Basic blueprint reading · Lesson 1 of 4

Basic blueprint reading: principles and terminology

What a drawing set is, how a sheet identifier and a callout bubble lead you from a plan to a detail, how dimension lines and feet-and-inches are read, what an AFS shop drawing carries, and the safety boundary for field checks.

You will be able to: Name the parts of a drawing set (sheet identifier, title block, revision marks, callout bubbles, views and dimension lines) and read a feet-and-inches dimension, and say when a field check at an edge needs fall protection first.

12 min · 12 slides · 9 questions

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Slide 1 of 12

A drawing set and its standard

In this course, a drawing set is the group of drawing sheets issued for one project, and every sheet carries its own sheet identifier.

The National CAD Standard (NCS) is a consensus standard, and its publisher lists Version 7 (2024) for licence.

CSI says the NCS includes its Uniform Drawing System (Modules 1-8); the standard is paid, so your set's own legend governs.

Sources

United States National CAD Standard (NCS): the NCS is a consensus standard; NCS Version 7 (2024) is licensed single, site or enterprise - National Institute of Building Sciences
National CAD Standard: its three parts and the eight modules of the Uniform Drawing System - Construction Specifications Institute

Videos for this lesson

What this video shows: An individual educator's overview of reading construction drawings: page designations, line types, abbreviations, symbols, general notes, elevations and cross sections, schedules and where to find a scale. Checked against the video's description.

Video: Reading Construction Drawings - 10 Minute Crash Course by H’s Construction Crash Courses, on YouTube. Chosen from the video's published description.

Glossary

Sheet identifier: The code on a drawing sheet made of the discipline designator, the sheet type designator and the sheet sequence number, as in the National CAD Standard (Version 6, Uniform Drawing System Module 1); A-201, for example, is an architectural sheet of elevations.
Callout bubble: A circle on a drawing that points to another view: the upper half gives the view or detail number and the lower half gives the sheet where it is drawn.
Revision cloud and delta: A scalloped outline around a change after issue, tagged with a numbered triangle that matches an entry in the sheet's issue and revision block.
Dimension line: A fine, dark, solid line with an arrowhead on each end that shows the direction and extent of a dimension; extension lines run out from the feature it refers to.
Cutting plane line: A very heavy line on a drawing that shows where the object is sliced to make a section. Your set's legend shows how it is drawn and which way the section is viewed.