What is this standard about?
This engineering drawing standard is part of the large BS 8888 family of standards on technical product documentation and specification. BS EN ISO 5458:2018 establishes new rules on pattern specifications and on combining some individual specifications. It’s one of more than 200 ISO GPS standards in use across the manufacturing sector.
Who is this standard for?
It will typically be used in the aerospace, defence, automotive, rail and nuclear sectors but is equally applicable to any engineering or manufacturing organization needing to produce engineering drawings in 2D or 3D. Users will be:
- Mechanical engineers
- Design engineers
- Manufacturing engineers
Why should you use this standard?
The BS 8888 family of standards helps users specify and therefore manufacture products more accurately and unambiguously.
This standard establishes complementary rules to BS EN ISO 1101 to be applied to pattern specifications. It also defines rules to combine individual specifications for geometrical specifications using the symbols POSITION, SYMMETRY, LINE PROFILE and SURFACE PROFILE, as well as STRAIGHTNESS (where the toleranced features are nominally coaxial) and FLATNESS (where the toleranced features are nominally coplanar).
These rules apply when a set of tolerance zones are grouped together with location or orientation constraints through the use of the CZ, CZR or SIM modifiers.
What’s changed since the last update?
The 1998 standard has been updated and brought into line with recent revisions to other key geometrical tolerancing standards, particularly BS EN ISO 1101:2017.
The main changes are:
- Rules have been harmonized to align it with BS EN ISO 1101
- Unstated rules in the previous edition have been removed
- The concept of “pattern” to control all types of geometrical features has been introduced more generically, rather than applying it only with the position symbol
