Which fields belong in the estimate basis?
Record the tender revision, drawing list, measurement rules, currency, tax treatment, labour basis, supplier quote status and commercial assumptions. Separate facts from decisions and unresolved items.
| Field | Example | Reason |
|---|---|---|
| Document basis | Drawing and revision list | Controls scope |
| Quantity rule | Measured from plan | Explains takeoff |
| Rate basis | Supplier quote or approved library | Shows source |
| Allowance | Defined missing input | Shows uncertainty |
| Exclusion | Outside stated battery limit | Prevents ambiguity |
Sources: Construction Specifications Institute: MasterFormat 2026
How should estimate changes be tracked?
Keep a change log with the changed source, affected rows, previous value, new value, reason and reviewer. Addenda and design development should not be folded into a new total with no explanation.
- Source change
- Quantity change
- Rate change
- Scope decision
- Commercial adjustment
What is not an estimate basis?
A single total, a screenshot without sources or a generic cost-per-capacity figure is not enough to review a project estimate. Data center topology and project scope vary, so the basis must stay tied to the issued information.
Sources: Telecommunications Industry Association: ANSI/TIA-942 Telecommunications Infrastructure Standard for Data Centers, Uptime Institute: Tier Standard: Topology
Common questions
What else should the bid team know?
Does a checklist produce a complete estimate?
No. It controls the review. Quantities, rates, scope and commercial treatment still need project inputs and estimator approval.
Can data center work be estimated from the room name alone?
No. Use the issued drawings, schedules, specifications, interfaces and equipment information. A room label is not a quantity basis.
Who approves engineering assumptions?
The responsible project engineer approves technical design assumptions. The estimator controls the pricing treatment and records the source.
Primary sources
- MasterFormat 2026Construction Specifications Institute
- NFPA 70, National Electrical CodeNational Fire Protection Association
- ANSI/TIA-942 Telecommunications Infrastructure Standard for Data CentersTelecommunications Industry Association
- Tier Standard: TopologyUptime Institute