BOQ item characteristics vs quantity calculation rules: the characteristics column must not stipulate calculation rules; supplementary rules belong in the BOQ calculation-rules statement and become contract terms

Topic Positioning

A recurring BOQ preparation and measurement dispute: can calculation rules be stipulated in item characteristic descriptions? Answer: characteristics and calculation rules are parallel independent elements; the characteristics column is not the place for rules; supplementary rules legally belong in the "calculation rules statement (preparation notes)" made part of the tender/contract documents, applying as contractual agreement.

Core Conclusions

1. Characteristics and rules stand apart, each with its own source

1. The five elements: GB 50860-2013, 4.2.1 (mandatory): "BOQs are prepared per the annexes' item codes, names, characteristics, units, and calculation rules." Commentary: the five elements are indispensable.
2. Characteristics' function: 4.2.4 (mandatory): "Item characteristics shall be described per the annexes combined with the actual project." Commentary: characteristics are "the indispensable basis for fixing a unit rate" — accurate and complete; principles: per the annexes and the project, sufficient for pricing; standard atlas/drawing references may replace descriptions where complete, with text supplementing the rest. GB/T 50875-2013, 2.1.14: "Item characteristics: the essential features constituting the value of a work/measure item."
3. Source of calculation rules: GB 50860-2013, 4.2.5 (mandatory): "Listed quantities are computed per the annex rules." GB/T 50854-2024, 4.2.6: "per the rules of Annexes A-Q of this standard." The legal carrier is the standard's annexes, not the characteristics column.

2. The lawful path for special measurement calibers: rules statement + contract

• GB/T 50500-2024, 7.1.1: "Contract works are measured per the work the contractor completed and that is due to be measured. Quantities per the national and industry calculation standards agreed by the parties and supplementary calculation rules."
• GB/T 50500-2024 Annex D, D.4.1 (rules statement) table note: "Where national/industry standards are adopted, name them and their numbers; where rules are supplemented, set out the detailed rules." — into the rules statement, not the characteristics column.
• GB/T 50500-2024, 4.1.7: under either contract type, work-section BOQ codes, names, characteristics, units, and work contents are prepared per the standards and supplementary rules; measure items per the standards; where characteristics cannot be described, list work content and names.

3. Hierarchy of measurement bases (contract first)

• T/ZBD 100.4-2023, 4.3.1: "Where the parties expressly agreed calculation rules, the appraiser measures per them; absent agreement, per the national standard matching the contract type; absent that, per current industry or local standards." (Example: floor-area disputes first fix the contract type — construction contracts use GB/T 50353; real-estate sales use GB/T 17986.)
• GB/T 51262-2017, 5.5.1: "Where drawings are complete and the parties dispute the measurement basis, appraise per current national measurement rules; absent national, industry/local; unless the contract agreed otherwise."

4. Why not in the characteristics column

• Descriptions are confined to annex characteristics — "standard, concise, accurate, complete", serving unit rates; rule text is not a "characteristic" and does not override conflicting standard annexes;
• Incomplete descriptions are "BOQ defects" with risk allocation per GB/T 50500-2024 (unit-price: employer bears, repriced per actual characteristics; lump-sum: contractor bears) — stuffing rules into characteristics invites "characteristic mismatch/BOQ defect" disputes;
• Sole acceptable exception: where the annex itself asks a caliber to be clarified, a clarifying statement consistent with the standard may appear, but never contradicting the annex rules.

Applicable Boundaries

• Applies to BOQ preparation, tendering, settlement, and cost appraisal for building/decoration and structures; core bases GB 50860-2013, GB/T 50854-2024, GB/T 50500-2024.
• "Contract first" governs measurement-basis disputes; contracts must not violate mandatory law or depart materially from tender documents.
• In appraisal, first classify the contract type, then choose the standard.
• This card does not compute specific quantities — see each standard's annexes.

Further Reading

• GB 50860-2013 Chapter 4, 4.2.1, 4.2.4, 4.2.5 and commentary.
• GB/T 50854-2024, 4.2.6 and Annexes A-Q.
• GB/T 50500-2024, 4.1.7, 7.1.1, Annex D (D.4.1).
• T/ZBD 100.4-2023, 4.3.1; GB/T 51262-2017, 5.5.1; GB/T 50875-2013, 2.1.14.