organizes graphic information and controls that information’s visibility. With layers, drafting is easier because different layers can be identified with different colors. Line weights can be associated with layers in order to help printed drawings to read better. Layers can be turned off or on to overlay information or produce additional drawings.

Why follow national standards?

Although there is some initial time investment in learning the standards, it’s very likely that some form of it will be used in your office. Developing company standards for anything has its benefits, but here are some specific advantages to creating CAD standards.

  • Saves time by eliminating the guesswork on how to organize a drawing
  • Create a template with drawing standards in place can allow you to get started quickly
  • Establishes a graphic quality so drawings can look consistent
  • Team members (inside and outside of the office) are familiar with the drawing structure and can access information more efficiently
  • Easier for consultants and users outside of your organization to use your CAD files

Does the AIA establish CAD standards?

Not exactly. The American Institute of Architects established “CAD Layer Guidelines” for the first time in 1990. In 1997, the AIA decided to collaborate with the National Institute of Building Sciences to combine the “CAD Layer Guidelines” and NIBS’s “National CAD Standard”. These two organizations continued to work with other groups, like the Construction Specifications Institute (CSI), to further develop the U.S. National CAD Standards for Architecture, Engineering, & Construction into what it is today.

Version 6 is the current iteration of the National CAD Standards. More information can be found here.

Layer format

When naming layers, the following format is used:

Discipline Designator – Major Group – Minor Group – Minor Group – Status

Discipline Designator: Indicates discipline (civil, fire protection, plumbing, survey, etc.)
Major Group: Indicates major building system (door, glazing, furniture, roof, etc.)
Minor Group: Further defines the building system
Status: Indicates the phasing (existing, demo, new, temporary, etc.)

The first two parts (discipline designator and major group) are required. The following three can be used to better describe the layer and are optional.

Note: “X” in the tables below is a placeholder for any letter.

Architectural Discipline Designators
Designator Description
A Architectural
AS Architectural Site
AD Architectural Demolition
AE Architectural Elements
AI Architectural Interiors
AF Architectural Finishes
AG Architectural Graphics
AJ User-Defined
AK User-Defined
Architectural Layer List
Layer Name Description
AX-XXXX-FNSH Any major group: finishes
AX-XXXX-CASE Any major group: casework
AX-XXXX-FIXT Any major group: plumbing fixtures
AX-XXXX-GRID Any major group: grid
AX-XXXX-SIGN Any major group: signs
AX-AREA-OCCP Area: occupant or employee names
AX-CLNG-ACCS Ceiling: access
AX-CLNG-OPEN Ceiling: openings
AX-CLNG-TEES Ceiling: main tees
AX-CLNG-SUSP Ceiling: suspended elements
AX-CONV Conveying systems
AX-DOOR-FULL Doors: full-height (swing and leaf)
AX-DOOR-PRHT Doors: partial height (swing and leaf)
AX-EQPM Equipment

Equipment: access

AX-EQPM-FIXD Equipment: fixed equipment
AX-EQPM-MOVE Equipment: moveable equipment
AX-EQPM-NICNEquipment: not in contract

Equipment: overhead

AX-FLOR-CASE Floor: casework
AX-FLOR-EVTR Floor: elevator cars and equipment
AX-FLOR-HRAL Floor: handrails, guard rails
AX-FLOR-LEVL Floor: level changes, ramps, pits,depressions
AX-FLOR-OTLN Floor: outline
AX-FLOR-OVHD Floor: overhead (objects above)
AX-FLOR-RAIS Floor: raised
AX-FLOR-RISR Floor: stair risers
AX-FLOR-WDWK Floor: architectural woodwork
AX-FURN Furnishings
AX-FURN-FILE Furnishings: file cabinets
AX-FURN-FIXD Furnishings: fixed in place
AX-FURN-FREE Furnishings: freestanding
AX-FURN-PLNT Furnishings: plants
AX-FURN-PNLS Furnishings: system panels
AX-FURN-SEAT Furnishings: seating
AX-FURN-STOR Furnishings: system storage
AX-FURN-WKSF Furnishings: system work surface
AX-GLAZ Glazing
AX-GLAZ-FULL Glazing: full-height
AX-GLAZ-PRHT Glazing: partial-height
AX-GLAZ-SILL Glazing: window sills
AX-HVAC-SDFF HVAC: supply diffusers
AX-HVAC-RDFF HVAC: return air diffusers
AX-LITE Lighting fixtures
AX-ROOF-HRAL Roof: handrails
AX-ROOF-LEVL Roof: level changes
AX-ROOF-OTLN Roof: outline
AX-ROOF-RISR Roof: stair risers
AX-ROOF-STRSRoof: stair treads, ladders
AX-WALL-CAVI Walls: cavity
AX-WALL-CNTR Walls: centerline
AX-WALL-FIRE Walls: fire wall
AX-WALL-FULL Walls: full-height
AX-WALL-HEAD Walls: door and window headers
AX-WALL-JAMB Walls: door and window jambs
AX-WALL-MOVE Walls: moveable partitions
AX-WALL-PRHT Walls: partial-height
AX-WALL-PATT Walls: texture or hatch patterns

There are a few other layers used to organize the drawings that can help indicate the type of drawing or annotations used throughout the drawing.

View & Annotation Layer List
Layer NameDescription
XX-XXXX-IDENIdentification tags
XX-XXXX-LEGNLegends, symbold keys
XX-XXXX-MARKMarkers, break marks, leaders
XX-XXXX-NPLTNon-plotting graphic information
XX-XXXX-RDMERead-me layer (non-plot)
XX-XXXX-REFRReference, external files
XX-XXXX-REVCRevision clouds
XX-XXXX-SYMBReference Symbols
XX-XXXX-TITLDrawing or detail titles
XX-XXXX-TTLBBorder and title block

How to use CAD standards in your practice

Whether you work alone or in an office, there are a few steps you should consider taking if you haven’t already. You should definitely start by setting up a template. Create a CAD file with all of the layers, colors, and line types set up. Create a plot style to go with it. This way, you can open it at the beginning of any project and be ready to go. Investing some time up front can pay dividends in the long run.

As you work on more projects, you’ll know what works well, what blocks you use, etc. and can build up a library. The more tools you have at your fingertips, the quicker you can put a set of drawings together.

Don’t have the time to put something together? Not sure where to start? There are a number of options out there to buy pre-assembled drawing templates that often have title blocks, CAD blocks, dimension styles, etc. ready to go.

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