Drafting conventions: notations, terms, and abbreviations

Based on National CAD Standard 3.1

Notations

PDF pp. 366-371

Notations, or notes, are needed on working drawings where the graphic images, by themselves, cannot convey the required information. A notation may apply to the whole set of drawings (or documents), to a particular discipline (e.g.., architectural drawings and specifications), or may only apply within an individual sheet or drawing.

Some guidelines for notations:

be brief and concise;

use notes for identification primarily, with more elaborate descriptions and instructions left to the specifications;

use generic terms, rather than brand names (e.g., gypsum board rather than "sheetrock");

try not to use abbreviations (see below);

use the same terms in drawings and specifications: be consistent;

in general, do not direct particular contractors to do specific work (with some exceptions); and do not direct the "sequence" of construction (as this is generally the contractor's prerogative);

avoid repetitive notes;

it is generally unnecessary and redundant for drawing notations to refer to the "specs," as the specifications are already a part of the construction documents;

especially in schedules and tables, keep notes brief, using single terms where possible.

Identification of spaces:

Rooms: number rooms, with the first part corresponding to the floor number, and the second part numbered in order starting from the most important point of access (e.g., the front door, or the elevator lobby), and continuing in a clockwise direction. An example of a third-floor room number would be 304.
Stairs: Assign "Stair 1" to the most prominent stair and/or the one with the greatest egress capacity. Stair 2, Stair 3, and so on are named by moving in a clockwise direction on the first floor (or presumably the egress level), with stairs keeping the same names on all other levels. Other stairs that may not come down to the first floor are numbered next.
Exterior spaces: number such things as balconies, porches, etc. unless there is only one.
Elevators: Elevator 1 is closest to the building entrance with largest capacity; then continue the numbering moving clockwise within elevator banks.
Shafts: Shaft 1 (same principle as with elevators, starting with shaft closest to biggest entry).

Identification of objects:

Doors: have the same identification number as the (secure-side) room they open into; if one room has multiple doors, use 304A, 304B, etc. moving clockwise from the corridor access door. Specific information about the door is contained in a "door schedule." Glass in and around doors is classified as follows: if in the door, the door schedule describes it; if in a sidelight, it is part of the door frame and is so noted where door frame types are described.
Windows: Unlike doors, which are individually named, windows are organized by "type." See "symbols" in week 6 and "schedules" in week 14.
Louver types: each type is designated by an identifier (see "symbols" in week 6).
Furniture, fixtures, and equipment: use alphanumeric designations in the plan, with a "legend" to identify the object.

Cross-referencing:

The organization of information begins with the floor plan. From this drawing, we reference sections, elevations, interior elevations, large-scale plans, and plan details. Avoid redundancy by keeping notations in a single location (e.g., in a detail, but not in the section). The idea of a mock-up set (see week 8) helps.

Cross-reference other drawings where such information is helpful, but be somewhat selective, avoiding obvious cross-references (as in: see elevation for position of window in facade...)

As mentioned previously, identify each drawing and each sheet with a unique identifier.
cross-referenced plans

The cross-referencing can continue, if necessary, with additional details keyed in from the "detail" itself.

Terms and abbreviations

PDF pp.427-605

Use abbreviations only to improve clarity, or to save time and space: do not abuse the privilege. Spell out words whenever possible.

In general, do not abbreviate any word of 5 letters or less, except where useful for formatting schedules.

Some abbreviations refer to multiple words. This is OK where the variations occur in different disciplines, but not OK if it is likely to cause confusion within a single discipline. In the latter case, spell it out.

Either reference the UDS [uniform drawing system] Terms and Abbreviations, or create your own list derived from the UDS.

Note that the UDS also contains words that should not be used, often because a different word, or phrase, is preferred. So, drywall is superseded by gypsum board (GYP BD).

Notations

PDF pp. 801-

Purpose of notations:

information
identification
instruction

Types of notes:

GENERAL NOTES:
apply to entire work, show up on "G" sheets; need not be repeated subsequently on different drawings.

GENERAL [discipline] NOTES:
Appear on first, or "0"-series sheets (that is, general sheets containing symbols legend, notes, etc.: see week 2 notes) within a particular discipline, and do not duplicate general notes. They might, for example, contain references to the drawing conventions specific to a discipline. The example given in the UDS is:

TOP OF STEEL ELEVATIONS INDICATED ARE BASED ON A FINISH FLOOR ELEVATION OF 30M (100'-0") -- SEE SHEET C-101 FOR ACTUAL DATUM AND BENCHMARK INFORMATION
Note that this contradicts the general preference of using the imperative mood for instructions. But the line between "information" and "instruction" can sometimes be fuzzy. As an imperative instruction, one could say, instead: BASE TOP-OF-STEEL ELEVATIONS ON FINISH FLOOR ELEVATION OF 30M (100'-0") -- SEE SHEET C-101 FOR ACTUAL DATUM AND BENCHMARK INFORMATION

GENERAL SHEET NOTES:
Write such notes in the "imperative mood" as in recommended "specification" language: direct commands, requests, and prohibitions without the second-person "you" included. So, for example: "LABEL ALL DRAWINGS."

REFERENCE KEYNOTES:
Instead of, or in addition to, textual messages, reference keynotes identify graphic representations with specific specification sections. Example from the UDS is: 01 56 00.A01 - TEMPORARY DUST BARRIER TYPE 1.

The last 3 characters are user-defined suffix and modifiers (A.01) which allow references of multiple keynotes within the same specifications section. See PDF p.814 for image example.

SHEET KEYNOTES:
These notes are indicated with a hexagonal symbol that contains the note's number inside and a leader from the hexagon that points to the item being described. An example would be a note that says: "ALIGN FACE OF NEW WALL WITH COLUMN CENTERLINE." Within the drawing itself, the hexagon symbol (with appropriate number inside) would then be used to identify applicable walls. In this way, the note itself does not need to be repeated over and over again. See PDF page 815.

The first three are not directly linked to graphic representations; if they appear on the same sheet, they are ordered as shown above.

The language of notes:
In general, use imperative mood, and not indicative mood:

Avoid: "CONTRACTOR SHALL NOT SCALE DRAWINGS"
Preferred language: "DRAWINGS: DO NOT SCALE"

A summary of grammatical "moods" can be found here.

If reference to the specifications is deemed useful, be specific, e.g., "SEE SPECIFICATION SECTION 08 10 09.13."

Use capitalized, proportional, sans-serif, non-stylized fonts.