# Engineering Precision Standards

**Version:** 1.0 · **domainXpert Domain Reference Guides**

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## Overview

Engineering contributions must be numerically precise, unit-consistent, and standards-aware. Vague or unit-free claims are annotation errors in this domain.

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## Units and Dimensions

- Always include units. "A force of 500" is not an acceptable claim. "A force of 500 N" is.
- Use SI units as the default. If using imperial units, state them explicitly and consider providing SI equivalents.
- When tolerances matter, state them: "25 mm ± 0.1 mm."

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## Standards References

When a claim depends on a standard, cite it:
- ISO standards: ISO [number]:[year]
- ASTM standards: ASTM [designation]-[year]
- IEEE standards: IEEE Std [number]-[year]
- ASME standards: ASME [code]-[year]

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## Tradeoff Documentation

Engineering decisions involve tradeoffs. When evaluating or writing responses about design choices:
- State what is being optimized
- State what is being sacrificed
- Note the conditions under which the tradeoff changes

Example: "Increasing wall thickness improves burst pressure but adds weight and material cost. For this application, the pressure requirement dominates."

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## Safety Factors

Always note when a calculation or recommendation involves a safety factor. State the factor and its basis.

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*For questions, contact your engineering domain coordinator.*