Overview
SIST EN ISO 5455:1998 - Technical Drawings: Scales is an international standard developed by CEN, based on ISO 5455:1979, that establishes guidelines for the selection, designation, and use of scales on technical drawings in all fields of engineering. This standard provides clear definitions of scale types, recommended scale ratios, and the proper method of scale inscription, ensuring clear communication and consistency in engineering documentation worldwide.
Key Topics
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Recommended Scales: SIST EN ISO 5455:1998 sets out a table of preferred scale ratios for enlargement, full-size, and reduction on technical drawings. These include:
- Enlargement scales: 50:1, 20:1, 10:1, 5:1, 2:1
- Full size: 1:1
- Reduction scales: 1:2, 1:5, 1:10, 1:20, 1:50, 1:100, 1:200, 1:500, 1:1000, 1:2000, 1:5000, 1:10000
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Scale Designation: The standard specifies that each scale should be clearly designated using the term “SCALE” followed by the ratio (e.g., SCALE 1:1, SCALE 2:1, SCALE 1:10). If the context is clear, the word “SCALE” may be omitted.
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Definitions:
- Scale: The ratio between the length of an element in the drawing and its real-world counterpart.
- Full size: Ratio 1:1, where the drawing matches the actual size.
- Enlargement scale: Ratio greater than 1:1.
- Reduction scale: Ratio less than 1:1.
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Inscription Guidelines: The main scale used should be inscribed in the title block of the drawing, while additional scales for detail views should be indicated next to the relevant part or reference.
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Clarity and Interpretation: The chosen scale should allow for clear and easy interpretation of all relevant information. If necessary, detail views can be drawn at larger scales for clarity.
Applications
SIST EN ISO 5455:1998 is widely applied in various engineering fields requiring precise and standardized technical drawings, such as:
- Mechanical Engineering: For component manufacturing, assembly diagrams, and part documentation.
- Civil and Structural Engineering: For architectural plans, site layouts, and infrastructure documentation.
- Electrical and Process Engineering: Ensuring that circuit diagrams and process layouts are clearly understood by stakeholders.
- Education and Training: As a reference for students and professionals learning technical drawing principles.
The use of standardized scales improves the accuracy and international compatibility of technical drawings, supporting efficient communication between engineers, manufacturers, and clients.
Related Standards
When working with technical drawings and scales, the following related standards provide complementary guidance:
- EN ISO 7200: Technical product documentation - Data fields in title blocks and document headers
- EN ISO 128 series: General principles of presentation in technical drawings
- ISO 129: Technical drawings - Indication of dimensions and tolerances
- ISO 5456 series: Projection methods in technical drawings
Conclusion
Adhering to SIST EN ISO 5455:1998 ensures the correct and uniform use of scales in technical drawings, helps prevent misunderstandings, and promotes international collaboration across engineering disciplines. Implementing this standard is essential for anyone involved in the creation, interpretation, or management of technical documentation.
