Understanding A Blueprint

Architects working with blueprints in the office.

Understanding A Blueprint

Blueprints, to the untrained eye, can look confusing and overwhelming – there’s so much information on that big page, in such small writing! So, we’re going to make it a bit easier, think of it as Blueprint Reading 101.

What exactly is a blueprint?
A blueprint is essentially the way ideas are communicated between the person designing something (i.e.: an engineer for a product or an architect for a home) and the person who will be physically creating it (i.e.: the manufacturer or the construction firm/contractor).

Are all blueprints the same?
Many professional blueprints will follow a commercial industry standard, but often companies will create their own standards for internal use within the company through drafting prior to submitting (or if submission is not necessary) to the proper jurisdictions for permits or approvals. Regardless of what standard is used, professional blueprints will usually maintain the same basic components.

What follows is a list of the basics you’ll find in a blueprint’s field of drawing:

Title Block, also referred to as the nomenclature
This is usually located on the lower right corner of the drawing and will have:

  • Company’s name (and sometimes address and logo)
  • Part number or name: what part or portion the specific document is – example: “Installation of New Lighting Smith Home Living Room”
  • Sheet # – this is page number
  • Drawing # – the unique identifier as a stand-alone document
  • Size: usually in range A-F with A being the smallest and F being the largest; indicates what size of paper the drawing should be printed on to be true to scale
  • Tolerances: the difference between the lowest and highest acceptable limits of a dimension
  • Scale: indicates the size and scale of the drawing – in other words, how much space on the paper translates to how much space in real life.
    • Usually, first number corresponds to the size on the print, and the second number is the size in “real life.”
      • Example: 1:2 – the drawing is half the size of the actual part
      • Example: 2:1 – the drawing is twice the size of the actual part

Next to (or near) the title block you’ll also (usually) find a signature block, which lists all the signatures required for the drawing to be officially released and published by the creator; signatures and approvals should all be signed – if they’re not, the drawing may not be an official release.

Revision Block: usually in the upper right corner of the drawing – though it’s sometimes attached to the title block – this is a tabulated list of revisions that have changed the original drawing; sequenced A-Z with A being the first revision and Z being the last.

  • In the table, the description will contain the change info and what initiated the change
    • Change orders are what would have initiated a change, and these documents are usually given a number, which will be referenced in the table of the revision block.
  • The revision block will also contain the date of change and the initials/signature of whoever approved it for easy reference if there are any questions

Notes List: these are general notes that apply to the entire drawing such as tolerances, material specs, color specs, testing requirements, and so on. They are found generally around the edges of the drawing.

Flag Notes or Delta Notes: apply only where the flag appears in areas of the drawing – will usually be an actual flag icon (sometimes these take the form of delta notes, and they’ll be indicated by a triangle – a delta). They apply to the specific area noted.

When you look at blueprint, you’re generally (unless otherwise specified) looking at the bird’s eye view of the construction. There are, of course, exceptions to this, such as elevation and cut-away section views.

An elevation view is generally of the outside of the property and will show you what the property will look like if you were to stand directly in front of it and look at it.

Cut away/section views, like elevation views, will give you the view as if you were standing and facing what’s in the drawing, but is usually of interior aspects, such as kitchen cabinetry, window views from inside a room, and so on.

Blueprints have a lot of lines on them – like, a lot. Here are the basics:

  • Zone lines: if you see letters and numbers on the outside edges of the plan that align with the lines, these are zone lines use to break up the drawing into smaller sections for easier reference when notes have to refer back to something. Not all drawing will have this – it’s usually reserved for really large, really convoluted plans.
  • Object lines: the thickest of all lines, these represent the visible sides of the object.
  • Hidden lines: the thin, dashed lines that represent sides of the object not visible to the eye
  • Center lines: very thing, unevenly broken/dashed lines that represent the center of an object – good for determining how things line up.
  • Dimension lines: notate the distance between 2 points, and are characterized by arrowheads at each end.

Of course, you can always just leave it up to our experts to get our hands blue with your blueprints…