Drawing to Conclusions

Hello BIMfans,
During the development of my information models, I have considered a lot of different aspects, including Mindful Modelling, Open data and Producing with Purpose.  However, these information models aren’t the only deliverable I should be concerned with.  I will also need to produce documentation, such as COBie and, more importantly, drawings.

Yes, drawings are still needed when following BIM processes!

To produce objects for my information models, there are standards such as the BS 8541 Series, to produce COBie there are standards such as NBIMS 4.2 and BS 1192-4, but what about for producing drawings?  In fact, there are a lot of supporting standards that cover the various elements of drawing production including:

Paper Sizes:

As I wanted to create several drawings including plans, elevations, and sections, I needed a readily available paper size (that didn’t require a large format plotter), so I chose A3. A3 is a standard size, 297x420mm, specified within ISO 216. The beauty of the A-series is that they are easily scalable; doubling in size as you go up the series.  This is because they are based on √2.  I’d love to explain this to you in detail, but Numberphile have kindly already done this for me!

Now that I’ve chosen my paper size.  I need to define my drawing border.

Drawing Border:

There is an international drawing border specified within ISO 5457. It states that the drawings space for an A3 sheet is 277x390mm; giving 20mm clearance on the left to allow for filing and 10mm of clearance on the remaining sides. It also states that drawing borders should have centre lines, a grid system and trim markings; which when combined, look like this:

I like the specified ‘A3’ the corner to indicate the paper size, but to be honest, this feels a little over the top; no matter it’s in the ISO!

Now that I have a drawing border, I need to add a title block.

Title block:

There is an international set of title block fields within ISO 7200ISO 7200 covers all document headers and title blocks, meaning that it is applicable to anything from drawings and calculation sheets to splash screens and metadata.  It states that the following fields are mandatory:

  • Legal owner;
  • Identification number;
  • Date of issue;
  • Segment/sheet number;
  • Title;
  • Approval person;
  • Creator; and
  • Document Type.

In addition to these, I also want to include several of the optional fields including project name, document revision, document status, and technical reference from an expanded list within EN 82045-2 which specifies metadata for document management.  This will not only allow me to comply with ISO 7200, but also capture additional information that I wish to share.

Now how should I arrange these fields?  Originally, I had created a horizontal title block but ISO 9431 states that the title block space is also used for text notes. Wanting to keep this space to a minimum, I have =produced a vertical title block to the minimum specified width of 100mm.


Note:  To better align with ISO 19650-2 I have changed Technical Reference to ‘Checked by’ and renamed Approval Person and Creator as ‘Approved by’ and ‘Created by’ respectively.

Note:  This is also my splash screen to ensure that I manage models using the same metadata have I use for drawings and other deliverables.

Now that I have a title block, I just need to add my text notes.

Space for Notes

The space for notes on drawings is specified within in ISO 9431ISO 9431 states that there should be a space, the length of the title block, for three kinds of notes:

  • Explanations (notes that help read the drawing);
  • Instructions (notes on how to use the drawing); and
  • References (notes on supplementary drawings and documents).

Under explanations, I’ve added a note on general tolerances as specified within ISO 2768, a note on dimension units as specified within ISO 129-1 and a note on symbols as specified within BS 8541-2.  Under instructions, I had added ‘do not scale’, however I am aware that many planning authorities do not accept drawings with this note.  Because of this I have instead used ‘Responsibility is not accepted for values obtained in scaling from this drawing’.  Under references, I’ve included a schedule of relevant drawings.


There is an international font for CAD drawings specified within ISO 3098-5.  As you are no doubt aware, no annotation is complete without a good font, for CAD there is no font better than the ISOCP fonts (These fonts come preinstalled in most CAD software).  These fonts are Sans-Serif (without serifs), and looks like this:


Putting all of these elements together, I get the following super-ISO title block:

At A3 the notes section looks quite large, it looks much better on A1 drawings!

Now that I have put all of these standards together, I am able to complete my drawings; producing the following for Tŷ Digidol:

NOTE:  All of these international standards are also conveniently summed up in a single British Standard, BS 8888.  Thank you John Ford for letting me know!

And there we have it, by thinking about how to produce my drawings, I have been able to apply several international and national standards to produce an internationally consistent drawing border and title block.  This is a big help towards the completion of PLQ2.5!

Model Generation:
2.1 What existing information is available?
2.2 Is there sufficient information to produce a BEP?
2.3 What is the layout of the house?
2.4 What assets are contained within?
2.5 What asset information can be linked to the graphical model?

Now that I have a system for producing each deliverable in place, It’s about time I shared them with you…

6 thoughts on “Drawing to Conclusions

  1. I guess you could say why should people design their own northpoints, but similarly you could say why standardise it? Standardising infers that there is one ‘right’ way or a good reason to do it one way, there isn’t one right way when it comes to taste and design, I would hate to see someone come and paint your walls a standardised BS 4800:2011 colour (I checked, there is a BS for paint colour). I’m all up for standardising fire alarm symbols, because no one benefits from people inventing their own arcane symbology, but north points? Surely not.


    • Hi Henry. I agree with you that there is no ‘right’ way but firmly believe there should be just one way.

      What’s the difference between North Points & Fire Alarm Symbols? They are both symbolic representations. Unless we standardize these items, the message can be lost. Doing a quick google of North Points, some of them are useless! Obviously, there is flex in what colour you paint with, but we have standard terms for colours through CMYK, RGB, and Hex codes; so not even colours escape standards conformity.

      I guess my point is that why make a new North Point is the National Standard clearly points to North?


  2. If we are debating what’s right or wrong – have we missed the point?

    Why re-invent the wheel? Why spend time designing a new CAD/BIM standard when you can use the existing one?

    Wouldn’t you rather focus your time on tasks that add value to your customer?


    • Exactly. When you consider time to create, maintain and train others on how to use them, making your own standards is a very expensive process!


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