Guides

AIA layer standards: how a name is built, the layers you need, and N, E, D

AIA layer standards build every layer name from fields in a fixed order: discipline, major group, an optional minor group, then an optional status. So A-WALL is an architectural wall, A-ANNO-DIMS holds architectural dimensions, and A-WALL-N, A-WALL-E and A-WALL-D keep new, existing and demolished walls apart. The AIA CAD Layer Guidelines are now part of the US National CAD Standard (NCS), which is at version 6.

AIA or NCS: which name to use

People still say "AIA layers" because that's where the convention started. The AIA CAD Layer Guidelines were folded into the US National CAD Standard, and the current edition is NCS version 6. If a client, a consultant or a contract asks for AIA layers, it means the NCS layer name format. Searching "NCS layer naming convention" or "autocad layer standards architectural" lands you on the same thing.

The format is the useful part. Once you know how a name is put together, you can read any consultant's layer list cold and name a new layer without looking it up.

How a layer name is built

A US layer name is Discipline-Major-Minor-Status, with a hyphen between each field. Only the first two are always there.

Discipline

The first letter says whose layer it is. A is the architect, S structural, M mechanical, E electrical. Site layers carry their own designators, as in C-ROAD for roads and L-PLNT for planting. When you take in a structural engineer's DWG, everything they drew sits under S, and you can freeze the lot with one filter.

Major group

This is the thing on the layer, written as a short code rather than a word: WALL, DOOR, GLAZ for glazing, FLOR for floor, FURN for furniture, EQPM for equipment. For annotation the major group is ANNO, and the minor group says what kind.

Minor group

The minor group splits a major group when you need to switch the parts on and off separately. The commonest pair in an architectural set is A-ANNO-TEXT for notes and labels and A-ANNO-DIMS for dimensions. Add a minor group when there's a real reason to control something on its own, not by habit.

Status

The status field goes on the end. It's what turns one wall layer into three on an alteration job, and it gets its own section below.

The layers an architectural set actually needs

The NCS list is long because it covers every building type. Most architectural sets get by on a short core. Start here and add only when something has nowhere honest to go.

Consultants' layers then sit alongside yours under their own letter: S-BEAM for the engineer's beams, M-DUCT for ductwork, E-LITE for lighting. You don't redraw them on A layers. You reference them, and their names tell you whose they are.

The drawing above shows a room at 1:50 on these architectural layers, with a key on the sheet giving each layer's exchange name, its pen and what's on it. A key like that on a cover or legend sheet saves a consultant guessing.

New, existing and demolition: the status suffixes

On a refurbishment the same element can be in three states, and the drawing has to show all three clearly. The NCS does this with a single letter on the end of the name:

• -N new work: A-WALL-N, A-DOOR-N
• -E existing to remain: A-WALL-E, A-GLAZ-E
• -D demolition: A-WALL-D, A-DOOR-D

That gives you sheets from one model. The demolition plan shows the -E and -D layers. The proposed plan shows -E and -N, with -D off. Existing work usually gets a lighter pen and demolition a dashed line, set on the layer so every entity follows.

On new build with nothing existing, most offices drop the status field entirely and use plain A-WALL. Pick one approach for the job and keep to it. A set that mixes A-WALL and A-WALL-N is harder to filter than either on its own.

The rules that make the names worth having

A tidy name on a messy layer doesn't help anyone. Three habits do the real work.

One thing per layer

Put one kind of thing on a layer and name the layer for that thing. A layer called Openings that holds doors and windows both is the wrong layer the day someone needs to turn off only the doors, or count them, or hand them to a door scheduler. That's why A-DOOR and A-GLAZ are separate.

Annotation, dimensions and hatching on their own layers

Keep text, dimensions and hatching off the geometry layers so a drawing can be issued with them off. A consultant who wants a clean background wants your walls, not your room labels. With A-ANNO-TEXT and A-ANNO-DIMS split out, that's two clicks.

ByLayer, unless there's a reason

A layer's colour and pen belong to the layer. Entities stay ByLayer unless they have a reason not to. If half your walls are overridden to a different pen, changing the pen on A-WALL changes only the other half, and the printed set comes out inconsistent.

The ISO version, if you work outside the US

Outside the US the same job is done by ISO 13567. The idea is the same, fields in a fixed order, but the fields are different. The first field is the agent responsible, two characters (A for architect, S structural, E electrical, M mechanical). Then comes the element, six characters, and then the presentation, two characters. Optional fields follow for status, sector, phase, projection, scale and work package.

The pattern is written AA EEEEEE PP. Two things differ from the NCS. The element is a code taken from a published classification such as Uniclass or SfB, not a word. The presentation field says whether the layer holds model geometry, text, dimensions or hatching, for example D for drawing or T for text, so ISO puts the annotation split in its own field where the NCS uses ANNO and a minor group.

If you swap files with a European practice, agree the mapping before the first exchange. An NCS name like A-WALL-N won't mean much to a filter expecting ISO fields, and the other way round.

Setting the layers up in isogram

isogram is 2D CAD for architects and engineers, on Mac, Windows and Linux, and it has layers the way you'd expect. When you open a DWG from a consultant, the layers come in with the drawing, so S-BEAM and M-DUCT arrive named as the engineer named them. It saves DWG in the 2018 or 2004 format, and DXF, so your A-WALL-N goes back out with its name intact.

The practical approach is the one most offices already use. Make the layers once in a drawing, set each one's colour and pen, and start new jobs from that file. Drawings are ordinary files on the disk, so that starting drawing can sit on the office server with everything else.

A-ANNO-TEXT gets easier too. In isogram you set text height as the height on the printed sheet, in millimetres, and the app works out the size on the drawing from the scale, so you don't do the text height sum per viewport. Before the set is issued, isogram reads every sheet for what a senior drafter would catch: lettering too small to print, an empty title block field, two sheets with one number.

A short checklist for the next job

1. Decide NCS or ISO 13567, and write it in the project's CAD notes.
2. Decide whether you need status suffixes. Alterations: yes. Clean new build: usually no.
3. Start from the core list above. Add a layer only when something has nowhere honest to go.
4. Keep text, dimensions and hatching on their own layers.
5. Set colour and pen on the layer and leave entities ByLayer.
6. Put a layer key on the legend sheet so consultants can read your set.

If you want to set up your layer standard in a new 2D CAD, the isogram public beta opens in December 2026 on Mac and Windows, with Linux following in an update, and it's free to test. Join the list and the download link comes by email.

Questions

7 November 2026