science

ISO 128

ISO 128 is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand ISO 128 rather than just read about it. In short: ISO 128 is the International Organization for Standardization (ISO) standard covering the general principles of presentation in technical drawings, specifically the graphical representation of objects on technical drawings. Overview Since 2003, the ISO 128 family has expanded to fifteen parts, which initiated between 1996 and 2003.

Key takeaways

ISO 128 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect ISO 128 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of ISO 128 from memory before moving on to harder problems.

Reference excerpt

ISO 128 is the International Organization for Standardization (ISO) standard covering the general principles of presentation in technical drawings, specifically the graphical representation of objects on technical drawings.

Overview Since 2003, the ISO 128 family has expanded to fifteen parts, which initiated between 1996 and 2003. The standard begins with a summary of general rules for the execution and structure of technical drawings. It then describes basic conventions for lines, views, cuts and sections, and different types of engineering drawings—including mechanical, architectural, civil, and shipbuilding. ISO 128 applies to both manual and computer-based drawings, but not to three-dimensional CAD models. The ISO 128 series replaced the earlier DIN 6 standard for drawings, projections, and views, first published in 1922 and updated in 1950 and 1968. ISO 128 itself debuted in 1982 as a 15‑page document specifying general presentation principles for orthographic projection methods. Several parts of ISO 128 have been updated individually, and new parts were added (e.g., Part 15 in 2013). The most recent revisions were published in 2020 and 2022.

Composition

Current parts ISO 128-1:2020 Technical product documentation (TPD) — General principles of representation — Part 1: Introduction and fundamental requirements ISO 128-2:2020 Technical product documentation (TPD) — General principles of representation — Part 2: Basic conventions for lines ISO 128-3:2022 Technical product documentation (TPD) — General principles of representation — Part 3: Views, sections and cuts ISO 128-15:2013 Technical product documentation (TPD) — General principles of presentation — Part 15: Presentation of shipbuilding drawings ISO/TS 128-71:2010 Technical product documentation (TPD) — Simplified representation for mechanical engineering drawings ISO 128-100:2020 Technical product documentation — General principles of representation — Part 100: Index

Withdrawn parts Replaced by ISO 128-2 2020 ISO 128-20:1999 — Basic conventions for lines ISO 128-21:1997 — Preparation of lines by CAD systems ISO 128-22:1999 — Conventions for leader lines and reference lines ISO 128-23:1999 — Lines on construction drawings ISO 128-24:2014 — Lines on mechanical engineering drawings ISO 128-25:1999 — Lines on shipbuilding drawings Replaced by ISO 128-3 2022 ISO 128-30:2001 — Basic conventions for views ISO 128-33:2018 — Representation of views, sections and cuts in construction drawings ISO 128-34:2001 — Views on mechanical engineering drawings ISO 128-40:2001 — Conventions for cuts and sections ISO 128-43:2015 — Projection methods in building drawings ISO 128-44:2001 — Sections on mechanical engineering drawings ISO 128-50:2001 — Conventions for representing areas on cuts and sections

Related ISO standards

ISO 129 Technical product documentation (TPD) — Presentation of dimensions and tolerances ISO 129-1:2018 — General principles ISO 129-4:2013 — Dimensioning of shipbuilding drawings ISO 129-5:2018 — Dimensioning of structural metal work ISO 216 — Paper sizes (e.g., A4) ISO 406:1987 — Tolerancing of linear and angular dimensions ISO 1660:2017 — Geometrical tolerancing ISO 2203:1973 — Conventional representation of gears ISO 3098-1:1974 — Lettering — Part 1: Currently used characters ISO 5455:1979 — Scales ISO 5456 Technical drawings — Projection methods ISO 5457:1999 — Sizes and layout of drawing sheets ISO 7519:1991 — Principles of presentation for assembly drawings ISO 8015:2011 — Fundamentals of geometrical product specifications

References

Further reading Giesecke, Frederick E. (2021). Technical Drawing (15th ed.). Pearson Education. pp. 423–448. ISBN 9780134306414. Smith, Angela (2019). "A Comparative Study of ISO 128 vs. ANSI Y14.5 in Technical Drawings". Engineering Graphics and Design. 45 (2): 112–127. doi:10.1234/egd.v45i2.2019 (inactive 16 July 2025).{{cite journal}}: CS1 maint: DOI inactive as of July 2025 (link) Lee, Hyun (2022). "International Standards for Technical Drawings: A Review". Procedia Manufacturing. 51: 1034–1041. doi:10.1016/j.promfg.2022.10.162 (inactive 16 July 2025).{{cite journal}}: CS1 maint: DOI inactive as of July 2025 (link)

External links ISO 128‑1:2020 – General principles of presentation at ISO

Illustrations

Worked examples

Example 1 — a first encounter with ISO 128

Start with the simplest possible case. Write down what ISO 128 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to ISO 128 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about ISO 128 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of ISO 128

In research: ISO 128 appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses ISO 128 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: ISO 128 is common in secondary-school and first-year university syllabi. It links to neighbouring topics ISO standards, Technical drawing, so understanding it makes those chapters shorter.
In everyday life: Look for ISO 128 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study ISO 128 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what ISO 128 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain ISO 128 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is ISO 128 in simple terms?

Why does ISO 128 matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study ISO 128?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on ISO 128.