Why concept-stage estimates drift
Early estimates are usually built in a separate spreadsheet: equipment counts copied from the sizing, rates from past projects, allowances for everything else. As the design changes, the counts in the estimate fall behind the counts in the design — and the budget ends up describing a different building from the one on the drawings.
A bill of quantities that comes from the model
- Quantities from the design. UPS modules, generators, chillers, panels, cables and the rest are counted from the configured design, not re-typed.
- Equipment from leading vendors. Specify and cost equipment from Schneider Electric, Vertiv, Delta, ABB, Eaton, Siemens, Cummins and Caterpillar.
- Schedules included. Panel and cable schedules feed the electrical quantities. How the schedules are built.
- Priced, and kept current. Benchmark rates pre-fill every line and can be adjusted to your market; the priced BoQ updates when the design does.
What a concept-stage data center BoQ should cover
- Electrical — transformers, switchgear, UPS and distribution, with the cabling between them.
- Standby power — generators and their fuel storage.
- Cooling — chillers, pumps, the hydronic loop and its vessels, and the cooling units in the halls.
- Structure for the plant — slabs and steel platforms for generators, chillers and power rooms.
- Buildings and site — the data halls, offices and support spaces the layout defines.
If a line is missing from the design, it is missing from the budget — which is why the BoQ should come from the same model as the sizing and the site layout.
From BoQ to a complete proposal
The bill of quantities sits inside a full proposal — scope, technical design, standards and compliance, schedule, organisation and delivery plan, and cost — exported to PDF, Word and Excel, ready for the client.