An order of precedence is the clause in a contract that ranks the contract documents, so that when two of them disagree everyone knows which one governs. It typically ranks the agreement, the conditions, the specification, the drawings and, increasingly, the model.
At a glance
| Where | The contract's conditions or agreement |
| Ranks | Agreement, conditions, special provisions, specification, drawings, schedules, model |
| Used when | Documents conflict, or one is silent |
| Common rules | Specific over general; large-scale over small-scale; written dimensions over scaled |
| Matters for BIM | Whether the model is a contract document or "for information" |
Typical rules
| Rule | Example |
|---|---|
| Contract documents in a ranked list | Special provisions, then the specification, then the drawings |
| Specific over general | A detail note over a general note |
| Larger scale over smaller scale | A 1:5 detail over a 1:100 plan |
| Written over scaled | A written dimension over one measured from the drawing |
| Later over earlier | A later revision over an earlier one, within the same document type |
Many contracts also say that documents are complementary: what is required by one is required as if by all, and the contractor must report any conflict it finds rather than choose.
How it is used on projects
A coordinator who raises a conflict between a drawing and the model should know which one the contract ranks higher and say so in the issue. The order of precedence doesn't remove the need to fix the conflict; it decides who carries the cost if work was done to the "wrong" one. On BIM projects the BEP and the information protocol should state the model's contractual status: whether it is a contract document, and how it ranks against the drawings.
Variations
- Highway agencies often rank special provisions, then plans, then standard specifications, with written dimensions over scaled ones.
- Building contracts vary: some rank the specification above the drawings, others the reverse.
- Model-based contracts may make the model the primary document, with drawings derived from it.
Common mistakes
- Choosing between conflicting documents on site, instead of raising the conflict.
- Assuming the most recent document governs, regardless of type.
- Never stating the model's status, so its weight is argued after something goes wrong.
- Treating the order of precedence as permission to leave conflicts unresolved.
Where to read more
The conditions of contract used on your project (for example the standard forms published by national contract bodies); the agency's standard specifications for highway work; and the project's BEP and information protocol for the model's status.