Technical Drawing Standards: Line Type Definitions.

The advantage of using the British standard is that the line type definitions have largely been coordinated in their meanings across the Industries.

Putting the Line typesLine weights and Line type scales together, we get the following Line type Definitions to use in our drawings.

I have amalgamated the definitions from the engineering drawing supplement and the construction drawing supplement together. The Line type definition numbers are my own.

Once again, you are free to make up your own line definitions, but it is recommended that you put a note on the drawing with their meaning.

BS ISO Standard line types

BS 8888:2008 Technical product specification.

BS EN ISO 128-20:2001 Technical drawings. General principles of presentation. Basic conventions for lines

BS ISO 128-23:1999 Technical drawings. General principles of presentation. Lines on construction drawings

BS ISO 128-24:1999 Technical drawings. General principles of presentation. Lines on mechanical engineering drawings

4 Responses to “Technical Drawing Standards: Line Type Definitions.

  • Keith S. Angus
    12 years ago

    So what are all these ACAD_ISO linetypes that we are offered? Which ISO, and why? Which industries are they used in? I’m not aware of any standard that calls them up, and find I have to write my own line definitions to get anything sensible. Surely in these days of worldwide standards that shouldn’t be necessary? (I’m trying to decide if I’m serious or joking when I say that – but I really can’t make my mind up!)

    • Hi Keith,

      This is from the ACADISO.lin file (2010):

      ‘ISO 128 (ISO/DIS 12011) linetypes have been added.
      ;; The size of the line segments for each defined ISO line, is
      ;; defined for an usage with a pen width of 1 mm. To use them with
      ;; the other ISO predefined pen widths, the line has to be scaled
      ;; with the appropriate value (e.g. pen width 0,5 mm -> ltscale 0.5).’

      I have no idea how much time and effort the CAD vendors spend keeping up to date with current standards!


  • Anonymous
    13 years ago

    The Line weights ought to be in the ratio three:2:1. The additional line weight for construction drawings is used to represent graphical symbols and is situated somewhere between the a Narrow Line and a Wide  line.