How to Use Codes and Keynotes

The use of Codes and Keynotes has gained popularity in documentation as the benefits become more broadly appreciated. For example CPT1 = Carpet type 1 or RS01 = Roof sheet type 1.

Hobbs + Associates recommends the use of Codes in documentation as a means of reducing likelihood of conflicts and redundancy, and to improve the connection between the specifications and the drawings.

1) Allocate a Code to each material and assembly in the design, both exposed and concealed, such as Insulation.

2) Allocate Codes also to Assemblies which assemblies may consist of other materials which in turn have Codes. For example, a window assembly has code in which the glass and the aluminium finish also have codes. Another example is a set of differing Screen assemblies, which may share infill components which each have a code.

3) Use a Selections Schedule to described the material intended by each code. Columns for a schedule could include the following:

• Code: CPT01
• Label: Carpet Type 01
• Selection: [The particular carpet selection]
• Colour: [Optionally a separate column]
• Supplier: [Optionally a separate column]
• Comments: e.g. “12 week lead time”

4) Adopt a clear and consistent format (syntax) for the Codes. For example:

• Three (or two) CAPS followed by 2 (or 1) digits. e.g. CPT01

5) Abbreviations are different to Codes and can be used in combination with them on drawings. Abbreviations are intended for generic references to materials or elements whereas Codes always refer to a particular selection as described in the Selections Schedule.

• Our recommendation is that Abbreviations are always lower case, no digits are typically 2 to 4 letters in length.
• Familiar and intuitive usage is best, such as dp = downpipe, rwh = rainwater header

6) When developing a set of Codes for your project, consider the difference between “Logical” and “Physical” codes:

• Physical Codes communicate well but should be reserved for projects where selections are unlikely to change. e.g. CPT01 is good but not if the selection gets changed to Vinyl.
• Logical Codes (generic) have the broadest application, particularly where selections may change. e.g. Use CLD01 = Cladding type 01, not CMC01 = Composite Metal Cladding 01
• Logical Codes are also useful in cases where the variety in a range of selections is not yet settled. For example, differing levels of hotel rooms may be allocated differing codes for their carpet selections, even if some of them end up the same. Simply stating that CPT02 is the same selection as CPT01 involves less work than changing a lot of codes.

7) And finally, it pays to be clear what is the purpose of each drawing and add Codes accordingly. For example:

• Show Floor finish Codes only on the Floor Finishes plan and nowhere else. Certainly not on a building section.
• Each drawing has a foreground and a background. Use Abbreviations for the background elements. Use Codes for foreground elements only.

*  Terms: “Codes” may also be referred to as “Keynotes” or “Labels” depending on local practice or the BIM program being used.