Free reference
Symbols legend
47 symbols, each one drawn here by the same code that draws it on a sheet rather than by a picture made for this page. If the renderer changes, this legend changes with it, which is the only way a legend stays true to the drawings it describes.
How to use this page
A symbol is a word. Read the shape first, then the contents, then follow it to whatever it points at: a schedule, a legend on the sheet, or another drawing. Most of the symbols below carry a number or a mark, and that mark is almost always a key into something else rather than an answer on its own.
Every set carries its own legend on a general sheet near the front, and where a project legend differs from this one, the project legend governs. Read it once at the start of a job.
Walls and openings
Exterior wallCut by the plan, so it is drawn heavy and filled. The width of the band is the real thickness of the wall.
Interior partitionThe same construction at a smaller thickness. A partition simply reads thinner than an exterior wall.
Door, single leafLeaf and arc. The end the leaf hangs from is the hinge side, and the arc is the floor the door needs to open.
Door, pairTwo leaves and two arcs meeting at the middle of the opening. The schedule width is one leaf, not the pair.
Door, slidingThe leaf runs alongside the wall instead of sweeping across the opening, so there is no arc to read.
Elevator hoistway doorTwo short leaves in the shaft wall with no swing at all, because the doors part sideways.
WindowThe wall thickness carried across the opening with a glazing line through it. No leaf and no arc.
Grid and structure
Grid line and bubbleA centre line with a lettered or numbered bubble at the end. It is a reference, not a piece of building.
Steel columnThe shape of the section seen from above, drawn at its real size. A wide flange column reads as a capital I.
Concrete column or pierA filled rectangle at the grid intersection. Solid rather than shaped, because the section is solid.
Match lineA heavy dashed line where a drawing runs off the sheet, labelled with the drawing that continues past it.
Break lineThe drawing carries on past this point and the boring part has been cut out to fit the sheet.
Dimensions and annotation
Dimension with slash ticksExtension lines, a dimension line, slash ticks and the computed number. The ticks are the architectural habit.
Dimension with arrowheadsThe same anatomy with arrows instead of ticks, used where the run is short or the ticks would crowd.
Leader noteAn arrow at the thing being named, an elbow, and a note. Used where there is no schedule to send you to.
KeynoteA hexagon holding a short key with an arrow at what it describes. The key resolves in a legend on the sheet.
Tags
Room tagThe room name over its boxed number. The number is the address every schedule and finish uses.
Door tagA hexagon holding the door number, with a leader to the opening. It is a key into the door schedule.
Window tagA diamond holding a type mark such as W3. Several windows can share one mark, because it names a type.
Callouts and cross references
Section markerDrawing number over sheet number, with a tail and an arrow giving the direction of view after the cut.
Detail bubbleThe same split bubble without a cut. A dashed boundary shows how much of the drawing the detail covers.
Interior elevation markerFour arms, one per wall of a room, each carrying its own drawing number. One symbol, up to four drawings.
Sheet furniture
North arrowBelongs to the drawing, not to the sheet, because two plans on one sheet can be rotated differently.
Bar scaleDrawn at the scale of the view, so it shrinks with the print. It is the honest statement of scale.
Drawing titleThe drawing number and its name, underlined, under the drawing. The numerator of every callout to it.
Revisions
Revision cloudDrawn around the part of the drawing that changed. It says where, and says nothing about when.
Revision triangleThe number of the revision that made the change, tying the cloud to a row in the revision table.
Consultant symbols
DuctTwo parallel lines at the real width of the duct, with the inside size in inches, width first.
PipeA single line with its size and service. Hidden where it runs below the slab, and often carrying a slope note.
Duplex receptacleA power outlet. The thin line joining it to others is a circuit, not the route the conduit takes.
SwitchControls the fixtures it is linked to. What it switches is read from the electrical plan, not from the ceiling plan.
Lighting fixtureA fixture in the ceiling. Its type and position are on the reflected ceiling plan; its circuit is on the electrical plan.
Ceiling diffuserWhere supply air enters the room. It appears on the ceiling plan for position and on the mechanical plan for airflow.
Smoke detectorA ceiling mounted detector. Its spacing is a code question and its wiring is on the electrical drawings.
PanelboardWhere circuits terminate, tagged with its own designation. The panel schedule lists every circuit on it.
ThermostatThe control point for a zone. Which equipment it commands is read from the mechanical plan and schedule.
Materials in section
ConcreteA scatter of marks and dots. On a plan it appears at slabs and pads; on a section it does most of the talking.
Brick or masonryA running bond pattern. On a wall section it marks the outer leaf, with the cavity drawn behind it.
InsulationA soft looping band. Its thickness on the drawing is its real thickness, which is why it needs a large scale.
EarthUndisturbed ground, drawn below a footing or behind a foundation wall so the cut reads as buried.
Screened backgroundA light uniform tone. On a consultant sheet it means the geometry belongs to somebody else's drawing.
Fixtures and casework
Water closetDrawn at its real size in plan, which is what makes a clearance in a toilet room checkable on the drawing.
LavatoryA washbasin. The plumbing plan gives its supply and waste; the plan gives where it is and how much room it has.
Drinking fountainSmall and easy to miss, and worth finding because it projects into a corridor and eats clear width.
StairTreads with a direction of travel and, at the cut, a break where the flight passes through the plan.
Elevator carThe car inside the shaft, with the hoistway doors in the shaft wall. Both appear on every level plan.
ShelvingCasework drawn at its real footprint, so the aisle left between runs can be read straight off the plan.